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1 //===--- CGExprScalar.cpp - Emit LLVM Code for Scalar Exprs ---------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This contains code to emit Expr nodes with scalar LLVM types as LLVM code.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Frontend/CodeGenOptions.h"
15 #include "CodeGenFunction.h"
16 #include "CGCXXABI.h"
17 #include "CGObjCRuntime.h"
18 #include "CodeGenModule.h"
19 #include "CGDebugInfo.h"
20 #include "clang/AST/ASTContext.h"
21 #include "clang/AST/DeclObjC.h"
22 #include "clang/AST/RecordLayout.h"
23 #include "clang/AST/StmtVisitor.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "llvm/Constants.h"
26 #include "llvm/Function.h"
27 #include "llvm/GlobalVariable.h"
28 #include "llvm/Intrinsics.h"
29 #include "llvm/Module.h"
30 #include "llvm/Support/CFG.h"
31 #include "llvm/Target/TargetData.h"
32 #include <cstdarg>
33 
34 using namespace clang;
35 using namespace CodeGen;
36 using llvm::Value;
37 
38 //===----------------------------------------------------------------------===//
39 //                         Scalar Expression Emitter
40 //===----------------------------------------------------------------------===//
41 
42 namespace {
43 struct BinOpInfo {
44   Value *LHS;
45   Value *RHS;
46   QualType Ty;  // Computation Type.
47   BinaryOperator::Opcode Opcode; // Opcode of BinOp to perform
48   const Expr *E;      // Entire expr, for error unsupported.  May not be binop.
49 };
50 
MustVisitNullValue(const Expr * E)51 static bool MustVisitNullValue(const Expr *E) {
52   // If a null pointer expression's type is the C++0x nullptr_t, then
53   // it's not necessarily a simple constant and it must be evaluated
54   // for its potential side effects.
55   return E->getType()->isNullPtrType();
56 }
57 
58 class ScalarExprEmitter
59   : public StmtVisitor<ScalarExprEmitter, Value*> {
60   CodeGenFunction &CGF;
61   CGBuilderTy &Builder;
62   bool IgnoreResultAssign;
63   llvm::LLVMContext &VMContext;
64 public:
65 
ScalarExprEmitter(CodeGenFunction & cgf,bool ira=false)66   ScalarExprEmitter(CodeGenFunction &cgf, bool ira=false)
67     : CGF(cgf), Builder(CGF.Builder), IgnoreResultAssign(ira),
68       VMContext(cgf.getLLVMContext()) {
69   }
70 
71   //===--------------------------------------------------------------------===//
72   //                               Utilities
73   //===--------------------------------------------------------------------===//
74 
TestAndClearIgnoreResultAssign()75   bool TestAndClearIgnoreResultAssign() {
76     bool I = IgnoreResultAssign;
77     IgnoreResultAssign = false;
78     return I;
79   }
80 
ConvertType(QualType T)81   llvm::Type *ConvertType(QualType T) { return CGF.ConvertType(T); }
EmitLValue(const Expr * E)82   LValue EmitLValue(const Expr *E) { return CGF.EmitLValue(E); }
EmitCheckedLValue(const Expr * E,CodeGenFunction::TypeCheckKind TCK)83   LValue EmitCheckedLValue(const Expr *E, CodeGenFunction::TypeCheckKind TCK) {
84     return CGF.EmitCheckedLValue(E, TCK);
85   }
86 
EmitLoadOfLValue(LValue LV)87   Value *EmitLoadOfLValue(LValue LV) {
88     return CGF.EmitLoadOfLValue(LV).getScalarVal();
89   }
90 
91   /// EmitLoadOfLValue - Given an expression with complex type that represents a
92   /// value l-value, this method emits the address of the l-value, then loads
93   /// and returns the result.
EmitLoadOfLValue(const Expr * E)94   Value *EmitLoadOfLValue(const Expr *E) {
95     return EmitLoadOfLValue(EmitCheckedLValue(E, CodeGenFunction::TCK_Load));
96   }
97 
98   /// EmitConversionToBool - Convert the specified expression value to a
99   /// boolean (i1) truth value.  This is equivalent to "Val != 0".
100   Value *EmitConversionToBool(Value *Src, QualType DstTy);
101 
102   /// EmitScalarConversion - Emit a conversion from the specified type to the
103   /// specified destination type, both of which are LLVM scalar types.
104   Value *EmitScalarConversion(Value *Src, QualType SrcTy, QualType DstTy);
105 
106   /// EmitComplexToScalarConversion - Emit a conversion from the specified
107   /// complex type to the specified destination type, where the destination type
108   /// is an LLVM scalar type.
109   Value *EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,
110                                        QualType SrcTy, QualType DstTy);
111 
112   /// EmitNullValue - Emit a value that corresponds to null for the given type.
113   Value *EmitNullValue(QualType Ty);
114 
115   /// EmitFloatToBoolConversion - Perform an FP to boolean conversion.
EmitFloatToBoolConversion(Value * V)116   Value *EmitFloatToBoolConversion(Value *V) {
117     // Compare against 0.0 for fp scalars.
118     llvm::Value *Zero = llvm::Constant::getNullValue(V->getType());
119     return Builder.CreateFCmpUNE(V, Zero, "tobool");
120   }
121 
122   /// EmitPointerToBoolConversion - Perform a pointer to boolean conversion.
EmitPointerToBoolConversion(Value * V)123   Value *EmitPointerToBoolConversion(Value *V) {
124     Value *Zero = llvm::ConstantPointerNull::get(
125                                       cast<llvm::PointerType>(V->getType()));
126     return Builder.CreateICmpNE(V, Zero, "tobool");
127   }
128 
EmitIntToBoolConversion(Value * V)129   Value *EmitIntToBoolConversion(Value *V) {
130     // Because of the type rules of C, we often end up computing a
131     // logical value, then zero extending it to int, then wanting it
132     // as a logical value again.  Optimize this common case.
133     if (llvm::ZExtInst *ZI = dyn_cast<llvm::ZExtInst>(V)) {
134       if (ZI->getOperand(0)->getType() == Builder.getInt1Ty()) {
135         Value *Result = ZI->getOperand(0);
136         // If there aren't any more uses, zap the instruction to save space.
137         // Note that there can be more uses, for example if this
138         // is the result of an assignment.
139         if (ZI->use_empty())
140           ZI->eraseFromParent();
141         return Result;
142       }
143     }
144 
145     return Builder.CreateIsNotNull(V, "tobool");
146   }
147 
148   //===--------------------------------------------------------------------===//
149   //                            Visitor Methods
150   //===--------------------------------------------------------------------===//
151 
Visit(Expr * E)152   Value *Visit(Expr *E) {
153     return StmtVisitor<ScalarExprEmitter, Value*>::Visit(E);
154   }
155 
VisitStmt(Stmt * S)156   Value *VisitStmt(Stmt *S) {
157     S->dump(CGF.getContext().getSourceManager());
158     llvm_unreachable("Stmt can't have complex result type!");
159   }
160   Value *VisitExpr(Expr *S);
161 
VisitParenExpr(ParenExpr * PE)162   Value *VisitParenExpr(ParenExpr *PE) {
163     return Visit(PE->getSubExpr());
164   }
VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr * E)165   Value *VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) {
166     return Visit(E->getReplacement());
167   }
VisitGenericSelectionExpr(GenericSelectionExpr * GE)168   Value *VisitGenericSelectionExpr(GenericSelectionExpr *GE) {
169     return Visit(GE->getResultExpr());
170   }
171 
172   // Leaves.
VisitIntegerLiteral(const IntegerLiteral * E)173   Value *VisitIntegerLiteral(const IntegerLiteral *E) {
174     return Builder.getInt(E->getValue());
175   }
VisitFloatingLiteral(const FloatingLiteral * E)176   Value *VisitFloatingLiteral(const FloatingLiteral *E) {
177     return llvm::ConstantFP::get(VMContext, E->getValue());
178   }
VisitCharacterLiteral(const CharacterLiteral * E)179   Value *VisitCharacterLiteral(const CharacterLiteral *E) {
180     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
181   }
VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr * E)182   Value *VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
183     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
184   }
VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr * E)185   Value *VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
186     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
187   }
VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr * E)188   Value *VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
189     return EmitNullValue(E->getType());
190   }
VisitGNUNullExpr(const GNUNullExpr * E)191   Value *VisitGNUNullExpr(const GNUNullExpr *E) {
192     return EmitNullValue(E->getType());
193   }
194   Value *VisitOffsetOfExpr(OffsetOfExpr *E);
195   Value *VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
VisitAddrLabelExpr(const AddrLabelExpr * E)196   Value *VisitAddrLabelExpr(const AddrLabelExpr *E) {
197     llvm::Value *V = CGF.GetAddrOfLabel(E->getLabel());
198     return Builder.CreateBitCast(V, ConvertType(E->getType()));
199   }
200 
VisitSizeOfPackExpr(SizeOfPackExpr * E)201   Value *VisitSizeOfPackExpr(SizeOfPackExpr *E) {
202     return llvm::ConstantInt::get(ConvertType(E->getType()),E->getPackLength());
203   }
204 
VisitPseudoObjectExpr(PseudoObjectExpr * E)205   Value *VisitPseudoObjectExpr(PseudoObjectExpr *E) {
206     return CGF.EmitPseudoObjectRValue(E).getScalarVal();
207   }
208 
VisitOpaqueValueExpr(OpaqueValueExpr * E)209   Value *VisitOpaqueValueExpr(OpaqueValueExpr *E) {
210     if (E->isGLValue())
211       return EmitLoadOfLValue(CGF.getOpaqueLValueMapping(E));
212 
213     // Otherwise, assume the mapping is the scalar directly.
214     return CGF.getOpaqueRValueMapping(E).getScalarVal();
215   }
216 
217   // l-values.
VisitDeclRefExpr(DeclRefExpr * E)218   Value *VisitDeclRefExpr(DeclRefExpr *E) {
219     if (CodeGenFunction::ConstantEmission result = CGF.tryEmitAsConstant(E)) {
220       if (result.isReference())
221         return EmitLoadOfLValue(result.getReferenceLValue(CGF, E));
222       return result.getValue();
223     }
224     return EmitLoadOfLValue(E);
225   }
226 
VisitObjCSelectorExpr(ObjCSelectorExpr * E)227   Value *VisitObjCSelectorExpr(ObjCSelectorExpr *E) {
228     return CGF.EmitObjCSelectorExpr(E);
229   }
VisitObjCProtocolExpr(ObjCProtocolExpr * E)230   Value *VisitObjCProtocolExpr(ObjCProtocolExpr *E) {
231     return CGF.EmitObjCProtocolExpr(E);
232   }
VisitObjCIvarRefExpr(ObjCIvarRefExpr * E)233   Value *VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
234     return EmitLoadOfLValue(E);
235   }
VisitObjCMessageExpr(ObjCMessageExpr * E)236   Value *VisitObjCMessageExpr(ObjCMessageExpr *E) {
237     if (E->getMethodDecl() &&
238         E->getMethodDecl()->getResultType()->isReferenceType())
239       return EmitLoadOfLValue(E);
240     return CGF.EmitObjCMessageExpr(E).getScalarVal();
241   }
242 
VisitObjCIsaExpr(ObjCIsaExpr * E)243   Value *VisitObjCIsaExpr(ObjCIsaExpr *E) {
244     LValue LV = CGF.EmitObjCIsaExpr(E);
245     Value *V = CGF.EmitLoadOfLValue(LV).getScalarVal();
246     return V;
247   }
248 
249   Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
250   Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
251   Value *VisitMemberExpr(MemberExpr *E);
VisitExtVectorElementExpr(Expr * E)252   Value *VisitExtVectorElementExpr(Expr *E) { return EmitLoadOfLValue(E); }
VisitCompoundLiteralExpr(CompoundLiteralExpr * E)253   Value *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
254     return EmitLoadOfLValue(E);
255   }
256 
257   Value *VisitInitListExpr(InitListExpr *E);
258 
VisitImplicitValueInitExpr(const ImplicitValueInitExpr * E)259   Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
260     return CGF.CGM.EmitNullConstant(E->getType());
261   }
VisitExplicitCastExpr(ExplicitCastExpr * E)262   Value *VisitExplicitCastExpr(ExplicitCastExpr *E) {
263     if (E->getType()->isVariablyModifiedType())
264       CGF.EmitVariablyModifiedType(E->getType());
265     return VisitCastExpr(E);
266   }
267   Value *VisitCastExpr(CastExpr *E);
268 
VisitCallExpr(const CallExpr * E)269   Value *VisitCallExpr(const CallExpr *E) {
270     if (E->getCallReturnType()->isReferenceType())
271       return EmitLoadOfLValue(E);
272 
273     return CGF.EmitCallExpr(E).getScalarVal();
274   }
275 
276   Value *VisitStmtExpr(const StmtExpr *E);
277 
278   // Unary Operators.
VisitUnaryPostDec(const UnaryOperator * E)279   Value *VisitUnaryPostDec(const UnaryOperator *E) {
280     LValue LV = EmitLValue(E->getSubExpr());
281     return EmitScalarPrePostIncDec(E, LV, false, false);
282   }
VisitUnaryPostInc(const UnaryOperator * E)283   Value *VisitUnaryPostInc(const UnaryOperator *E) {
284     LValue LV = EmitLValue(E->getSubExpr());
285     return EmitScalarPrePostIncDec(E, LV, true, false);
286   }
VisitUnaryPreDec(const UnaryOperator * E)287   Value *VisitUnaryPreDec(const UnaryOperator *E) {
288     LValue LV = EmitLValue(E->getSubExpr());
289     return EmitScalarPrePostIncDec(E, LV, false, true);
290   }
VisitUnaryPreInc(const UnaryOperator * E)291   Value *VisitUnaryPreInc(const UnaryOperator *E) {
292     LValue LV = EmitLValue(E->getSubExpr());
293     return EmitScalarPrePostIncDec(E, LV, true, true);
294   }
295 
296   llvm::Value *EmitAddConsiderOverflowBehavior(const UnaryOperator *E,
297                                                llvm::Value *InVal,
298                                                llvm::Value *NextVal,
299                                                bool IsInc);
300 
301   llvm::Value *EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
302                                        bool isInc, bool isPre);
303 
304 
VisitUnaryAddrOf(const UnaryOperator * E)305   Value *VisitUnaryAddrOf(const UnaryOperator *E) {
306     if (isa<MemberPointerType>(E->getType())) // never sugared
307       return CGF.CGM.getMemberPointerConstant(E);
308 
309     return EmitLValue(E->getSubExpr()).getAddress();
310   }
VisitUnaryDeref(const UnaryOperator * E)311   Value *VisitUnaryDeref(const UnaryOperator *E) {
312     if (E->getType()->isVoidType())
313       return Visit(E->getSubExpr()); // the actual value should be unused
314     return EmitLoadOfLValue(E);
315   }
VisitUnaryPlus(const UnaryOperator * E)316   Value *VisitUnaryPlus(const UnaryOperator *E) {
317     // This differs from gcc, though, most likely due to a bug in gcc.
318     TestAndClearIgnoreResultAssign();
319     return Visit(E->getSubExpr());
320   }
321   Value *VisitUnaryMinus    (const UnaryOperator *E);
322   Value *VisitUnaryNot      (const UnaryOperator *E);
323   Value *VisitUnaryLNot     (const UnaryOperator *E);
324   Value *VisitUnaryReal     (const UnaryOperator *E);
325   Value *VisitUnaryImag     (const UnaryOperator *E);
VisitUnaryExtension(const UnaryOperator * E)326   Value *VisitUnaryExtension(const UnaryOperator *E) {
327     return Visit(E->getSubExpr());
328   }
329 
330   // C++
VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr * E)331   Value *VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E) {
332     return EmitLoadOfLValue(E);
333   }
334 
VisitCXXDefaultArgExpr(CXXDefaultArgExpr * DAE)335   Value *VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) {
336     return Visit(DAE->getExpr());
337   }
VisitCXXThisExpr(CXXThisExpr * TE)338   Value *VisitCXXThisExpr(CXXThisExpr *TE) {
339     return CGF.LoadCXXThis();
340   }
341 
VisitExprWithCleanups(ExprWithCleanups * E)342   Value *VisitExprWithCleanups(ExprWithCleanups *E) {
343     CGF.enterFullExpression(E);
344     CodeGenFunction::RunCleanupsScope Scope(CGF);
345     return Visit(E->getSubExpr());
346   }
VisitCXXNewExpr(const CXXNewExpr * E)347   Value *VisitCXXNewExpr(const CXXNewExpr *E) {
348     return CGF.EmitCXXNewExpr(E);
349   }
VisitCXXDeleteExpr(const CXXDeleteExpr * E)350   Value *VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
351     CGF.EmitCXXDeleteExpr(E);
352     return 0;
353   }
VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr * E)354   Value *VisitUnaryTypeTraitExpr(const UnaryTypeTraitExpr *E) {
355     return Builder.getInt1(E->getValue());
356   }
357 
VisitBinaryTypeTraitExpr(const BinaryTypeTraitExpr * E)358   Value *VisitBinaryTypeTraitExpr(const BinaryTypeTraitExpr *E) {
359     return llvm::ConstantInt::get(ConvertType(E->getType()), E->getValue());
360   }
361 
VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr * E)362   Value *VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
363     return llvm::ConstantInt::get(Builder.getInt32Ty(), E->getValue());
364   }
365 
VisitExpressionTraitExpr(const ExpressionTraitExpr * E)366   Value *VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
367     return llvm::ConstantInt::get(Builder.getInt1Ty(), E->getValue());
368   }
369 
VisitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr * E)370   Value *VisitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr *E) {
371     // C++ [expr.pseudo]p1:
372     //   The result shall only be used as the operand for the function call
373     //   operator (), and the result of such a call has type void. The only
374     //   effect is the evaluation of the postfix-expression before the dot or
375     //   arrow.
376     CGF.EmitScalarExpr(E->getBase());
377     return 0;
378   }
379 
VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr * E)380   Value *VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
381     return EmitNullValue(E->getType());
382   }
383 
VisitCXXThrowExpr(const CXXThrowExpr * E)384   Value *VisitCXXThrowExpr(const CXXThrowExpr *E) {
385     CGF.EmitCXXThrowExpr(E);
386     return 0;
387   }
388 
VisitCXXNoexceptExpr(const CXXNoexceptExpr * E)389   Value *VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
390     return Builder.getInt1(E->getValue());
391   }
392 
393   // Binary Operators.
EmitMul(const BinOpInfo & Ops)394   Value *EmitMul(const BinOpInfo &Ops) {
395     if (Ops.Ty->isSignedIntegerOrEnumerationType()) {
396       switch (CGF.getContext().getLangOpts().getSignedOverflowBehavior()) {
397       case LangOptions::SOB_Defined:
398         return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
399       case LangOptions::SOB_Undefined:
400         if (!CGF.CatchUndefined)
401           return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul");
402         // Fall through.
403       case LangOptions::SOB_Trapping:
404         return EmitOverflowCheckedBinOp(Ops);
405       }
406     }
407 
408     if (Ops.LHS->getType()->isFPOrFPVectorTy())
409       return Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul");
410     return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
411   }
isTrapvOverflowBehavior()412   bool isTrapvOverflowBehavior() {
413     return CGF.getContext().getLangOpts().getSignedOverflowBehavior()
414                == LangOptions::SOB_Trapping || CGF.CatchUndefined;
415   }
416   /// Create a binary op that checks for overflow.
417   /// Currently only supports +, - and *.
418   Value *EmitOverflowCheckedBinOp(const BinOpInfo &Ops);
419 
420   // Check for undefined division and modulus behaviors.
421   void EmitUndefinedBehaviorIntegerDivAndRemCheck(const BinOpInfo &Ops,
422                                                   llvm::Value *Zero,bool isDiv);
423   Value *EmitDiv(const BinOpInfo &Ops);
424   Value *EmitRem(const BinOpInfo &Ops);
425   Value *EmitAdd(const BinOpInfo &Ops);
426   Value *EmitSub(const BinOpInfo &Ops);
427   Value *EmitShl(const BinOpInfo &Ops);
428   Value *EmitShr(const BinOpInfo &Ops);
EmitAnd(const BinOpInfo & Ops)429   Value *EmitAnd(const BinOpInfo &Ops) {
430     return Builder.CreateAnd(Ops.LHS, Ops.RHS, "and");
431   }
EmitXor(const BinOpInfo & Ops)432   Value *EmitXor(const BinOpInfo &Ops) {
433     return Builder.CreateXor(Ops.LHS, Ops.RHS, "xor");
434   }
EmitOr(const BinOpInfo & Ops)435   Value *EmitOr (const BinOpInfo &Ops) {
436     return Builder.CreateOr(Ops.LHS, Ops.RHS, "or");
437   }
438 
439   BinOpInfo EmitBinOps(const BinaryOperator *E);
440   LValue EmitCompoundAssignLValue(const CompoundAssignOperator *E,
441                             Value *(ScalarExprEmitter::*F)(const BinOpInfo &),
442                                   Value *&Result);
443 
444   Value *EmitCompoundAssign(const CompoundAssignOperator *E,
445                             Value *(ScalarExprEmitter::*F)(const BinOpInfo &));
446 
447   // Binary operators and binary compound assignment operators.
448 #define HANDLEBINOP(OP) \
449   Value *VisitBin ## OP(const BinaryOperator *E) {                         \
450     return Emit ## OP(EmitBinOps(E));                                      \
451   }                                                                        \
452   Value *VisitBin ## OP ## Assign(const CompoundAssignOperator *E) {       \
453     return EmitCompoundAssign(E, &ScalarExprEmitter::Emit ## OP);          \
454   }
455   HANDLEBINOP(Mul)
456   HANDLEBINOP(Div)
457   HANDLEBINOP(Rem)
458   HANDLEBINOP(Add)
459   HANDLEBINOP(Sub)
460   HANDLEBINOP(Shl)
461   HANDLEBINOP(Shr)
462   HANDLEBINOP(And)
463   HANDLEBINOP(Xor)
464   HANDLEBINOP(Or)
465 #undef HANDLEBINOP
466 
467   // Comparisons.
468   Value *EmitCompare(const BinaryOperator *E, unsigned UICmpOpc,
469                      unsigned SICmpOpc, unsigned FCmpOpc);
470 #define VISITCOMP(CODE, UI, SI, FP) \
471     Value *VisitBin##CODE(const BinaryOperator *E) { \
472       return EmitCompare(E, llvm::ICmpInst::UI, llvm::ICmpInst::SI, \
473                          llvm::FCmpInst::FP); }
474   VISITCOMP(LT, ICMP_ULT, ICMP_SLT, FCMP_OLT)
475   VISITCOMP(GT, ICMP_UGT, ICMP_SGT, FCMP_OGT)
476   VISITCOMP(LE, ICMP_ULE, ICMP_SLE, FCMP_OLE)
477   VISITCOMP(GE, ICMP_UGE, ICMP_SGE, FCMP_OGE)
478   VISITCOMP(EQ, ICMP_EQ , ICMP_EQ , FCMP_OEQ)
479   VISITCOMP(NE, ICMP_NE , ICMP_NE , FCMP_UNE)
480 #undef VISITCOMP
481 
482   Value *VisitBinAssign     (const BinaryOperator *E);
483 
484   Value *VisitBinLAnd       (const BinaryOperator *E);
485   Value *VisitBinLOr        (const BinaryOperator *E);
486   Value *VisitBinComma      (const BinaryOperator *E);
487 
VisitBinPtrMemD(const Expr * E)488   Value *VisitBinPtrMemD(const Expr *E) { return EmitLoadOfLValue(E); }
VisitBinPtrMemI(const Expr * E)489   Value *VisitBinPtrMemI(const Expr *E) { return EmitLoadOfLValue(E); }
490 
491   // Other Operators.
492   Value *VisitBlockExpr(const BlockExpr *BE);
493   Value *VisitAbstractConditionalOperator(const AbstractConditionalOperator *);
494   Value *VisitChooseExpr(ChooseExpr *CE);
495   Value *VisitVAArgExpr(VAArgExpr *VE);
VisitObjCStringLiteral(const ObjCStringLiteral * E)496   Value *VisitObjCStringLiteral(const ObjCStringLiteral *E) {
497     return CGF.EmitObjCStringLiteral(E);
498   }
VisitObjCBoxedExpr(ObjCBoxedExpr * E)499   Value *VisitObjCBoxedExpr(ObjCBoxedExpr *E) {
500     return CGF.EmitObjCBoxedExpr(E);
501   }
VisitObjCArrayLiteral(ObjCArrayLiteral * E)502   Value *VisitObjCArrayLiteral(ObjCArrayLiteral *E) {
503     return CGF.EmitObjCArrayLiteral(E);
504   }
VisitObjCDictionaryLiteral(ObjCDictionaryLiteral * E)505   Value *VisitObjCDictionaryLiteral(ObjCDictionaryLiteral *E) {
506     return CGF.EmitObjCDictionaryLiteral(E);
507   }
508   Value *VisitAsTypeExpr(AsTypeExpr *CE);
509   Value *VisitAtomicExpr(AtomicExpr *AE);
510 };
511 }  // end anonymous namespace.
512 
513 //===----------------------------------------------------------------------===//
514 //                                Utilities
515 //===----------------------------------------------------------------------===//
516 
517 /// EmitConversionToBool - Convert the specified expression value to a
518 /// boolean (i1) truth value.  This is equivalent to "Val != 0".
EmitConversionToBool(Value * Src,QualType SrcType)519 Value *ScalarExprEmitter::EmitConversionToBool(Value *Src, QualType SrcType) {
520   assert(SrcType.isCanonical() && "EmitScalarConversion strips typedefs");
521 
522   if (SrcType->isRealFloatingType())
523     return EmitFloatToBoolConversion(Src);
524 
525   if (const MemberPointerType *MPT = dyn_cast<MemberPointerType>(SrcType))
526     return CGF.CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, Src, MPT);
527 
528   assert((SrcType->isIntegerType() || isa<llvm::PointerType>(Src->getType())) &&
529          "Unknown scalar type to convert");
530 
531   if (isa<llvm::IntegerType>(Src->getType()))
532     return EmitIntToBoolConversion(Src);
533 
534   assert(isa<llvm::PointerType>(Src->getType()));
535   return EmitPointerToBoolConversion(Src);
536 }
537 
538 /// EmitScalarConversion - Emit a conversion from the specified type to the
539 /// specified destination type, both of which are LLVM scalar types.
EmitScalarConversion(Value * Src,QualType SrcType,QualType DstType)540 Value *ScalarExprEmitter::EmitScalarConversion(Value *Src, QualType SrcType,
541                                                QualType DstType) {
542   SrcType = CGF.getContext().getCanonicalType(SrcType);
543   DstType = CGF.getContext().getCanonicalType(DstType);
544   if (SrcType == DstType) return Src;
545 
546   if (DstType->isVoidType()) return 0;
547 
548   llvm::Type *SrcTy = Src->getType();
549 
550   // Floating casts might be a bit special: if we're doing casts to / from half
551   // FP, we should go via special intrinsics.
552   if (SrcType->isHalfType()) {
553     Src = Builder.CreateCall(CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16), Src);
554     SrcType = CGF.getContext().FloatTy;
555     SrcTy = CGF.FloatTy;
556   }
557 
558   // Handle conversions to bool first, they are special: comparisons against 0.
559   if (DstType->isBooleanType())
560     return EmitConversionToBool(Src, SrcType);
561 
562   llvm::Type *DstTy = ConvertType(DstType);
563 
564   // Ignore conversions like int -> uint.
565   if (SrcTy == DstTy)
566     return Src;
567 
568   // Handle pointer conversions next: pointers can only be converted to/from
569   // other pointers and integers. Check for pointer types in terms of LLVM, as
570   // some native types (like Obj-C id) may map to a pointer type.
571   if (isa<llvm::PointerType>(DstTy)) {
572     // The source value may be an integer, or a pointer.
573     if (isa<llvm::PointerType>(SrcTy))
574       return Builder.CreateBitCast(Src, DstTy, "conv");
575 
576     assert(SrcType->isIntegerType() && "Not ptr->ptr or int->ptr conversion?");
577     // First, convert to the correct width so that we control the kind of
578     // extension.
579     llvm::Type *MiddleTy = CGF.IntPtrTy;
580     bool InputSigned = SrcType->isSignedIntegerOrEnumerationType();
581     llvm::Value* IntResult =
582         Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
583     // Then, cast to pointer.
584     return Builder.CreateIntToPtr(IntResult, DstTy, "conv");
585   }
586 
587   if (isa<llvm::PointerType>(SrcTy)) {
588     // Must be an ptr to int cast.
589     assert(isa<llvm::IntegerType>(DstTy) && "not ptr->int?");
590     return Builder.CreatePtrToInt(Src, DstTy, "conv");
591   }
592 
593   // A scalar can be splatted to an extended vector of the same element type
594   if (DstType->isExtVectorType() && !SrcType->isVectorType()) {
595     // Cast the scalar to element type
596     QualType EltTy = DstType->getAs<ExtVectorType>()->getElementType();
597     llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy);
598 
599     // Insert the element in element zero of an undef vector
600     llvm::Value *UnV = llvm::UndefValue::get(DstTy);
601     llvm::Value *Idx = Builder.getInt32(0);
602     UnV = Builder.CreateInsertElement(UnV, Elt, Idx);
603 
604     // Splat the element across to all elements
605     unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements();
606     llvm::Constant *Mask = llvm::ConstantVector::getSplat(NumElements,
607                                                           Builder.getInt32(0));
608     llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat");
609     return Yay;
610   }
611 
612   // Allow bitcast from vector to integer/fp of the same size.
613   if (isa<llvm::VectorType>(SrcTy) ||
614       isa<llvm::VectorType>(DstTy))
615     return Builder.CreateBitCast(Src, DstTy, "conv");
616 
617   // Finally, we have the arithmetic types: real int/float.
618   Value *Res = NULL;
619   llvm::Type *ResTy = DstTy;
620 
621   // Cast to half via float
622   if (DstType->isHalfType())
623     DstTy = CGF.FloatTy;
624 
625   if (isa<llvm::IntegerType>(SrcTy)) {
626     bool InputSigned = SrcType->isSignedIntegerOrEnumerationType();
627     if (isa<llvm::IntegerType>(DstTy))
628       Res = Builder.CreateIntCast(Src, DstTy, InputSigned, "conv");
629     else if (InputSigned)
630       Res = Builder.CreateSIToFP(Src, DstTy, "conv");
631     else
632       Res = Builder.CreateUIToFP(Src, DstTy, "conv");
633   } else if (isa<llvm::IntegerType>(DstTy)) {
634     assert(SrcTy->isFloatingPointTy() && "Unknown real conversion");
635     if (DstType->isSignedIntegerOrEnumerationType())
636       Res = Builder.CreateFPToSI(Src, DstTy, "conv");
637     else
638       Res = Builder.CreateFPToUI(Src, DstTy, "conv");
639   } else {
640     assert(SrcTy->isFloatingPointTy() && DstTy->isFloatingPointTy() &&
641            "Unknown real conversion");
642     if (DstTy->getTypeID() < SrcTy->getTypeID())
643       Res = Builder.CreateFPTrunc(Src, DstTy, "conv");
644     else
645       Res = Builder.CreateFPExt(Src, DstTy, "conv");
646   }
647 
648   if (DstTy != ResTy) {
649     assert(ResTy->isIntegerTy(16) && "Only half FP requires extra conversion");
650     Res = Builder.CreateCall(CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16), Res);
651   }
652 
653   return Res;
654 }
655 
656 /// EmitComplexToScalarConversion - Emit a conversion from the specified complex
657 /// type to the specified destination type, where the destination type is an
658 /// LLVM scalar type.
659 Value *ScalarExprEmitter::
EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,QualType SrcTy,QualType DstTy)660 EmitComplexToScalarConversion(CodeGenFunction::ComplexPairTy Src,
661                               QualType SrcTy, QualType DstTy) {
662   // Get the source element type.
663   SrcTy = SrcTy->getAs<ComplexType>()->getElementType();
664 
665   // Handle conversions to bool first, they are special: comparisons against 0.
666   if (DstTy->isBooleanType()) {
667     //  Complex != 0  -> (Real != 0) | (Imag != 0)
668     Src.first  = EmitScalarConversion(Src.first, SrcTy, DstTy);
669     Src.second = EmitScalarConversion(Src.second, SrcTy, DstTy);
670     return Builder.CreateOr(Src.first, Src.second, "tobool");
671   }
672 
673   // C99 6.3.1.7p2: "When a value of complex type is converted to a real type,
674   // the imaginary part of the complex value is discarded and the value of the
675   // real part is converted according to the conversion rules for the
676   // corresponding real type.
677   return EmitScalarConversion(Src.first, SrcTy, DstTy);
678 }
679 
EmitNullValue(QualType Ty)680 Value *ScalarExprEmitter::EmitNullValue(QualType Ty) {
681   if (const MemberPointerType *MPT = Ty->getAs<MemberPointerType>())
682     return CGF.CGM.getCXXABI().EmitNullMemberPointer(MPT);
683 
684   return llvm::Constant::getNullValue(ConvertType(Ty));
685 }
686 
687 //===----------------------------------------------------------------------===//
688 //                            Visitor Methods
689 //===----------------------------------------------------------------------===//
690 
VisitExpr(Expr * E)691 Value *ScalarExprEmitter::VisitExpr(Expr *E) {
692   CGF.ErrorUnsupported(E, "scalar expression");
693   if (E->getType()->isVoidType())
694     return 0;
695   return llvm::UndefValue::get(CGF.ConvertType(E->getType()));
696 }
697 
VisitShuffleVectorExpr(ShuffleVectorExpr * E)698 Value *ScalarExprEmitter::VisitShuffleVectorExpr(ShuffleVectorExpr *E) {
699   // Vector Mask Case
700   if (E->getNumSubExprs() == 2 ||
701       (E->getNumSubExprs() == 3 && E->getExpr(2)->getType()->isVectorType())) {
702     Value *LHS = CGF.EmitScalarExpr(E->getExpr(0));
703     Value *RHS = CGF.EmitScalarExpr(E->getExpr(1));
704     Value *Mask;
705 
706     llvm::VectorType *LTy = cast<llvm::VectorType>(LHS->getType());
707     unsigned LHSElts = LTy->getNumElements();
708 
709     if (E->getNumSubExprs() == 3) {
710       Mask = CGF.EmitScalarExpr(E->getExpr(2));
711 
712       // Shuffle LHS & RHS into one input vector.
713       SmallVector<llvm::Constant*, 32> concat;
714       for (unsigned i = 0; i != LHSElts; ++i) {
715         concat.push_back(Builder.getInt32(2*i));
716         concat.push_back(Builder.getInt32(2*i+1));
717       }
718 
719       Value* CV = llvm::ConstantVector::get(concat);
720       LHS = Builder.CreateShuffleVector(LHS, RHS, CV, "concat");
721       LHSElts *= 2;
722     } else {
723       Mask = RHS;
724     }
725 
726     llvm::VectorType *MTy = cast<llvm::VectorType>(Mask->getType());
727     llvm::Constant* EltMask;
728 
729     // Treat vec3 like vec4.
730     if ((LHSElts == 6) && (E->getNumSubExprs() == 3))
731       EltMask = llvm::ConstantInt::get(MTy->getElementType(),
732                                        (1 << llvm::Log2_32(LHSElts+2))-1);
733     else if ((LHSElts == 3) && (E->getNumSubExprs() == 2))
734       EltMask = llvm::ConstantInt::get(MTy->getElementType(),
735                                        (1 << llvm::Log2_32(LHSElts+1))-1);
736     else
737       EltMask = llvm::ConstantInt::get(MTy->getElementType(),
738                                        (1 << llvm::Log2_32(LHSElts))-1);
739 
740     // Mask off the high bits of each shuffle index.
741     Value *MaskBits = llvm::ConstantVector::getSplat(MTy->getNumElements(),
742                                                      EltMask);
743     Mask = Builder.CreateAnd(Mask, MaskBits, "mask");
744 
745     // newv = undef
746     // mask = mask & maskbits
747     // for each elt
748     //   n = extract mask i
749     //   x = extract val n
750     //   newv = insert newv, x, i
751     llvm::VectorType *RTy = llvm::VectorType::get(LTy->getElementType(),
752                                                         MTy->getNumElements());
753     Value* NewV = llvm::UndefValue::get(RTy);
754     for (unsigned i = 0, e = MTy->getNumElements(); i != e; ++i) {
755       Value *IIndx = Builder.getInt32(i);
756       Value *Indx = Builder.CreateExtractElement(Mask, IIndx, "shuf_idx");
757       Indx = Builder.CreateZExt(Indx, CGF.Int32Ty, "idx_zext");
758 
759       // Handle vec3 special since the index will be off by one for the RHS.
760       if ((LHSElts == 6) && (E->getNumSubExprs() == 3)) {
761         Value *cmpIndx, *newIndx;
762         cmpIndx = Builder.CreateICmpUGT(Indx, Builder.getInt32(3),
763                                         "cmp_shuf_idx");
764         newIndx = Builder.CreateSub(Indx, Builder.getInt32(1), "shuf_idx_adj");
765         Indx = Builder.CreateSelect(cmpIndx, newIndx, Indx, "sel_shuf_idx");
766       }
767       Value *VExt = Builder.CreateExtractElement(LHS, Indx, "shuf_elt");
768       NewV = Builder.CreateInsertElement(NewV, VExt, IIndx, "shuf_ins");
769     }
770     return NewV;
771   }
772 
773   Value* V1 = CGF.EmitScalarExpr(E->getExpr(0));
774   Value* V2 = CGF.EmitScalarExpr(E->getExpr(1));
775 
776   // Handle vec3 special since the index will be off by one for the RHS.
777   llvm::VectorType *VTy = cast<llvm::VectorType>(V1->getType());
778   SmallVector<llvm::Constant*, 32> indices;
779   for (unsigned i = 2; i < E->getNumSubExprs(); i++) {
780     unsigned Idx = E->getShuffleMaskIdx(CGF.getContext(), i-2);
781     if (VTy->getNumElements() == 3 && Idx > 3)
782       Idx -= 1;
783     indices.push_back(Builder.getInt32(Idx));
784   }
785 
786   Value *SV = llvm::ConstantVector::get(indices);
787   return Builder.CreateShuffleVector(V1, V2, SV, "shuffle");
788 }
VisitMemberExpr(MemberExpr * E)789 Value *ScalarExprEmitter::VisitMemberExpr(MemberExpr *E) {
790   llvm::APSInt Value;
791   if (E->EvaluateAsInt(Value, CGF.getContext(), Expr::SE_AllowSideEffects)) {
792     if (E->isArrow())
793       CGF.EmitScalarExpr(E->getBase());
794     else
795       EmitLValue(E->getBase());
796     return Builder.getInt(Value);
797   }
798 
799   // Emit debug info for aggregate now, if it was delayed to reduce
800   // debug info size.
801   CGDebugInfo *DI = CGF.getDebugInfo();
802   if (DI &&
803       CGF.CGM.getCodeGenOpts().DebugInfo == CodeGenOptions::LimitedDebugInfo) {
804     QualType PQTy = E->getBase()->IgnoreParenImpCasts()->getType();
805     if (const PointerType * PTy = dyn_cast<PointerType>(PQTy))
806       if (FieldDecl *M = dyn_cast<FieldDecl>(E->getMemberDecl()))
807         DI->getOrCreateRecordType(PTy->getPointeeType(),
808                                   M->getParent()->getLocation());
809   }
810   return EmitLoadOfLValue(E);
811 }
812 
VisitArraySubscriptExpr(ArraySubscriptExpr * E)813 Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
814   TestAndClearIgnoreResultAssign();
815 
816   // Emit subscript expressions in rvalue context's.  For most cases, this just
817   // loads the lvalue formed by the subscript expr.  However, we have to be
818   // careful, because the base of a vector subscript is occasionally an rvalue,
819   // so we can't get it as an lvalue.
820   if (!E->getBase()->getType()->isVectorType())
821     return EmitLoadOfLValue(E);
822 
823   // Handle the vector case.  The base must be a vector, the index must be an
824   // integer value.
825   Value *Base = Visit(E->getBase());
826   Value *Idx  = Visit(E->getIdx());
827   bool IdxSigned = E->getIdx()->getType()->isSignedIntegerOrEnumerationType();
828   Idx = Builder.CreateIntCast(Idx, CGF.Int32Ty, IdxSigned, "vecidxcast");
829   return Builder.CreateExtractElement(Base, Idx, "vecext");
830 }
831 
getMaskElt(llvm::ShuffleVectorInst * SVI,unsigned Idx,unsigned Off,llvm::Type * I32Ty)832 static llvm::Constant *getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx,
833                                   unsigned Off, llvm::Type *I32Ty) {
834   int MV = SVI->getMaskValue(Idx);
835   if (MV == -1)
836     return llvm::UndefValue::get(I32Ty);
837   return llvm::ConstantInt::get(I32Ty, Off+MV);
838 }
839 
VisitInitListExpr(InitListExpr * E)840 Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
841   bool Ignore = TestAndClearIgnoreResultAssign();
842   (void)Ignore;
843   assert (Ignore == false && "init list ignored");
844   unsigned NumInitElements = E->getNumInits();
845 
846   if (E->hadArrayRangeDesignator())
847     CGF.ErrorUnsupported(E, "GNU array range designator extension");
848 
849   llvm::VectorType *VType =
850     dyn_cast<llvm::VectorType>(ConvertType(E->getType()));
851 
852   if (!VType) {
853     if (NumInitElements == 0) {
854       // C++11 value-initialization for the scalar.
855       return EmitNullValue(E->getType());
856     }
857     // We have a scalar in braces. Just use the first element.
858     return Visit(E->getInit(0));
859   }
860 
861   unsigned ResElts = VType->getNumElements();
862 
863   // Loop over initializers collecting the Value for each, and remembering
864   // whether the source was swizzle (ExtVectorElementExpr).  This will allow
865   // us to fold the shuffle for the swizzle into the shuffle for the vector
866   // initializer, since LLVM optimizers generally do not want to touch
867   // shuffles.
868   unsigned CurIdx = 0;
869   bool VIsUndefShuffle = false;
870   llvm::Value *V = llvm::UndefValue::get(VType);
871   for (unsigned i = 0; i != NumInitElements; ++i) {
872     Expr *IE = E->getInit(i);
873     Value *Init = Visit(IE);
874     SmallVector<llvm::Constant*, 16> Args;
875 
876     llvm::VectorType *VVT = dyn_cast<llvm::VectorType>(Init->getType());
877 
878     // Handle scalar elements.  If the scalar initializer is actually one
879     // element of a different vector of the same width, use shuffle instead of
880     // extract+insert.
881     if (!VVT) {
882       if (isa<ExtVectorElementExpr>(IE)) {
883         llvm::ExtractElementInst *EI = cast<llvm::ExtractElementInst>(Init);
884 
885         if (EI->getVectorOperandType()->getNumElements() == ResElts) {
886           llvm::ConstantInt *C = cast<llvm::ConstantInt>(EI->getIndexOperand());
887           Value *LHS = 0, *RHS = 0;
888           if (CurIdx == 0) {
889             // insert into undef -> shuffle (src, undef)
890             Args.push_back(C);
891             Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
892 
893             LHS = EI->getVectorOperand();
894             RHS = V;
895             VIsUndefShuffle = true;
896           } else if (VIsUndefShuffle) {
897             // insert into undefshuffle && size match -> shuffle (v, src)
898             llvm::ShuffleVectorInst *SVV = cast<llvm::ShuffleVectorInst>(V);
899             for (unsigned j = 0; j != CurIdx; ++j)
900               Args.push_back(getMaskElt(SVV, j, 0, CGF.Int32Ty));
901             Args.push_back(Builder.getInt32(ResElts + C->getZExtValue()));
902             Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
903 
904             LHS = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
905             RHS = EI->getVectorOperand();
906             VIsUndefShuffle = false;
907           }
908           if (!Args.empty()) {
909             llvm::Constant *Mask = llvm::ConstantVector::get(Args);
910             V = Builder.CreateShuffleVector(LHS, RHS, Mask);
911             ++CurIdx;
912             continue;
913           }
914         }
915       }
916       V = Builder.CreateInsertElement(V, Init, Builder.getInt32(CurIdx),
917                                       "vecinit");
918       VIsUndefShuffle = false;
919       ++CurIdx;
920       continue;
921     }
922 
923     unsigned InitElts = VVT->getNumElements();
924 
925     // If the initializer is an ExtVecEltExpr (a swizzle), and the swizzle's
926     // input is the same width as the vector being constructed, generate an
927     // optimized shuffle of the swizzle input into the result.
928     unsigned Offset = (CurIdx == 0) ? 0 : ResElts;
929     if (isa<ExtVectorElementExpr>(IE)) {
930       llvm::ShuffleVectorInst *SVI = cast<llvm::ShuffleVectorInst>(Init);
931       Value *SVOp = SVI->getOperand(0);
932       llvm::VectorType *OpTy = cast<llvm::VectorType>(SVOp->getType());
933 
934       if (OpTy->getNumElements() == ResElts) {
935         for (unsigned j = 0; j != CurIdx; ++j) {
936           // If the current vector initializer is a shuffle with undef, merge
937           // this shuffle directly into it.
938           if (VIsUndefShuffle) {
939             Args.push_back(getMaskElt(cast<llvm::ShuffleVectorInst>(V), j, 0,
940                                       CGF.Int32Ty));
941           } else {
942             Args.push_back(Builder.getInt32(j));
943           }
944         }
945         for (unsigned j = 0, je = InitElts; j != je; ++j)
946           Args.push_back(getMaskElt(SVI, j, Offset, CGF.Int32Ty));
947         Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
948 
949         if (VIsUndefShuffle)
950           V = cast<llvm::ShuffleVectorInst>(V)->getOperand(0);
951 
952         Init = SVOp;
953       }
954     }
955 
956     // Extend init to result vector length, and then shuffle its contribution
957     // to the vector initializer into V.
958     if (Args.empty()) {
959       for (unsigned j = 0; j != InitElts; ++j)
960         Args.push_back(Builder.getInt32(j));
961       Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
962       llvm::Constant *Mask = llvm::ConstantVector::get(Args);
963       Init = Builder.CreateShuffleVector(Init, llvm::UndefValue::get(VVT),
964                                          Mask, "vext");
965 
966       Args.clear();
967       for (unsigned j = 0; j != CurIdx; ++j)
968         Args.push_back(Builder.getInt32(j));
969       for (unsigned j = 0; j != InitElts; ++j)
970         Args.push_back(Builder.getInt32(j+Offset));
971       Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
972     }
973 
974     // If V is undef, make sure it ends up on the RHS of the shuffle to aid
975     // merging subsequent shuffles into this one.
976     if (CurIdx == 0)
977       std::swap(V, Init);
978     llvm::Constant *Mask = llvm::ConstantVector::get(Args);
979     V = Builder.CreateShuffleVector(V, Init, Mask, "vecinit");
980     VIsUndefShuffle = isa<llvm::UndefValue>(Init);
981     CurIdx += InitElts;
982   }
983 
984   // FIXME: evaluate codegen vs. shuffling against constant null vector.
985   // Emit remaining default initializers.
986   llvm::Type *EltTy = VType->getElementType();
987 
988   // Emit remaining default initializers
989   for (/* Do not initialize i*/; CurIdx < ResElts; ++CurIdx) {
990     Value *Idx = Builder.getInt32(CurIdx);
991     llvm::Value *Init = llvm::Constant::getNullValue(EltTy);
992     V = Builder.CreateInsertElement(V, Init, Idx, "vecinit");
993   }
994   return V;
995 }
996 
ShouldNullCheckClassCastValue(const CastExpr * CE)997 static bool ShouldNullCheckClassCastValue(const CastExpr *CE) {
998   const Expr *E = CE->getSubExpr();
999 
1000   if (CE->getCastKind() == CK_UncheckedDerivedToBase)
1001     return false;
1002 
1003   if (isa<CXXThisExpr>(E)) {
1004     // We always assume that 'this' is never null.
1005     return false;
1006   }
1007 
1008   if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(CE)) {
1009     // And that glvalue casts are never null.
1010     if (ICE->getValueKind() != VK_RValue)
1011       return false;
1012   }
1013 
1014   return true;
1015 }
1016 
1017 // VisitCastExpr - Emit code for an explicit or implicit cast.  Implicit casts
1018 // have to handle a more broad range of conversions than explicit casts, as they
1019 // handle things like function to ptr-to-function decay etc.
VisitCastExpr(CastExpr * CE)1020 Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
1021   Expr *E = CE->getSubExpr();
1022   QualType DestTy = CE->getType();
1023   CastKind Kind = CE->getCastKind();
1024 
1025   if (!DestTy->isVoidType())
1026     TestAndClearIgnoreResultAssign();
1027 
1028   // Since almost all cast kinds apply to scalars, this switch doesn't have
1029   // a default case, so the compiler will warn on a missing case.  The cases
1030   // are in the same order as in the CastKind enum.
1031   switch (Kind) {
1032   case CK_Dependent: llvm_unreachable("dependent cast kind in IR gen!");
1033   case CK_BuiltinFnToFnPtr:
1034     llvm_unreachable("builtin functions are handled elsewhere");
1035 
1036   case CK_LValueBitCast:
1037   case CK_ObjCObjectLValueCast: {
1038     Value *V = EmitLValue(E).getAddress();
1039     V = Builder.CreateBitCast(V,
1040                           ConvertType(CGF.getContext().getPointerType(DestTy)));
1041     return EmitLoadOfLValue(CGF.MakeNaturalAlignAddrLValue(V, DestTy));
1042   }
1043 
1044   case CK_CPointerToObjCPointerCast:
1045   case CK_BlockPointerToObjCPointerCast:
1046   case CK_AnyPointerToBlockPointerCast:
1047   case CK_BitCast: {
1048     Value *Src = Visit(const_cast<Expr*>(E));
1049     return Builder.CreateBitCast(Src, ConvertType(DestTy));
1050   }
1051   case CK_AtomicToNonAtomic:
1052   case CK_NonAtomicToAtomic:
1053   case CK_NoOp:
1054   case CK_UserDefinedConversion:
1055     return Visit(const_cast<Expr*>(E));
1056 
1057   case CK_BaseToDerived: {
1058     const CXXRecordDecl *DerivedClassDecl =
1059       DestTy->getCXXRecordDeclForPointerType();
1060 
1061     return CGF.GetAddressOfDerivedClass(Visit(E), DerivedClassDecl,
1062                                         CE->path_begin(), CE->path_end(),
1063                                         ShouldNullCheckClassCastValue(CE));
1064   }
1065   case CK_UncheckedDerivedToBase:
1066   case CK_DerivedToBase: {
1067     const RecordType *DerivedClassTy =
1068       E->getType()->getAs<PointerType>()->getPointeeType()->getAs<RecordType>();
1069     CXXRecordDecl *DerivedClassDecl =
1070       cast<CXXRecordDecl>(DerivedClassTy->getDecl());
1071 
1072     return CGF.GetAddressOfBaseClass(Visit(E), DerivedClassDecl,
1073                                      CE->path_begin(), CE->path_end(),
1074                                      ShouldNullCheckClassCastValue(CE));
1075   }
1076   case CK_Dynamic: {
1077     Value *V = Visit(const_cast<Expr*>(E));
1078     const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(CE);
1079     return CGF.EmitDynamicCast(V, DCE);
1080   }
1081 
1082   case CK_ArrayToPointerDecay: {
1083     assert(E->getType()->isArrayType() &&
1084            "Array to pointer decay must have array source type!");
1085 
1086     Value *V = EmitLValue(E).getAddress();  // Bitfields can't be arrays.
1087 
1088     // Note that VLA pointers are always decayed, so we don't need to do
1089     // anything here.
1090     if (!E->getType()->isVariableArrayType()) {
1091       assert(isa<llvm::PointerType>(V->getType()) && "Expected pointer");
1092       assert(isa<llvm::ArrayType>(cast<llvm::PointerType>(V->getType())
1093                                  ->getElementType()) &&
1094              "Expected pointer to array");
1095       V = Builder.CreateStructGEP(V, 0, "arraydecay");
1096     }
1097 
1098     // Make sure the array decay ends up being the right type.  This matters if
1099     // the array type was of an incomplete type.
1100     return CGF.Builder.CreateBitCast(V, ConvertType(CE->getType()));
1101   }
1102   case CK_FunctionToPointerDecay:
1103     return EmitLValue(E).getAddress();
1104 
1105   case CK_NullToPointer:
1106     if (MustVisitNullValue(E))
1107       (void) Visit(E);
1108 
1109     return llvm::ConstantPointerNull::get(
1110                                cast<llvm::PointerType>(ConvertType(DestTy)));
1111 
1112   case CK_NullToMemberPointer: {
1113     if (MustVisitNullValue(E))
1114       (void) Visit(E);
1115 
1116     const MemberPointerType *MPT = CE->getType()->getAs<MemberPointerType>();
1117     return CGF.CGM.getCXXABI().EmitNullMemberPointer(MPT);
1118   }
1119 
1120   case CK_ReinterpretMemberPointer:
1121   case CK_BaseToDerivedMemberPointer:
1122   case CK_DerivedToBaseMemberPointer: {
1123     Value *Src = Visit(E);
1124 
1125     // Note that the AST doesn't distinguish between checked and
1126     // unchecked member pointer conversions, so we always have to
1127     // implement checked conversions here.  This is inefficient when
1128     // actual control flow may be required in order to perform the
1129     // check, which it is for data member pointers (but not member
1130     // function pointers on Itanium and ARM).
1131     return CGF.CGM.getCXXABI().EmitMemberPointerConversion(CGF, CE, Src);
1132   }
1133 
1134   case CK_ARCProduceObject:
1135     return CGF.EmitARCRetainScalarExpr(E);
1136   case CK_ARCConsumeObject:
1137     return CGF.EmitObjCConsumeObject(E->getType(), Visit(E));
1138   case CK_ARCReclaimReturnedObject: {
1139     llvm::Value *value = Visit(E);
1140     value = CGF.EmitARCRetainAutoreleasedReturnValue(value);
1141     return CGF.EmitObjCConsumeObject(E->getType(), value);
1142   }
1143   case CK_ARCExtendBlockObject:
1144     return CGF.EmitARCExtendBlockObject(E);
1145 
1146   case CK_CopyAndAutoreleaseBlockObject:
1147     return CGF.EmitBlockCopyAndAutorelease(Visit(E), E->getType());
1148 
1149   case CK_FloatingRealToComplex:
1150   case CK_FloatingComplexCast:
1151   case CK_IntegralRealToComplex:
1152   case CK_IntegralComplexCast:
1153   case CK_IntegralComplexToFloatingComplex:
1154   case CK_FloatingComplexToIntegralComplex:
1155   case CK_ConstructorConversion:
1156   case CK_ToUnion:
1157     llvm_unreachable("scalar cast to non-scalar value");
1158 
1159   case CK_LValueToRValue:
1160     assert(CGF.getContext().hasSameUnqualifiedType(E->getType(), DestTy));
1161     assert(E->isGLValue() && "lvalue-to-rvalue applied to r-value!");
1162     return Visit(const_cast<Expr*>(E));
1163 
1164   case CK_IntegralToPointer: {
1165     Value *Src = Visit(const_cast<Expr*>(E));
1166 
1167     // First, convert to the correct width so that we control the kind of
1168     // extension.
1169     llvm::Type *MiddleTy = CGF.IntPtrTy;
1170     bool InputSigned = E->getType()->isSignedIntegerOrEnumerationType();
1171     llvm::Value* IntResult =
1172       Builder.CreateIntCast(Src, MiddleTy, InputSigned, "conv");
1173 
1174     return Builder.CreateIntToPtr(IntResult, ConvertType(DestTy));
1175   }
1176   case CK_PointerToIntegral:
1177     assert(!DestTy->isBooleanType() && "bool should use PointerToBool");
1178     return Builder.CreatePtrToInt(Visit(E), ConvertType(DestTy));
1179 
1180   case CK_ToVoid: {
1181     CGF.EmitIgnoredExpr(E);
1182     return 0;
1183   }
1184   case CK_VectorSplat: {
1185     llvm::Type *DstTy = ConvertType(DestTy);
1186     Value *Elt = Visit(const_cast<Expr*>(E));
1187     Elt = EmitScalarConversion(Elt, E->getType(),
1188                                DestTy->getAs<VectorType>()->getElementType());
1189 
1190     // Insert the element in element zero of an undef vector
1191     llvm::Value *UnV = llvm::UndefValue::get(DstTy);
1192     llvm::Value *Idx = Builder.getInt32(0);
1193     UnV = Builder.CreateInsertElement(UnV, Elt, Idx);
1194 
1195     // Splat the element across to all elements
1196     unsigned NumElements = cast<llvm::VectorType>(DstTy)->getNumElements();
1197     llvm::Constant *Zero = Builder.getInt32(0);
1198     llvm::Constant *Mask = llvm::ConstantVector::getSplat(NumElements, Zero);
1199     llvm::Value *Yay = Builder.CreateShuffleVector(UnV, UnV, Mask, "splat");
1200     return Yay;
1201   }
1202 
1203   case CK_IntegralCast:
1204   case CK_IntegralToFloating:
1205   case CK_FloatingToIntegral:
1206   case CK_FloatingCast:
1207     return EmitScalarConversion(Visit(E), E->getType(), DestTy);
1208   case CK_IntegralToBoolean:
1209     return EmitIntToBoolConversion(Visit(E));
1210   case CK_PointerToBoolean:
1211     return EmitPointerToBoolConversion(Visit(E));
1212   case CK_FloatingToBoolean:
1213     return EmitFloatToBoolConversion(Visit(E));
1214   case CK_MemberPointerToBoolean: {
1215     llvm::Value *MemPtr = Visit(E);
1216     const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>();
1217     return CGF.CGM.getCXXABI().EmitMemberPointerIsNotNull(CGF, MemPtr, MPT);
1218   }
1219 
1220   case CK_FloatingComplexToReal:
1221   case CK_IntegralComplexToReal:
1222     return CGF.EmitComplexExpr(E, false, true).first;
1223 
1224   case CK_FloatingComplexToBoolean:
1225   case CK_IntegralComplexToBoolean: {
1226     CodeGenFunction::ComplexPairTy V = CGF.EmitComplexExpr(E);
1227 
1228     // TODO: kill this function off, inline appropriate case here
1229     return EmitComplexToScalarConversion(V, E->getType(), DestTy);
1230   }
1231 
1232   }
1233 
1234   llvm_unreachable("unknown scalar cast");
1235 }
1236 
VisitStmtExpr(const StmtExpr * E)1237 Value *ScalarExprEmitter::VisitStmtExpr(const StmtExpr *E) {
1238   CodeGenFunction::StmtExprEvaluation eval(CGF);
1239   return CGF.EmitCompoundStmt(*E->getSubStmt(), !E->getType()->isVoidType())
1240     .getScalarVal();
1241 }
1242 
1243 //===----------------------------------------------------------------------===//
1244 //                             Unary Operators
1245 //===----------------------------------------------------------------------===//
1246 
1247 llvm::Value *ScalarExprEmitter::
EmitAddConsiderOverflowBehavior(const UnaryOperator * E,llvm::Value * InVal,llvm::Value * NextVal,bool IsInc)1248 EmitAddConsiderOverflowBehavior(const UnaryOperator *E,
1249                                 llvm::Value *InVal,
1250                                 llvm::Value *NextVal, bool IsInc) {
1251   switch (CGF.getContext().getLangOpts().getSignedOverflowBehavior()) {
1252   case LangOptions::SOB_Defined:
1253     return Builder.CreateAdd(InVal, NextVal, IsInc ? "inc" : "dec");
1254   case LangOptions::SOB_Undefined:
1255     if (!CGF.CatchUndefined)
1256       return Builder.CreateNSWAdd(InVal, NextVal, IsInc ? "inc" : "dec");
1257     // Fall through.
1258   case LangOptions::SOB_Trapping:
1259     BinOpInfo BinOp;
1260     BinOp.LHS = InVal;
1261     BinOp.RHS = NextVal;
1262     BinOp.Ty = E->getType();
1263     BinOp.Opcode = BO_Add;
1264     BinOp.E = E;
1265     return EmitOverflowCheckedBinOp(BinOp);
1266   }
1267   llvm_unreachable("Unknown SignedOverflowBehaviorTy");
1268 }
1269 
1270 llvm::Value *
EmitScalarPrePostIncDec(const UnaryOperator * E,LValue LV,bool isInc,bool isPre)1271 ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
1272                                            bool isInc, bool isPre) {
1273 
1274   QualType type = E->getSubExpr()->getType();
1275   llvm::Value *value = EmitLoadOfLValue(LV);
1276   llvm::Value *input = value;
1277   llvm::PHINode *atomicPHI = 0;
1278 
1279   int amount = (isInc ? 1 : -1);
1280 
1281   if (const AtomicType *atomicTy = type->getAs<AtomicType>()) {
1282     llvm::BasicBlock *startBB = Builder.GetInsertBlock();
1283     llvm::BasicBlock *opBB = CGF.createBasicBlock("atomic_op", CGF.CurFn);
1284     Builder.CreateBr(opBB);
1285     Builder.SetInsertPoint(opBB);
1286     atomicPHI = Builder.CreatePHI(value->getType(), 2);
1287     atomicPHI->addIncoming(value, startBB);
1288     type = atomicTy->getValueType();
1289     value = atomicPHI;
1290   }
1291 
1292   // Special case of integer increment that we have to check first: bool++.
1293   // Due to promotion rules, we get:
1294   //   bool++ -> bool = bool + 1
1295   //          -> bool = (int)bool + 1
1296   //          -> bool = ((int)bool + 1 != 0)
1297   // An interesting aspect of this is that increment is always true.
1298   // Decrement does not have this property.
1299   if (isInc && type->isBooleanType()) {
1300     value = Builder.getTrue();
1301 
1302   // Most common case by far: integer increment.
1303   } else if (type->isIntegerType()) {
1304 
1305     llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount, true);
1306 
1307     // Note that signed integer inc/dec with width less than int can't
1308     // overflow because of promotion rules; we're just eliding a few steps here.
1309     if (type->isSignedIntegerOrEnumerationType() &&
1310         value->getType()->getPrimitiveSizeInBits() >=
1311             CGF.IntTy->getBitWidth())
1312       value = EmitAddConsiderOverflowBehavior(E, value, amt, isInc);
1313     else
1314       value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
1315 
1316   // Next most common: pointer increment.
1317   } else if (const PointerType *ptr = type->getAs<PointerType>()) {
1318     QualType type = ptr->getPointeeType();
1319 
1320     // VLA types don't have constant size.
1321     if (const VariableArrayType *vla
1322           = CGF.getContext().getAsVariableArrayType(type)) {
1323       llvm::Value *numElts = CGF.getVLASize(vla).first;
1324       if (!isInc) numElts = Builder.CreateNSWNeg(numElts, "vla.negsize");
1325       if (CGF.getContext().getLangOpts().isSignedOverflowDefined())
1326         value = Builder.CreateGEP(value, numElts, "vla.inc");
1327       else
1328         value = Builder.CreateInBoundsGEP(value, numElts, "vla.inc");
1329 
1330     // Arithmetic on function pointers (!) is just +-1.
1331     } else if (type->isFunctionType()) {
1332       llvm::Value *amt = Builder.getInt32(amount);
1333 
1334       value = CGF.EmitCastToVoidPtr(value);
1335       if (CGF.getContext().getLangOpts().isSignedOverflowDefined())
1336         value = Builder.CreateGEP(value, amt, "incdec.funcptr");
1337       else
1338         value = Builder.CreateInBoundsGEP(value, amt, "incdec.funcptr");
1339       value = Builder.CreateBitCast(value, input->getType());
1340 
1341     // For everything else, we can just do a simple increment.
1342     } else {
1343       llvm::Value *amt = Builder.getInt32(amount);
1344       if (CGF.getContext().getLangOpts().isSignedOverflowDefined())
1345         value = Builder.CreateGEP(value, amt, "incdec.ptr");
1346       else
1347         value = Builder.CreateInBoundsGEP(value, amt, "incdec.ptr");
1348     }
1349 
1350   // Vector increment/decrement.
1351   } else if (type->isVectorType()) {
1352     if (type->hasIntegerRepresentation()) {
1353       llvm::Value *amt = llvm::ConstantInt::get(value->getType(), amount);
1354 
1355       value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
1356     } else {
1357       value = Builder.CreateFAdd(
1358                   value,
1359                   llvm::ConstantFP::get(value->getType(), amount),
1360                   isInc ? "inc" : "dec");
1361     }
1362 
1363   // Floating point.
1364   } else if (type->isRealFloatingType()) {
1365     // Add the inc/dec to the real part.
1366     llvm::Value *amt;
1367 
1368     if (type->isHalfType()) {
1369       // Another special case: half FP increment should be done via float
1370       value =
1371     Builder.CreateCall(CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_from_fp16),
1372                        input);
1373     }
1374 
1375     if (value->getType()->isFloatTy())
1376       amt = llvm::ConstantFP::get(VMContext,
1377                                   llvm::APFloat(static_cast<float>(amount)));
1378     else if (value->getType()->isDoubleTy())
1379       amt = llvm::ConstantFP::get(VMContext,
1380                                   llvm::APFloat(static_cast<double>(amount)));
1381     else {
1382       llvm::APFloat F(static_cast<float>(amount));
1383       bool ignored;
1384       F.convert(CGF.Target.getLongDoubleFormat(), llvm::APFloat::rmTowardZero,
1385                 &ignored);
1386       amt = llvm::ConstantFP::get(VMContext, F);
1387     }
1388     value = Builder.CreateFAdd(value, amt, isInc ? "inc" : "dec");
1389 
1390     if (type->isHalfType())
1391       value =
1392        Builder.CreateCall(CGF.CGM.getIntrinsic(llvm::Intrinsic::convert_to_fp16),
1393                           value);
1394 
1395   // Objective-C pointer types.
1396   } else {
1397     const ObjCObjectPointerType *OPT = type->castAs<ObjCObjectPointerType>();
1398     value = CGF.EmitCastToVoidPtr(value);
1399 
1400     CharUnits size = CGF.getContext().getTypeSizeInChars(OPT->getObjectType());
1401     if (!isInc) size = -size;
1402     llvm::Value *sizeValue =
1403       llvm::ConstantInt::get(CGF.SizeTy, size.getQuantity());
1404 
1405     if (CGF.getContext().getLangOpts().isSignedOverflowDefined())
1406       value = Builder.CreateGEP(value, sizeValue, "incdec.objptr");
1407     else
1408       value = Builder.CreateInBoundsGEP(value, sizeValue, "incdec.objptr");
1409     value = Builder.CreateBitCast(value, input->getType());
1410   }
1411 
1412   if (atomicPHI) {
1413     llvm::BasicBlock *opBB = Builder.GetInsertBlock();
1414     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
1415     llvm::Value *old = Builder.CreateAtomicCmpXchg(LV.getAddress(), atomicPHI,
1416         value, llvm::SequentiallyConsistent);
1417     atomicPHI->addIncoming(old, opBB);
1418     llvm::Value *success = Builder.CreateICmpEQ(old, atomicPHI);
1419     Builder.CreateCondBr(success, contBB, opBB);
1420     Builder.SetInsertPoint(contBB);
1421     return isPre ? value : input;
1422   }
1423 
1424   // Store the updated result through the lvalue.
1425   if (LV.isBitField())
1426     CGF.EmitStoreThroughBitfieldLValue(RValue::get(value), LV, &value);
1427   else
1428     CGF.EmitStoreThroughLValue(RValue::get(value), LV);
1429 
1430   // If this is a postinc, return the value read from memory, otherwise use the
1431   // updated value.
1432   return isPre ? value : input;
1433 }
1434 
1435 
1436 
VisitUnaryMinus(const UnaryOperator * E)1437 Value *ScalarExprEmitter::VisitUnaryMinus(const UnaryOperator *E) {
1438   TestAndClearIgnoreResultAssign();
1439   // Emit unary minus with EmitSub so we handle overflow cases etc.
1440   BinOpInfo BinOp;
1441   BinOp.RHS = Visit(E->getSubExpr());
1442 
1443   if (BinOp.RHS->getType()->isFPOrFPVectorTy())
1444     BinOp.LHS = llvm::ConstantFP::getZeroValueForNegation(BinOp.RHS->getType());
1445   else
1446     BinOp.LHS = llvm::Constant::getNullValue(BinOp.RHS->getType());
1447   BinOp.Ty = E->getType();
1448   BinOp.Opcode = BO_Sub;
1449   BinOp.E = E;
1450   return EmitSub(BinOp);
1451 }
1452 
VisitUnaryNot(const UnaryOperator * E)1453 Value *ScalarExprEmitter::VisitUnaryNot(const UnaryOperator *E) {
1454   TestAndClearIgnoreResultAssign();
1455   Value *Op = Visit(E->getSubExpr());
1456   return Builder.CreateNot(Op, "neg");
1457 }
1458 
VisitUnaryLNot(const UnaryOperator * E)1459 Value *ScalarExprEmitter::VisitUnaryLNot(const UnaryOperator *E) {
1460 
1461   // Perform vector logical not on comparison with zero vector.
1462   if (E->getType()->isExtVectorType()) {
1463     Value *Oper = Visit(E->getSubExpr());
1464     Value *Zero = llvm::Constant::getNullValue(Oper->getType());
1465     Value *Result = Builder.CreateICmp(llvm::CmpInst::ICMP_EQ, Oper, Zero, "cmp");
1466     return Builder.CreateSExt(Result, ConvertType(E->getType()), "sext");
1467   }
1468 
1469   // Compare operand to zero.
1470   Value *BoolVal = CGF.EvaluateExprAsBool(E->getSubExpr());
1471 
1472   // Invert value.
1473   // TODO: Could dynamically modify easy computations here.  For example, if
1474   // the operand is an icmp ne, turn into icmp eq.
1475   BoolVal = Builder.CreateNot(BoolVal, "lnot");
1476 
1477   // ZExt result to the expr type.
1478   return Builder.CreateZExt(BoolVal, ConvertType(E->getType()), "lnot.ext");
1479 }
1480 
VisitOffsetOfExpr(OffsetOfExpr * E)1481 Value *ScalarExprEmitter::VisitOffsetOfExpr(OffsetOfExpr *E) {
1482   // Try folding the offsetof to a constant.
1483   llvm::APSInt Value;
1484   if (E->EvaluateAsInt(Value, CGF.getContext()))
1485     return Builder.getInt(Value);
1486 
1487   // Loop over the components of the offsetof to compute the value.
1488   unsigned n = E->getNumComponents();
1489   llvm::Type* ResultType = ConvertType(E->getType());
1490   llvm::Value* Result = llvm::Constant::getNullValue(ResultType);
1491   QualType CurrentType = E->getTypeSourceInfo()->getType();
1492   for (unsigned i = 0; i != n; ++i) {
1493     OffsetOfExpr::OffsetOfNode ON = E->getComponent(i);
1494     llvm::Value *Offset = 0;
1495     switch (ON.getKind()) {
1496     case OffsetOfExpr::OffsetOfNode::Array: {
1497       // Compute the index
1498       Expr *IdxExpr = E->getIndexExpr(ON.getArrayExprIndex());
1499       llvm::Value* Idx = CGF.EmitScalarExpr(IdxExpr);
1500       bool IdxSigned = IdxExpr->getType()->isSignedIntegerOrEnumerationType();
1501       Idx = Builder.CreateIntCast(Idx, ResultType, IdxSigned, "conv");
1502 
1503       // Save the element type
1504       CurrentType =
1505           CGF.getContext().getAsArrayType(CurrentType)->getElementType();
1506 
1507       // Compute the element size
1508       llvm::Value* ElemSize = llvm::ConstantInt::get(ResultType,
1509           CGF.getContext().getTypeSizeInChars(CurrentType).getQuantity());
1510 
1511       // Multiply out to compute the result
1512       Offset = Builder.CreateMul(Idx, ElemSize);
1513       break;
1514     }
1515 
1516     case OffsetOfExpr::OffsetOfNode::Field: {
1517       FieldDecl *MemberDecl = ON.getField();
1518       RecordDecl *RD = CurrentType->getAs<RecordType>()->getDecl();
1519       const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD);
1520 
1521       // Compute the index of the field in its parent.
1522       unsigned i = 0;
1523       // FIXME: It would be nice if we didn't have to loop here!
1524       for (RecordDecl::field_iterator Field = RD->field_begin(),
1525                                       FieldEnd = RD->field_end();
1526            Field != FieldEnd; ++Field, ++i) {
1527         if (*Field == MemberDecl)
1528           break;
1529       }
1530       assert(i < RL.getFieldCount() && "offsetof field in wrong type");
1531 
1532       // Compute the offset to the field
1533       int64_t OffsetInt = RL.getFieldOffset(i) /
1534                           CGF.getContext().getCharWidth();
1535       Offset = llvm::ConstantInt::get(ResultType, OffsetInt);
1536 
1537       // Save the element type.
1538       CurrentType = MemberDecl->getType();
1539       break;
1540     }
1541 
1542     case OffsetOfExpr::OffsetOfNode::Identifier:
1543       llvm_unreachable("dependent __builtin_offsetof");
1544 
1545     case OffsetOfExpr::OffsetOfNode::Base: {
1546       if (ON.getBase()->isVirtual()) {
1547         CGF.ErrorUnsupported(E, "virtual base in offsetof");
1548         continue;
1549       }
1550 
1551       RecordDecl *RD = CurrentType->getAs<RecordType>()->getDecl();
1552       const ASTRecordLayout &RL = CGF.getContext().getASTRecordLayout(RD);
1553 
1554       // Save the element type.
1555       CurrentType = ON.getBase()->getType();
1556 
1557       // Compute the offset to the base.
1558       const RecordType *BaseRT = CurrentType->getAs<RecordType>();
1559       CXXRecordDecl *BaseRD = cast<CXXRecordDecl>(BaseRT->getDecl());
1560       CharUnits OffsetInt = RL.getBaseClassOffset(BaseRD);
1561       Offset = llvm::ConstantInt::get(ResultType, OffsetInt.getQuantity());
1562       break;
1563     }
1564     }
1565     Result = Builder.CreateAdd(Result, Offset);
1566   }
1567   return Result;
1568 }
1569 
1570 /// VisitUnaryExprOrTypeTraitExpr - Return the size or alignment of the type of
1571 /// argument of the sizeof expression as an integer.
1572 Value *
VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr * E)1573 ScalarExprEmitter::VisitUnaryExprOrTypeTraitExpr(
1574                               const UnaryExprOrTypeTraitExpr *E) {
1575   QualType TypeToSize = E->getTypeOfArgument();
1576   if (E->getKind() == UETT_SizeOf) {
1577     if (const VariableArrayType *VAT =
1578           CGF.getContext().getAsVariableArrayType(TypeToSize)) {
1579       if (E->isArgumentType()) {
1580         // sizeof(type) - make sure to emit the VLA size.
1581         CGF.EmitVariablyModifiedType(TypeToSize);
1582       } else {
1583         // C99 6.5.3.4p2: If the argument is an expression of type
1584         // VLA, it is evaluated.
1585         CGF.EmitIgnoredExpr(E->getArgumentExpr());
1586       }
1587 
1588       QualType eltType;
1589       llvm::Value *numElts;
1590       llvm::tie(numElts, eltType) = CGF.getVLASize(VAT);
1591 
1592       llvm::Value *size = numElts;
1593 
1594       // Scale the number of non-VLA elements by the non-VLA element size.
1595       CharUnits eltSize = CGF.getContext().getTypeSizeInChars(eltType);
1596       if (!eltSize.isOne())
1597         size = CGF.Builder.CreateNUWMul(CGF.CGM.getSize(eltSize), numElts);
1598 
1599       return size;
1600     }
1601   }
1602 
1603   // If this isn't sizeof(vla), the result must be constant; use the constant
1604   // folding logic so we don't have to duplicate it here.
1605   return Builder.getInt(E->EvaluateKnownConstInt(CGF.getContext()));
1606 }
1607 
VisitUnaryReal(const UnaryOperator * E)1608 Value *ScalarExprEmitter::VisitUnaryReal(const UnaryOperator *E) {
1609   Expr *Op = E->getSubExpr();
1610   if (Op->getType()->isAnyComplexType()) {
1611     // If it's an l-value, load through the appropriate subobject l-value.
1612     // Note that we have to ask E because Op might be an l-value that
1613     // this won't work for, e.g. an Obj-C property.
1614     if (E->isGLValue())
1615       return CGF.EmitLoadOfLValue(CGF.EmitLValue(E)).getScalarVal();
1616 
1617     // Otherwise, calculate and project.
1618     return CGF.EmitComplexExpr(Op, false, true).first;
1619   }
1620 
1621   return Visit(Op);
1622 }
1623 
VisitUnaryImag(const UnaryOperator * E)1624 Value *ScalarExprEmitter::VisitUnaryImag(const UnaryOperator *E) {
1625   Expr *Op = E->getSubExpr();
1626   if (Op->getType()->isAnyComplexType()) {
1627     // If it's an l-value, load through the appropriate subobject l-value.
1628     // Note that we have to ask E because Op might be an l-value that
1629     // this won't work for, e.g. an Obj-C property.
1630     if (Op->isGLValue())
1631       return CGF.EmitLoadOfLValue(CGF.EmitLValue(E)).getScalarVal();
1632 
1633     // Otherwise, calculate and project.
1634     return CGF.EmitComplexExpr(Op, true, false).second;
1635   }
1636 
1637   // __imag on a scalar returns zero.  Emit the subexpr to ensure side
1638   // effects are evaluated, but not the actual value.
1639   if (Op->isGLValue())
1640     CGF.EmitLValue(Op);
1641   else
1642     CGF.EmitScalarExpr(Op, true);
1643   return llvm::Constant::getNullValue(ConvertType(E->getType()));
1644 }
1645 
1646 //===----------------------------------------------------------------------===//
1647 //                           Binary Operators
1648 //===----------------------------------------------------------------------===//
1649 
EmitBinOps(const BinaryOperator * E)1650 BinOpInfo ScalarExprEmitter::EmitBinOps(const BinaryOperator *E) {
1651   TestAndClearIgnoreResultAssign();
1652   BinOpInfo Result;
1653   Result.LHS = Visit(E->getLHS());
1654   Result.RHS = Visit(E->getRHS());
1655   Result.Ty  = E->getType();
1656   Result.Opcode = E->getOpcode();
1657   Result.E = E;
1658   return Result;
1659 }
1660 
EmitCompoundAssignLValue(const CompoundAssignOperator * E,Value * (ScalarExprEmitter::* Func)(const BinOpInfo &),Value * & Result)1661 LValue ScalarExprEmitter::EmitCompoundAssignLValue(
1662                                               const CompoundAssignOperator *E,
1663                         Value *(ScalarExprEmitter::*Func)(const BinOpInfo &),
1664                                                    Value *&Result) {
1665   QualType LHSTy = E->getLHS()->getType();
1666   BinOpInfo OpInfo;
1667 
1668   if (E->getComputationResultType()->isAnyComplexType()) {
1669     // This needs to go through the complex expression emitter, but it's a tad
1670     // complicated to do that... I'm leaving it out for now.  (Note that we do
1671     // actually need the imaginary part of the RHS for multiplication and
1672     // division.)
1673     CGF.ErrorUnsupported(E, "complex compound assignment");
1674     Result = llvm::UndefValue::get(CGF.ConvertType(E->getType()));
1675     return LValue();
1676   }
1677 
1678   // Emit the RHS first.  __block variables need to have the rhs evaluated
1679   // first, plus this should improve codegen a little.
1680   OpInfo.RHS = Visit(E->getRHS());
1681   OpInfo.Ty = E->getComputationResultType();
1682   OpInfo.Opcode = E->getOpcode();
1683   OpInfo.E = E;
1684   // Load/convert the LHS.
1685   LValue LHSLV = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
1686   OpInfo.LHS = EmitLoadOfLValue(LHSLV);
1687 
1688   llvm::PHINode *atomicPHI = 0;
1689   if (LHSTy->isAtomicType()) {
1690     // FIXME: For floating point types, we should be saving and restoring the
1691     // floating point environment in the loop.
1692     llvm::BasicBlock *startBB = Builder.GetInsertBlock();
1693     llvm::BasicBlock *opBB = CGF.createBasicBlock("atomic_op", CGF.CurFn);
1694     Builder.CreateBr(opBB);
1695     Builder.SetInsertPoint(opBB);
1696     atomicPHI = Builder.CreatePHI(OpInfo.LHS->getType(), 2);
1697     atomicPHI->addIncoming(OpInfo.LHS, startBB);
1698     OpInfo.LHS = atomicPHI;
1699   }
1700 
1701   OpInfo.LHS = EmitScalarConversion(OpInfo.LHS, LHSTy,
1702                                     E->getComputationLHSType());
1703 
1704   // Expand the binary operator.
1705   Result = (this->*Func)(OpInfo);
1706 
1707   // Convert the result back to the LHS type.
1708   Result = EmitScalarConversion(Result, E->getComputationResultType(), LHSTy);
1709 
1710   if (atomicPHI) {
1711     llvm::BasicBlock *opBB = Builder.GetInsertBlock();
1712     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
1713     llvm::Value *old = Builder.CreateAtomicCmpXchg(LHSLV.getAddress(), atomicPHI,
1714         Result, llvm::SequentiallyConsistent);
1715     atomicPHI->addIncoming(old, opBB);
1716     llvm::Value *success = Builder.CreateICmpEQ(old, atomicPHI);
1717     Builder.CreateCondBr(success, contBB, opBB);
1718     Builder.SetInsertPoint(contBB);
1719     return LHSLV;
1720   }
1721 
1722   // Store the result value into the LHS lvalue. Bit-fields are handled
1723   // specially because the result is altered by the store, i.e., [C99 6.5.16p1]
1724   // 'An assignment expression has the value of the left operand after the
1725   // assignment...'.
1726   if (LHSLV.isBitField())
1727     CGF.EmitStoreThroughBitfieldLValue(RValue::get(Result), LHSLV, &Result);
1728   else
1729     CGF.EmitStoreThroughLValue(RValue::get(Result), LHSLV);
1730 
1731   return LHSLV;
1732 }
1733 
EmitCompoundAssign(const CompoundAssignOperator * E,Value * (ScalarExprEmitter::* Func)(const BinOpInfo &))1734 Value *ScalarExprEmitter::EmitCompoundAssign(const CompoundAssignOperator *E,
1735                       Value *(ScalarExprEmitter::*Func)(const BinOpInfo &)) {
1736   bool Ignore = TestAndClearIgnoreResultAssign();
1737   Value *RHS;
1738   LValue LHS = EmitCompoundAssignLValue(E, Func, RHS);
1739 
1740   // If the result is clearly ignored, return now.
1741   if (Ignore)
1742     return 0;
1743 
1744   // The result of an assignment in C is the assigned r-value.
1745   if (!CGF.getContext().getLangOpts().CPlusPlus)
1746     return RHS;
1747 
1748   // If the lvalue is non-volatile, return the computed value of the assignment.
1749   if (!LHS.isVolatileQualified())
1750     return RHS;
1751 
1752   // Otherwise, reload the value.
1753   return EmitLoadOfLValue(LHS);
1754 }
1755 
EmitUndefinedBehaviorIntegerDivAndRemCheck(const BinOpInfo & Ops,llvm::Value * Zero,bool isDiv)1756 void ScalarExprEmitter::EmitUndefinedBehaviorIntegerDivAndRemCheck(
1757     const BinOpInfo &Ops, llvm::Value *Zero, bool isDiv) {
1758   llvm::IntegerType *Ty = cast<llvm::IntegerType>(Zero->getType());
1759 
1760   if (Ops.Ty->hasSignedIntegerRepresentation()) {
1761     llvm::Value *IntMin =
1762       Builder.getInt(llvm::APInt::getSignedMinValue(Ty->getBitWidth()));
1763     llvm::Value *NegOne = llvm::ConstantInt::get(Ty, -1ULL);
1764 
1765     llvm::Value *Cond1 = Builder.CreateICmpNE(Ops.RHS, Zero);
1766     llvm::Value *LHSCmp = Builder.CreateICmpNE(Ops.LHS, IntMin);
1767     llvm::Value *RHSCmp = Builder.CreateICmpNE(Ops.RHS, NegOne);
1768     llvm::Value *Cond2 = Builder.CreateOr(LHSCmp, RHSCmp, "or");
1769     CGF.EmitCheck(Builder.CreateAnd(Cond1, Cond2, "and"));
1770   } else {
1771     CGF.EmitCheck(Builder.CreateICmpNE(Ops.RHS, Zero));
1772   }
1773 }
1774 
EmitDiv(const BinOpInfo & Ops)1775 Value *ScalarExprEmitter::EmitDiv(const BinOpInfo &Ops) {
1776   if (isTrapvOverflowBehavior()) {
1777     llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty));
1778 
1779     if (Ops.Ty->isIntegerType())
1780       EmitUndefinedBehaviorIntegerDivAndRemCheck(Ops, Zero, true);
1781     else if (Ops.Ty->isRealFloatingType())
1782       CGF.EmitCheck(Builder.CreateFCmpUNE(Ops.RHS, Zero));
1783   }
1784   if (Ops.LHS->getType()->isFPOrFPVectorTy()) {
1785     llvm::Value *Val = Builder.CreateFDiv(Ops.LHS, Ops.RHS, "div");
1786     if (CGF.getContext().getLangOpts().OpenCL) {
1787       // OpenCL 1.1 7.4: minimum accuracy of single precision / is 2.5ulp
1788       llvm::Type *ValTy = Val->getType();
1789       if (ValTy->isFloatTy() ||
1790           (isa<llvm::VectorType>(ValTy) &&
1791            cast<llvm::VectorType>(ValTy)->getElementType()->isFloatTy()))
1792         CGF.SetFPAccuracy(Val, 2.5);
1793     }
1794     return Val;
1795   }
1796   else if (Ops.Ty->hasUnsignedIntegerRepresentation())
1797     return Builder.CreateUDiv(Ops.LHS, Ops.RHS, "div");
1798   else
1799     return Builder.CreateSDiv(Ops.LHS, Ops.RHS, "div");
1800 }
1801 
EmitRem(const BinOpInfo & Ops)1802 Value *ScalarExprEmitter::EmitRem(const BinOpInfo &Ops) {
1803   // Rem in C can't be a floating point type: C99 6.5.5p2.
1804   if (isTrapvOverflowBehavior()) {
1805     llvm::Value *Zero = llvm::Constant::getNullValue(ConvertType(Ops.Ty));
1806 
1807     if (Ops.Ty->isIntegerType())
1808       EmitUndefinedBehaviorIntegerDivAndRemCheck(Ops, Zero, false);
1809   }
1810 
1811   if (Ops.Ty->hasUnsignedIntegerRepresentation())
1812     return Builder.CreateURem(Ops.LHS, Ops.RHS, "rem");
1813   else
1814     return Builder.CreateSRem(Ops.LHS, Ops.RHS, "rem");
1815 }
1816 
EmitOverflowCheckedBinOp(const BinOpInfo & Ops)1817 Value *ScalarExprEmitter::EmitOverflowCheckedBinOp(const BinOpInfo &Ops) {
1818   unsigned IID;
1819   unsigned OpID = 0;
1820 
1821   switch (Ops.Opcode) {
1822   case BO_Add:
1823   case BO_AddAssign:
1824     OpID = 1;
1825     IID = llvm::Intrinsic::sadd_with_overflow;
1826     break;
1827   case BO_Sub:
1828   case BO_SubAssign:
1829     OpID = 2;
1830     IID = llvm::Intrinsic::ssub_with_overflow;
1831     break;
1832   case BO_Mul:
1833   case BO_MulAssign:
1834     OpID = 3;
1835     IID = llvm::Intrinsic::smul_with_overflow;
1836     break;
1837   default:
1838     llvm_unreachable("Unsupported operation for overflow detection");
1839   }
1840   OpID <<= 1;
1841   OpID |= 1;
1842 
1843   llvm::Type *opTy = CGF.CGM.getTypes().ConvertType(Ops.Ty);
1844 
1845   llvm::Function *intrinsic = CGF.CGM.getIntrinsic(IID, opTy);
1846 
1847   Value *resultAndOverflow = Builder.CreateCall2(intrinsic, Ops.LHS, Ops.RHS);
1848   Value *result = Builder.CreateExtractValue(resultAndOverflow, 0);
1849   Value *overflow = Builder.CreateExtractValue(resultAndOverflow, 1);
1850 
1851   // Handle overflow with llvm.trap if no custom handler has been specified.
1852   const std::string *handlerName =
1853     &CGF.getContext().getLangOpts().OverflowHandler;
1854   if (handlerName->empty()) {
1855     CGF.EmitCheck(Builder.CreateNot(overflow));
1856     return result;
1857   }
1858 
1859   // Branch in case of overflow.
1860   llvm::BasicBlock *initialBB = Builder.GetInsertBlock();
1861   llvm::Function::iterator insertPt = initialBB;
1862   llvm::BasicBlock *continueBB = CGF.createBasicBlock("nooverflow", CGF.CurFn,
1863                                                       llvm::next(insertPt));
1864   llvm::BasicBlock *overflowBB = CGF.createBasicBlock("overflow", CGF.CurFn);
1865 
1866   Builder.CreateCondBr(overflow, overflowBB, continueBB);
1867 
1868   // If an overflow handler is set, then we want to call it and then use its
1869   // result, if it returns.
1870   Builder.SetInsertPoint(overflowBB);
1871 
1872   // Get the overflow handler.
1873   llvm::Type *Int8Ty = CGF.Int8Ty;
1874   llvm::Type *argTypes[] = { CGF.Int64Ty, CGF.Int64Ty, Int8Ty, Int8Ty };
1875   llvm::FunctionType *handlerTy =
1876       llvm::FunctionType::get(CGF.Int64Ty, argTypes, true);
1877   llvm::Value *handler = CGF.CGM.CreateRuntimeFunction(handlerTy, *handlerName);
1878 
1879   // Sign extend the args to 64-bit, so that we can use the same handler for
1880   // all types of overflow.
1881   llvm::Value *lhs = Builder.CreateSExt(Ops.LHS, CGF.Int64Ty);
1882   llvm::Value *rhs = Builder.CreateSExt(Ops.RHS, CGF.Int64Ty);
1883 
1884   // Call the handler with the two arguments, the operation, and the size of
1885   // the result.
1886   llvm::Value *handlerResult = Builder.CreateCall4(handler, lhs, rhs,
1887       Builder.getInt8(OpID),
1888       Builder.getInt8(cast<llvm::IntegerType>(opTy)->getBitWidth()));
1889 
1890   // Truncate the result back to the desired size.
1891   handlerResult = Builder.CreateTrunc(handlerResult, opTy);
1892   Builder.CreateBr(continueBB);
1893 
1894   Builder.SetInsertPoint(continueBB);
1895   llvm::PHINode *phi = Builder.CreatePHI(opTy, 2);
1896   phi->addIncoming(result, initialBB);
1897   phi->addIncoming(handlerResult, overflowBB);
1898 
1899   return phi;
1900 }
1901 
1902 /// Emit pointer + index arithmetic.
emitPointerArithmetic(CodeGenFunction & CGF,const BinOpInfo & op,bool isSubtraction)1903 static Value *emitPointerArithmetic(CodeGenFunction &CGF,
1904                                     const BinOpInfo &op,
1905                                     bool isSubtraction) {
1906   // Must have binary (not unary) expr here.  Unary pointer
1907   // increment/decrement doesn't use this path.
1908   const BinaryOperator *expr = cast<BinaryOperator>(op.E);
1909 
1910   Value *pointer = op.LHS;
1911   Expr *pointerOperand = expr->getLHS();
1912   Value *index = op.RHS;
1913   Expr *indexOperand = expr->getRHS();
1914 
1915   // In a subtraction, the LHS is always the pointer.
1916   if (!isSubtraction && !pointer->getType()->isPointerTy()) {
1917     std::swap(pointer, index);
1918     std::swap(pointerOperand, indexOperand);
1919   }
1920 
1921   unsigned width = cast<llvm::IntegerType>(index->getType())->getBitWidth();
1922   if (width != CGF.PointerWidthInBits) {
1923     // Zero-extend or sign-extend the pointer value according to
1924     // whether the index is signed or not.
1925     bool isSigned = indexOperand->getType()->isSignedIntegerOrEnumerationType();
1926     index = CGF.Builder.CreateIntCast(index, CGF.PtrDiffTy, isSigned,
1927                                       "idx.ext");
1928   }
1929 
1930   // If this is subtraction, negate the index.
1931   if (isSubtraction)
1932     index = CGF.Builder.CreateNeg(index, "idx.neg");
1933 
1934   const PointerType *pointerType
1935     = pointerOperand->getType()->getAs<PointerType>();
1936   if (!pointerType) {
1937     QualType objectType = pointerOperand->getType()
1938                                         ->castAs<ObjCObjectPointerType>()
1939                                         ->getPointeeType();
1940     llvm::Value *objectSize
1941       = CGF.CGM.getSize(CGF.getContext().getTypeSizeInChars(objectType));
1942 
1943     index = CGF.Builder.CreateMul(index, objectSize);
1944 
1945     Value *result = CGF.Builder.CreateBitCast(pointer, CGF.VoidPtrTy);
1946     result = CGF.Builder.CreateGEP(result, index, "add.ptr");
1947     return CGF.Builder.CreateBitCast(result, pointer->getType());
1948   }
1949 
1950   QualType elementType = pointerType->getPointeeType();
1951   if (const VariableArrayType *vla
1952         = CGF.getContext().getAsVariableArrayType(elementType)) {
1953     // The element count here is the total number of non-VLA elements.
1954     llvm::Value *numElements = CGF.getVLASize(vla).first;
1955 
1956     // Effectively, the multiply by the VLA size is part of the GEP.
1957     // GEP indexes are signed, and scaling an index isn't permitted to
1958     // signed-overflow, so we use the same semantics for our explicit
1959     // multiply.  We suppress this if overflow is not undefined behavior.
1960     if (CGF.getLangOpts().isSignedOverflowDefined()) {
1961       index = CGF.Builder.CreateMul(index, numElements, "vla.index");
1962       pointer = CGF.Builder.CreateGEP(pointer, index, "add.ptr");
1963     } else {
1964       index = CGF.Builder.CreateNSWMul(index, numElements, "vla.index");
1965       pointer = CGF.Builder.CreateInBoundsGEP(pointer, index, "add.ptr");
1966     }
1967     return pointer;
1968   }
1969 
1970   // Explicitly handle GNU void* and function pointer arithmetic extensions. The
1971   // GNU void* casts amount to no-ops since our void* type is i8*, but this is
1972   // future proof.
1973   if (elementType->isVoidType() || elementType->isFunctionType()) {
1974     Value *result = CGF.Builder.CreateBitCast(pointer, CGF.VoidPtrTy);
1975     result = CGF.Builder.CreateGEP(result, index, "add.ptr");
1976     return CGF.Builder.CreateBitCast(result, pointer->getType());
1977   }
1978 
1979   if (CGF.getLangOpts().isSignedOverflowDefined())
1980     return CGF.Builder.CreateGEP(pointer, index, "add.ptr");
1981 
1982   return CGF.Builder.CreateInBoundsGEP(pointer, index, "add.ptr");
1983 }
1984 
EmitAdd(const BinOpInfo & op)1985 Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &op) {
1986   if (op.LHS->getType()->isPointerTy() ||
1987       op.RHS->getType()->isPointerTy())
1988     return emitPointerArithmetic(CGF, op, /*subtraction*/ false);
1989 
1990   if (op.Ty->isSignedIntegerOrEnumerationType()) {
1991     switch (CGF.getContext().getLangOpts().getSignedOverflowBehavior()) {
1992     case LangOptions::SOB_Defined:
1993       return Builder.CreateAdd(op.LHS, op.RHS, "add");
1994     case LangOptions::SOB_Undefined:
1995       if (!CGF.CatchUndefined)
1996         return Builder.CreateNSWAdd(op.LHS, op.RHS, "add");
1997       // Fall through.
1998     case LangOptions::SOB_Trapping:
1999       return EmitOverflowCheckedBinOp(op);
2000     }
2001   }
2002 
2003   if (op.LHS->getType()->isFPOrFPVectorTy())
2004     return Builder.CreateFAdd(op.LHS, op.RHS, "add");
2005 
2006   return Builder.CreateAdd(op.LHS, op.RHS, "add");
2007 }
2008 
EmitSub(const BinOpInfo & op)2009 Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) {
2010   // The LHS is always a pointer if either side is.
2011   if (!op.LHS->getType()->isPointerTy()) {
2012     if (op.Ty->isSignedIntegerOrEnumerationType()) {
2013       switch (CGF.getContext().getLangOpts().getSignedOverflowBehavior()) {
2014       case LangOptions::SOB_Defined:
2015         return Builder.CreateSub(op.LHS, op.RHS, "sub");
2016       case LangOptions::SOB_Undefined:
2017         if (!CGF.CatchUndefined)
2018           return Builder.CreateNSWSub(op.LHS, op.RHS, "sub");
2019         // Fall through.
2020       case LangOptions::SOB_Trapping:
2021         return EmitOverflowCheckedBinOp(op);
2022       }
2023     }
2024 
2025     if (op.LHS->getType()->isFPOrFPVectorTy())
2026       return Builder.CreateFSub(op.LHS, op.RHS, "sub");
2027 
2028     return Builder.CreateSub(op.LHS, op.RHS, "sub");
2029   }
2030 
2031   // If the RHS is not a pointer, then we have normal pointer
2032   // arithmetic.
2033   if (!op.RHS->getType()->isPointerTy())
2034     return emitPointerArithmetic(CGF, op, /*subtraction*/ true);
2035 
2036   // Otherwise, this is a pointer subtraction.
2037 
2038   // Do the raw subtraction part.
2039   llvm::Value *LHS
2040     = Builder.CreatePtrToInt(op.LHS, CGF.PtrDiffTy, "sub.ptr.lhs.cast");
2041   llvm::Value *RHS
2042     = Builder.CreatePtrToInt(op.RHS, CGF.PtrDiffTy, "sub.ptr.rhs.cast");
2043   Value *diffInChars = Builder.CreateSub(LHS, RHS, "sub.ptr.sub");
2044 
2045   // Okay, figure out the element size.
2046   const BinaryOperator *expr = cast<BinaryOperator>(op.E);
2047   QualType elementType = expr->getLHS()->getType()->getPointeeType();
2048 
2049   llvm::Value *divisor = 0;
2050 
2051   // For a variable-length array, this is going to be non-constant.
2052   if (const VariableArrayType *vla
2053         = CGF.getContext().getAsVariableArrayType(elementType)) {
2054     llvm::Value *numElements;
2055     llvm::tie(numElements, elementType) = CGF.getVLASize(vla);
2056 
2057     divisor = numElements;
2058 
2059     // Scale the number of non-VLA elements by the non-VLA element size.
2060     CharUnits eltSize = CGF.getContext().getTypeSizeInChars(elementType);
2061     if (!eltSize.isOne())
2062       divisor = CGF.Builder.CreateNUWMul(CGF.CGM.getSize(eltSize), divisor);
2063 
2064   // For everything elese, we can just compute it, safe in the
2065   // assumption that Sema won't let anything through that we can't
2066   // safely compute the size of.
2067   } else {
2068     CharUnits elementSize;
2069     // Handle GCC extension for pointer arithmetic on void* and
2070     // function pointer types.
2071     if (elementType->isVoidType() || elementType->isFunctionType())
2072       elementSize = CharUnits::One();
2073     else
2074       elementSize = CGF.getContext().getTypeSizeInChars(elementType);
2075 
2076     // Don't even emit the divide for element size of 1.
2077     if (elementSize.isOne())
2078       return diffInChars;
2079 
2080     divisor = CGF.CGM.getSize(elementSize);
2081   }
2082 
2083   // Otherwise, do a full sdiv. This uses the "exact" form of sdiv, since
2084   // pointer difference in C is only defined in the case where both operands
2085   // are pointing to elements of an array.
2086   return Builder.CreateExactSDiv(diffInChars, divisor, "sub.ptr.div");
2087 }
2088 
EmitShl(const BinOpInfo & Ops)2089 Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) {
2090   // LLVM requires the LHS and RHS to be the same type: promote or truncate the
2091   // RHS to the same size as the LHS.
2092   Value *RHS = Ops.RHS;
2093   if (Ops.LHS->getType() != RHS->getType())
2094     RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
2095 
2096   if (CGF.CatchUndefined && isa<llvm::IntegerType>(Ops.LHS->getType())) {
2097     unsigned Width = cast<llvm::IntegerType>(Ops.LHS->getType())->getBitWidth();
2098     llvm::Value *WidthMinusOne =
2099       llvm::ConstantInt::get(RHS->getType(), Width - 1);
2100     CGF.EmitCheck(Builder.CreateICmpULE(RHS, WidthMinusOne));
2101 
2102     if (Ops.Ty->hasSignedIntegerRepresentation()) {
2103       // Check whether we are shifting any non-zero bits off the top of the
2104       // integer.
2105       llvm::Value *BitsShiftedOff =
2106         Builder.CreateLShr(Ops.LHS,
2107                            Builder.CreateSub(WidthMinusOne, RHS, "shl.zeros",
2108                                              /*NUW*/true, /*NSW*/true),
2109                            "shl.check");
2110       if (CGF.getLangOpts().CPlusPlus) {
2111         // In C99, we are not permitted to shift a 1 bit into the sign bit.
2112         // Under C++11's rules, shifting a 1 bit into the sign bit is
2113         // OK, but shifting a 1 bit out of it is not. (C89 and C++03 don't
2114         // define signed left shifts, so we use the C99 and C++11 rules there).
2115         llvm::Value *One = llvm::ConstantInt::get(BitsShiftedOff->getType(), 1);
2116         BitsShiftedOff = Builder.CreateLShr(BitsShiftedOff, One);
2117       }
2118       llvm::Value *Zero = llvm::ConstantInt::get(BitsShiftedOff->getType(), 0);
2119       CGF.EmitCheck(Builder.CreateICmpEQ(BitsShiftedOff, Zero));
2120     }
2121   }
2122 
2123   return Builder.CreateShl(Ops.LHS, RHS, "shl");
2124 }
2125 
EmitShr(const BinOpInfo & Ops)2126 Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) {
2127   // LLVM requires the LHS and RHS to be the same type: promote or truncate the
2128   // RHS to the same size as the LHS.
2129   Value *RHS = Ops.RHS;
2130   if (Ops.LHS->getType() != RHS->getType())
2131     RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
2132 
2133   if (CGF.CatchUndefined && isa<llvm::IntegerType>(Ops.LHS->getType())) {
2134     unsigned Width = cast<llvm::IntegerType>(Ops.LHS->getType())->getBitWidth();
2135     llvm::Value *WidthVal = llvm::ConstantInt::get(RHS->getType(), Width);
2136     CGF.EmitCheck(Builder.CreateICmpULT(RHS, WidthVal));
2137   }
2138 
2139   if (Ops.Ty->hasUnsignedIntegerRepresentation())
2140     return Builder.CreateLShr(Ops.LHS, RHS, "shr");
2141   return Builder.CreateAShr(Ops.LHS, RHS, "shr");
2142 }
2143 
2144 enum IntrinsicType { VCMPEQ, VCMPGT };
2145 // return corresponding comparison intrinsic for given vector type
GetIntrinsic(IntrinsicType IT,BuiltinType::Kind ElemKind)2146 static llvm::Intrinsic::ID GetIntrinsic(IntrinsicType IT,
2147                                         BuiltinType::Kind ElemKind) {
2148   switch (ElemKind) {
2149   default: llvm_unreachable("unexpected element type");
2150   case BuiltinType::Char_U:
2151   case BuiltinType::UChar:
2152     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequb_p :
2153                             llvm::Intrinsic::ppc_altivec_vcmpgtub_p;
2154   case BuiltinType::Char_S:
2155   case BuiltinType::SChar:
2156     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequb_p :
2157                             llvm::Intrinsic::ppc_altivec_vcmpgtsb_p;
2158   case BuiltinType::UShort:
2159     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequh_p :
2160                             llvm::Intrinsic::ppc_altivec_vcmpgtuh_p;
2161   case BuiltinType::Short:
2162     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequh_p :
2163                             llvm::Intrinsic::ppc_altivec_vcmpgtsh_p;
2164   case BuiltinType::UInt:
2165   case BuiltinType::ULong:
2166     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequw_p :
2167                             llvm::Intrinsic::ppc_altivec_vcmpgtuw_p;
2168   case BuiltinType::Int:
2169   case BuiltinType::Long:
2170     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpequw_p :
2171                             llvm::Intrinsic::ppc_altivec_vcmpgtsw_p;
2172   case BuiltinType::Float:
2173     return (IT == VCMPEQ) ? llvm::Intrinsic::ppc_altivec_vcmpeqfp_p :
2174                             llvm::Intrinsic::ppc_altivec_vcmpgtfp_p;
2175   }
2176 }
2177 
EmitCompare(const BinaryOperator * E,unsigned UICmpOpc,unsigned SICmpOpc,unsigned FCmpOpc)2178 Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,unsigned UICmpOpc,
2179                                       unsigned SICmpOpc, unsigned FCmpOpc) {
2180   TestAndClearIgnoreResultAssign();
2181   Value *Result;
2182   QualType LHSTy = E->getLHS()->getType();
2183   if (const MemberPointerType *MPT = LHSTy->getAs<MemberPointerType>()) {
2184     assert(E->getOpcode() == BO_EQ ||
2185            E->getOpcode() == BO_NE);
2186     Value *LHS = CGF.EmitScalarExpr(E->getLHS());
2187     Value *RHS = CGF.EmitScalarExpr(E->getRHS());
2188     Result = CGF.CGM.getCXXABI().EmitMemberPointerComparison(
2189                    CGF, LHS, RHS, MPT, E->getOpcode() == BO_NE);
2190   } else if (!LHSTy->isAnyComplexType()) {
2191     Value *LHS = Visit(E->getLHS());
2192     Value *RHS = Visit(E->getRHS());
2193 
2194     // If AltiVec, the comparison results in a numeric type, so we use
2195     // intrinsics comparing vectors and giving 0 or 1 as a result
2196     if (LHSTy->isVectorType() && !E->getType()->isVectorType()) {
2197       // constants for mapping CR6 register bits to predicate result
2198       enum { CR6_EQ=0, CR6_EQ_REV, CR6_LT, CR6_LT_REV } CR6;
2199 
2200       llvm::Intrinsic::ID ID = llvm::Intrinsic::not_intrinsic;
2201 
2202       // in several cases vector arguments order will be reversed
2203       Value *FirstVecArg = LHS,
2204             *SecondVecArg = RHS;
2205 
2206       QualType ElTy = LHSTy->getAs<VectorType>()->getElementType();
2207       const BuiltinType *BTy = ElTy->getAs<BuiltinType>();
2208       BuiltinType::Kind ElementKind = BTy->getKind();
2209 
2210       switch(E->getOpcode()) {
2211       default: llvm_unreachable("is not a comparison operation");
2212       case BO_EQ:
2213         CR6 = CR6_LT;
2214         ID = GetIntrinsic(VCMPEQ, ElementKind);
2215         break;
2216       case BO_NE:
2217         CR6 = CR6_EQ;
2218         ID = GetIntrinsic(VCMPEQ, ElementKind);
2219         break;
2220       case BO_LT:
2221         CR6 = CR6_LT;
2222         ID = GetIntrinsic(VCMPGT, ElementKind);
2223         std::swap(FirstVecArg, SecondVecArg);
2224         break;
2225       case BO_GT:
2226         CR6 = CR6_LT;
2227         ID = GetIntrinsic(VCMPGT, ElementKind);
2228         break;
2229       case BO_LE:
2230         if (ElementKind == BuiltinType::Float) {
2231           CR6 = CR6_LT;
2232           ID = llvm::Intrinsic::ppc_altivec_vcmpgefp_p;
2233           std::swap(FirstVecArg, SecondVecArg);
2234         }
2235         else {
2236           CR6 = CR6_EQ;
2237           ID = GetIntrinsic(VCMPGT, ElementKind);
2238         }
2239         break;
2240       case BO_GE:
2241         if (ElementKind == BuiltinType::Float) {
2242           CR6 = CR6_LT;
2243           ID = llvm::Intrinsic::ppc_altivec_vcmpgefp_p;
2244         }
2245         else {
2246           CR6 = CR6_EQ;
2247           ID = GetIntrinsic(VCMPGT, ElementKind);
2248           std::swap(FirstVecArg, SecondVecArg);
2249         }
2250         break;
2251       }
2252 
2253       Value *CR6Param = Builder.getInt32(CR6);
2254       llvm::Function *F = CGF.CGM.getIntrinsic(ID);
2255       Result = Builder.CreateCall3(F, CR6Param, FirstVecArg, SecondVecArg, "");
2256       return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType());
2257     }
2258 
2259     if (LHS->getType()->isFPOrFPVectorTy()) {
2260       Result = Builder.CreateFCmp((llvm::CmpInst::Predicate)FCmpOpc,
2261                                   LHS, RHS, "cmp");
2262     } else if (LHSTy->hasSignedIntegerRepresentation()) {
2263       Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)SICmpOpc,
2264                                   LHS, RHS, "cmp");
2265     } else {
2266       // Unsigned integers and pointers.
2267       Result = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
2268                                   LHS, RHS, "cmp");
2269     }
2270 
2271     // If this is a vector comparison, sign extend the result to the appropriate
2272     // vector integer type and return it (don't convert to bool).
2273     if (LHSTy->isVectorType())
2274       return Builder.CreateSExt(Result, ConvertType(E->getType()), "sext");
2275 
2276   } else {
2277     // Complex Comparison: can only be an equality comparison.
2278     CodeGenFunction::ComplexPairTy LHS = CGF.EmitComplexExpr(E->getLHS());
2279     CodeGenFunction::ComplexPairTy RHS = CGF.EmitComplexExpr(E->getRHS());
2280 
2281     QualType CETy = LHSTy->getAs<ComplexType>()->getElementType();
2282 
2283     Value *ResultR, *ResultI;
2284     if (CETy->isRealFloatingType()) {
2285       ResultR = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc,
2286                                    LHS.first, RHS.first, "cmp.r");
2287       ResultI = Builder.CreateFCmp((llvm::FCmpInst::Predicate)FCmpOpc,
2288                                    LHS.second, RHS.second, "cmp.i");
2289     } else {
2290       // Complex comparisons can only be equality comparisons.  As such, signed
2291       // and unsigned opcodes are the same.
2292       ResultR = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
2293                                    LHS.first, RHS.first, "cmp.r");
2294       ResultI = Builder.CreateICmp((llvm::ICmpInst::Predicate)UICmpOpc,
2295                                    LHS.second, RHS.second, "cmp.i");
2296     }
2297 
2298     if (E->getOpcode() == BO_EQ) {
2299       Result = Builder.CreateAnd(ResultR, ResultI, "and.ri");
2300     } else {
2301       assert(E->getOpcode() == BO_NE &&
2302              "Complex comparison other than == or != ?");
2303       Result = Builder.CreateOr(ResultR, ResultI, "or.ri");
2304     }
2305   }
2306 
2307   return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType());
2308 }
2309 
VisitBinAssign(const BinaryOperator * E)2310 Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) {
2311   bool Ignore = TestAndClearIgnoreResultAssign();
2312 
2313   Value *RHS;
2314   LValue LHS;
2315 
2316   switch (E->getLHS()->getType().getObjCLifetime()) {
2317   case Qualifiers::OCL_Strong:
2318     llvm::tie(LHS, RHS) = CGF.EmitARCStoreStrong(E, Ignore);
2319     break;
2320 
2321   case Qualifiers::OCL_Autoreleasing:
2322     llvm::tie(LHS,RHS) = CGF.EmitARCStoreAutoreleasing(E);
2323     break;
2324 
2325   case Qualifiers::OCL_Weak:
2326     RHS = Visit(E->getRHS());
2327     LHS = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
2328     RHS = CGF.EmitARCStoreWeak(LHS.getAddress(), RHS, Ignore);
2329     break;
2330 
2331   // No reason to do any of these differently.
2332   case Qualifiers::OCL_None:
2333   case Qualifiers::OCL_ExplicitNone:
2334     // __block variables need to have the rhs evaluated first, plus
2335     // this should improve codegen just a little.
2336     RHS = Visit(E->getRHS());
2337     LHS = EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
2338 
2339     // Store the value into the LHS.  Bit-fields are handled specially
2340     // because the result is altered by the store, i.e., [C99 6.5.16p1]
2341     // 'An assignment expression has the value of the left operand after
2342     // the assignment...'.
2343     if (LHS.isBitField())
2344       CGF.EmitStoreThroughBitfieldLValue(RValue::get(RHS), LHS, &RHS);
2345     else
2346       CGF.EmitStoreThroughLValue(RValue::get(RHS), LHS);
2347   }
2348 
2349   // If the result is clearly ignored, return now.
2350   if (Ignore)
2351     return 0;
2352 
2353   // The result of an assignment in C is the assigned r-value.
2354   if (!CGF.getContext().getLangOpts().CPlusPlus)
2355     return RHS;
2356 
2357   // If the lvalue is non-volatile, return the computed value of the assignment.
2358   if (!LHS.isVolatileQualified())
2359     return RHS;
2360 
2361   // Otherwise, reload the value.
2362   return EmitLoadOfLValue(LHS);
2363 }
2364 
VisitBinLAnd(const BinaryOperator * E)2365 Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) {
2366 
2367   // Perform vector logical and on comparisons with zero vectors.
2368   if (E->getType()->isVectorType()) {
2369     Value *LHS = Visit(E->getLHS());
2370     Value *RHS = Visit(E->getRHS());
2371     Value *Zero = llvm::ConstantAggregateZero::get(LHS->getType());
2372     LHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, LHS, Zero, "cmp");
2373     RHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, RHS, Zero, "cmp");
2374     Value *And = Builder.CreateAnd(LHS, RHS);
2375     return Builder.CreateSExt(And, Zero->getType(), "sext");
2376   }
2377 
2378   llvm::Type *ResTy = ConvertType(E->getType());
2379 
2380   // If we have 0 && RHS, see if we can elide RHS, if so, just return 0.
2381   // If we have 1 && X, just emit X without inserting the control flow.
2382   bool LHSCondVal;
2383   if (CGF.ConstantFoldsToSimpleInteger(E->getLHS(), LHSCondVal)) {
2384     if (LHSCondVal) { // If we have 1 && X, just emit X.
2385       Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
2386       // ZExt result to int or bool.
2387       return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "land.ext");
2388     }
2389 
2390     // 0 && RHS: If it is safe, just elide the RHS, and return 0/false.
2391     if (!CGF.ContainsLabel(E->getRHS()))
2392       return llvm::Constant::getNullValue(ResTy);
2393   }
2394 
2395   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("land.end");
2396   llvm::BasicBlock *RHSBlock  = CGF.createBasicBlock("land.rhs");
2397 
2398   CodeGenFunction::ConditionalEvaluation eval(CGF);
2399 
2400   // Branch on the LHS first.  If it is false, go to the failure (cont) block.
2401   CGF.EmitBranchOnBoolExpr(E->getLHS(), RHSBlock, ContBlock);
2402 
2403   // Any edges into the ContBlock are now from an (indeterminate number of)
2404   // edges from this first condition.  All of these values will be false.  Start
2405   // setting up the PHI node in the Cont Block for this.
2406   llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext), 2,
2407                                             "", ContBlock);
2408   for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
2409        PI != PE; ++PI)
2410     PN->addIncoming(llvm::ConstantInt::getFalse(VMContext), *PI);
2411 
2412   eval.begin(CGF);
2413   CGF.EmitBlock(RHSBlock);
2414   Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
2415   eval.end(CGF);
2416 
2417   // Reaquire the RHS block, as there may be subblocks inserted.
2418   RHSBlock = Builder.GetInsertBlock();
2419 
2420   // Emit an unconditional branch from this block to ContBlock.  Insert an entry
2421   // into the phi node for the edge with the value of RHSCond.
2422   if (CGF.getDebugInfo())
2423     // There is no need to emit line number for unconditional branch.
2424     Builder.SetCurrentDebugLocation(llvm::DebugLoc());
2425   CGF.EmitBlock(ContBlock);
2426   PN->addIncoming(RHSCond, RHSBlock);
2427 
2428   // ZExt result to int.
2429   return Builder.CreateZExtOrBitCast(PN, ResTy, "land.ext");
2430 }
2431 
VisitBinLOr(const BinaryOperator * E)2432 Value *ScalarExprEmitter::VisitBinLOr(const BinaryOperator *E) {
2433 
2434   // Perform vector logical or on comparisons with zero vectors.
2435   if (E->getType()->isVectorType()) {
2436     Value *LHS = Visit(E->getLHS());
2437     Value *RHS = Visit(E->getRHS());
2438     Value *Zero = llvm::ConstantAggregateZero::get(LHS->getType());
2439     LHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, LHS, Zero, "cmp");
2440     RHS = Builder.CreateICmp(llvm::CmpInst::ICMP_NE, RHS, Zero, "cmp");
2441     Value *Or = Builder.CreateOr(LHS, RHS);
2442     return Builder.CreateSExt(Or, Zero->getType(), "sext");
2443   }
2444 
2445   llvm::Type *ResTy = ConvertType(E->getType());
2446 
2447   // If we have 1 || RHS, see if we can elide RHS, if so, just return 1.
2448   // If we have 0 || X, just emit X without inserting the control flow.
2449   bool LHSCondVal;
2450   if (CGF.ConstantFoldsToSimpleInteger(E->getLHS(), LHSCondVal)) {
2451     if (!LHSCondVal) { // If we have 0 || X, just emit X.
2452       Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
2453       // ZExt result to int or bool.
2454       return Builder.CreateZExtOrBitCast(RHSCond, ResTy, "lor.ext");
2455     }
2456 
2457     // 1 || RHS: If it is safe, just elide the RHS, and return 1/true.
2458     if (!CGF.ContainsLabel(E->getRHS()))
2459       return llvm::ConstantInt::get(ResTy, 1);
2460   }
2461 
2462   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("lor.end");
2463   llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("lor.rhs");
2464 
2465   CodeGenFunction::ConditionalEvaluation eval(CGF);
2466 
2467   // Branch on the LHS first.  If it is true, go to the success (cont) block.
2468   CGF.EmitBranchOnBoolExpr(E->getLHS(), ContBlock, RHSBlock);
2469 
2470   // Any edges into the ContBlock are now from an (indeterminate number of)
2471   // edges from this first condition.  All of these values will be true.  Start
2472   // setting up the PHI node in the Cont Block for this.
2473   llvm::PHINode *PN = llvm::PHINode::Create(llvm::Type::getInt1Ty(VMContext), 2,
2474                                             "", ContBlock);
2475   for (llvm::pred_iterator PI = pred_begin(ContBlock), PE = pred_end(ContBlock);
2476        PI != PE; ++PI)
2477     PN->addIncoming(llvm::ConstantInt::getTrue(VMContext), *PI);
2478 
2479   eval.begin(CGF);
2480 
2481   // Emit the RHS condition as a bool value.
2482   CGF.EmitBlock(RHSBlock);
2483   Value *RHSCond = CGF.EvaluateExprAsBool(E->getRHS());
2484 
2485   eval.end(CGF);
2486 
2487   // Reaquire the RHS block, as there may be subblocks inserted.
2488   RHSBlock = Builder.GetInsertBlock();
2489 
2490   // Emit an unconditional branch from this block to ContBlock.  Insert an entry
2491   // into the phi node for the edge with the value of RHSCond.
2492   CGF.EmitBlock(ContBlock);
2493   PN->addIncoming(RHSCond, RHSBlock);
2494 
2495   // ZExt result to int.
2496   return Builder.CreateZExtOrBitCast(PN, ResTy, "lor.ext");
2497 }
2498 
VisitBinComma(const BinaryOperator * E)2499 Value *ScalarExprEmitter::VisitBinComma(const BinaryOperator *E) {
2500   CGF.EmitIgnoredExpr(E->getLHS());
2501   CGF.EnsureInsertPoint();
2502   return Visit(E->getRHS());
2503 }
2504 
2505 //===----------------------------------------------------------------------===//
2506 //                             Other Operators
2507 //===----------------------------------------------------------------------===//
2508 
2509 /// isCheapEnoughToEvaluateUnconditionally - Return true if the specified
2510 /// expression is cheap enough and side-effect-free enough to evaluate
2511 /// unconditionally instead of conditionally.  This is used to convert control
2512 /// flow into selects in some cases.
isCheapEnoughToEvaluateUnconditionally(const Expr * E,CodeGenFunction & CGF)2513 static bool isCheapEnoughToEvaluateUnconditionally(const Expr *E,
2514                                                    CodeGenFunction &CGF) {
2515   E = E->IgnoreParens();
2516 
2517   // Anything that is an integer or floating point constant is fine.
2518   if (E->isConstantInitializer(CGF.getContext(), false))
2519     return true;
2520 
2521   // Non-volatile automatic variables too, to get "cond ? X : Y" where
2522   // X and Y are local variables.
2523   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
2524     if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl()))
2525       if (VD->hasLocalStorage() && !(CGF.getContext()
2526                                      .getCanonicalType(VD->getType())
2527                                      .isVolatileQualified()))
2528         return true;
2529 
2530   return false;
2531 }
2532 
2533 
2534 Value *ScalarExprEmitter::
VisitAbstractConditionalOperator(const AbstractConditionalOperator * E)2535 VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) {
2536   TestAndClearIgnoreResultAssign();
2537 
2538   // Bind the common expression if necessary.
2539   CodeGenFunction::OpaqueValueMapping binding(CGF, E);
2540 
2541   Expr *condExpr = E->getCond();
2542   Expr *lhsExpr = E->getTrueExpr();
2543   Expr *rhsExpr = E->getFalseExpr();
2544 
2545   // If the condition constant folds and can be elided, try to avoid emitting
2546   // the condition and the dead arm.
2547   bool CondExprBool;
2548   if (CGF.ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
2549     Expr *live = lhsExpr, *dead = rhsExpr;
2550     if (!CondExprBool) std::swap(live, dead);
2551 
2552     // If the dead side doesn't have labels we need, just emit the Live part.
2553     if (!CGF.ContainsLabel(dead)) {
2554       Value *Result = Visit(live);
2555 
2556       // If the live part is a throw expression, it acts like it has a void
2557       // type, so evaluating it returns a null Value*.  However, a conditional
2558       // with non-void type must return a non-null Value*.
2559       if (!Result && !E->getType()->isVoidType())
2560         Result = llvm::UndefValue::get(CGF.ConvertType(E->getType()));
2561 
2562       return Result;
2563     }
2564   }
2565 
2566   // OpenCL: If the condition is a vector, we can treat this condition like
2567   // the select function.
2568   if (CGF.getContext().getLangOpts().OpenCL
2569       && condExpr->getType()->isVectorType()) {
2570     llvm::Value *CondV = CGF.EmitScalarExpr(condExpr);
2571     llvm::Value *LHS = Visit(lhsExpr);
2572     llvm::Value *RHS = Visit(rhsExpr);
2573 
2574     llvm::Type *condType = ConvertType(condExpr->getType());
2575     llvm::VectorType *vecTy = cast<llvm::VectorType>(condType);
2576 
2577     unsigned numElem = vecTy->getNumElements();
2578     llvm::Type *elemType = vecTy->getElementType();
2579 
2580     llvm::Value *zeroVec = llvm::Constant::getNullValue(vecTy);
2581     llvm::Value *TestMSB = Builder.CreateICmpSLT(CondV, zeroVec);
2582     llvm::Value *tmp = Builder.CreateSExt(TestMSB,
2583                                           llvm::VectorType::get(elemType,
2584                                                                 numElem),
2585                                           "sext");
2586     llvm::Value *tmp2 = Builder.CreateNot(tmp);
2587 
2588     // Cast float to int to perform ANDs if necessary.
2589     llvm::Value *RHSTmp = RHS;
2590     llvm::Value *LHSTmp = LHS;
2591     bool wasCast = false;
2592     llvm::VectorType *rhsVTy = cast<llvm::VectorType>(RHS->getType());
2593     if (rhsVTy->getElementType()->isFloatingPointTy()) {
2594       RHSTmp = Builder.CreateBitCast(RHS, tmp2->getType());
2595       LHSTmp = Builder.CreateBitCast(LHS, tmp->getType());
2596       wasCast = true;
2597     }
2598 
2599     llvm::Value *tmp3 = Builder.CreateAnd(RHSTmp, tmp2);
2600     llvm::Value *tmp4 = Builder.CreateAnd(LHSTmp, tmp);
2601     llvm::Value *tmp5 = Builder.CreateOr(tmp3, tmp4, "cond");
2602     if (wasCast)
2603       tmp5 = Builder.CreateBitCast(tmp5, RHS->getType());
2604 
2605     return tmp5;
2606   }
2607 
2608   // If this is a really simple expression (like x ? 4 : 5), emit this as a
2609   // select instead of as control flow.  We can only do this if it is cheap and
2610   // safe to evaluate the LHS and RHS unconditionally.
2611   if (isCheapEnoughToEvaluateUnconditionally(lhsExpr, CGF) &&
2612       isCheapEnoughToEvaluateUnconditionally(rhsExpr, CGF)) {
2613     llvm::Value *CondV = CGF.EvaluateExprAsBool(condExpr);
2614     llvm::Value *LHS = Visit(lhsExpr);
2615     llvm::Value *RHS = Visit(rhsExpr);
2616     if (!LHS) {
2617       // If the conditional has void type, make sure we return a null Value*.
2618       assert(!RHS && "LHS and RHS types must match");
2619       return 0;
2620     }
2621     return Builder.CreateSelect(CondV, LHS, RHS, "cond");
2622   }
2623 
2624   llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true");
2625   llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false");
2626   llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end");
2627 
2628   CodeGenFunction::ConditionalEvaluation eval(CGF);
2629   CGF.EmitBranchOnBoolExpr(condExpr, LHSBlock, RHSBlock);
2630 
2631   CGF.EmitBlock(LHSBlock);
2632   eval.begin(CGF);
2633   Value *LHS = Visit(lhsExpr);
2634   eval.end(CGF);
2635 
2636   LHSBlock = Builder.GetInsertBlock();
2637   Builder.CreateBr(ContBlock);
2638 
2639   CGF.EmitBlock(RHSBlock);
2640   eval.begin(CGF);
2641   Value *RHS = Visit(rhsExpr);
2642   eval.end(CGF);
2643 
2644   RHSBlock = Builder.GetInsertBlock();
2645   CGF.EmitBlock(ContBlock);
2646 
2647   // If the LHS or RHS is a throw expression, it will be legitimately null.
2648   if (!LHS)
2649     return RHS;
2650   if (!RHS)
2651     return LHS;
2652 
2653   // Create a PHI node for the real part.
2654   llvm::PHINode *PN = Builder.CreatePHI(LHS->getType(), 2, "cond");
2655   PN->addIncoming(LHS, LHSBlock);
2656   PN->addIncoming(RHS, RHSBlock);
2657   return PN;
2658 }
2659 
VisitChooseExpr(ChooseExpr * E)2660 Value *ScalarExprEmitter::VisitChooseExpr(ChooseExpr *E) {
2661   return Visit(E->getChosenSubExpr(CGF.getContext()));
2662 }
2663 
VisitVAArgExpr(VAArgExpr * VE)2664 Value *ScalarExprEmitter::VisitVAArgExpr(VAArgExpr *VE) {
2665   llvm::Value *ArgValue = CGF.EmitVAListRef(VE->getSubExpr());
2666   llvm::Value *ArgPtr = CGF.EmitVAArg(ArgValue, VE->getType());
2667 
2668   // If EmitVAArg fails, we fall back to the LLVM instruction.
2669   if (!ArgPtr)
2670     return Builder.CreateVAArg(ArgValue, ConvertType(VE->getType()));
2671 
2672   // FIXME Volatility.
2673   return Builder.CreateLoad(ArgPtr);
2674 }
2675 
VisitBlockExpr(const BlockExpr * block)2676 Value *ScalarExprEmitter::VisitBlockExpr(const BlockExpr *block) {
2677   return CGF.EmitBlockLiteral(block);
2678 }
2679 
VisitAsTypeExpr(AsTypeExpr * E)2680 Value *ScalarExprEmitter::VisitAsTypeExpr(AsTypeExpr *E) {
2681   Value *Src  = CGF.EmitScalarExpr(E->getSrcExpr());
2682   llvm::Type *DstTy = ConvertType(E->getType());
2683 
2684   // Going from vec4->vec3 or vec3->vec4 is a special case and requires
2685   // a shuffle vector instead of a bitcast.
2686   llvm::Type *SrcTy = Src->getType();
2687   if (isa<llvm::VectorType>(DstTy) && isa<llvm::VectorType>(SrcTy)) {
2688     unsigned numElementsDst = cast<llvm::VectorType>(DstTy)->getNumElements();
2689     unsigned numElementsSrc = cast<llvm::VectorType>(SrcTy)->getNumElements();
2690     if ((numElementsDst == 3 && numElementsSrc == 4)
2691         || (numElementsDst == 4 && numElementsSrc == 3)) {
2692 
2693 
2694       // In the case of going from int4->float3, a bitcast is needed before
2695       // doing a shuffle.
2696       llvm::Type *srcElemTy =
2697       cast<llvm::VectorType>(SrcTy)->getElementType();
2698       llvm::Type *dstElemTy =
2699       cast<llvm::VectorType>(DstTy)->getElementType();
2700 
2701       if ((srcElemTy->isIntegerTy() && dstElemTy->isFloatTy())
2702           || (srcElemTy->isFloatTy() && dstElemTy->isIntegerTy())) {
2703         // Create a float type of the same size as the source or destination.
2704         llvm::VectorType *newSrcTy = llvm::VectorType::get(dstElemTy,
2705                                                                  numElementsSrc);
2706 
2707         Src = Builder.CreateBitCast(Src, newSrcTy, "astypeCast");
2708       }
2709 
2710       llvm::Value *UnV = llvm::UndefValue::get(Src->getType());
2711 
2712       SmallVector<llvm::Constant*, 3> Args;
2713       Args.push_back(Builder.getInt32(0));
2714       Args.push_back(Builder.getInt32(1));
2715       Args.push_back(Builder.getInt32(2));
2716 
2717       if (numElementsDst == 4)
2718         Args.push_back(llvm::UndefValue::get(CGF.Int32Ty));
2719 
2720       llvm::Constant *Mask = llvm::ConstantVector::get(Args);
2721 
2722       return Builder.CreateShuffleVector(Src, UnV, Mask, "astype");
2723     }
2724   }
2725 
2726   return Builder.CreateBitCast(Src, DstTy, "astype");
2727 }
2728 
VisitAtomicExpr(AtomicExpr * E)2729 Value *ScalarExprEmitter::VisitAtomicExpr(AtomicExpr *E) {
2730   return CGF.EmitAtomicExpr(E).getScalarVal();
2731 }
2732 
2733 //===----------------------------------------------------------------------===//
2734 //                         Entry Point into this File
2735 //===----------------------------------------------------------------------===//
2736 
2737 /// EmitScalarExpr - Emit the computation of the specified expression of scalar
2738 /// type, ignoring the result.
EmitScalarExpr(const Expr * E,bool IgnoreResultAssign)2739 Value *CodeGenFunction::EmitScalarExpr(const Expr *E, bool IgnoreResultAssign) {
2740   assert(E && !hasAggregateLLVMType(E->getType()) &&
2741          "Invalid scalar expression to emit");
2742 
2743   if (isa<CXXDefaultArgExpr>(E))
2744     disableDebugInfo();
2745   Value *V = ScalarExprEmitter(*this, IgnoreResultAssign)
2746     .Visit(const_cast<Expr*>(E));
2747   if (isa<CXXDefaultArgExpr>(E))
2748     enableDebugInfo();
2749   return V;
2750 }
2751 
2752 /// EmitScalarConversion - Emit a conversion from the specified type to the
2753 /// specified destination type, both of which are LLVM scalar types.
EmitScalarConversion(Value * Src,QualType SrcTy,QualType DstTy)2754 Value *CodeGenFunction::EmitScalarConversion(Value *Src, QualType SrcTy,
2755                                              QualType DstTy) {
2756   assert(!hasAggregateLLVMType(SrcTy) && !hasAggregateLLVMType(DstTy) &&
2757          "Invalid scalar expression to emit");
2758   return ScalarExprEmitter(*this).EmitScalarConversion(Src, SrcTy, DstTy);
2759 }
2760 
2761 /// EmitComplexToScalarConversion - Emit a conversion from the specified complex
2762 /// type to the specified destination type, where the destination type is an
2763 /// LLVM scalar type.
EmitComplexToScalarConversion(ComplexPairTy Src,QualType SrcTy,QualType DstTy)2764 Value *CodeGenFunction::EmitComplexToScalarConversion(ComplexPairTy Src,
2765                                                       QualType SrcTy,
2766                                                       QualType DstTy) {
2767   assert(SrcTy->isAnyComplexType() && !hasAggregateLLVMType(DstTy) &&
2768          "Invalid complex -> scalar conversion");
2769   return ScalarExprEmitter(*this).EmitComplexToScalarConversion(Src, SrcTy,
2770                                                                 DstTy);
2771 }
2772 
2773 
2774 llvm::Value *CodeGenFunction::
EmitScalarPrePostIncDec(const UnaryOperator * E,LValue LV,bool isInc,bool isPre)2775 EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
2776                         bool isInc, bool isPre) {
2777   return ScalarExprEmitter(*this).EmitScalarPrePostIncDec(E, LV, isInc, isPre);
2778 }
2779 
EmitObjCIsaExpr(const ObjCIsaExpr * E)2780 LValue CodeGenFunction::EmitObjCIsaExpr(const ObjCIsaExpr *E) {
2781   llvm::Value *V;
2782   // object->isa or (*object).isa
2783   // Generate code as for: *(Class*)object
2784   // build Class* type
2785   llvm::Type *ClassPtrTy = ConvertType(E->getType());
2786 
2787   Expr *BaseExpr = E->getBase();
2788   if (BaseExpr->isRValue()) {
2789     V = CreateMemTemp(E->getType(), "resval");
2790     llvm::Value *Src = EmitScalarExpr(BaseExpr);
2791     Builder.CreateStore(Src, V);
2792     V = ScalarExprEmitter(*this).EmitLoadOfLValue(
2793       MakeNaturalAlignAddrLValue(V, E->getType()));
2794   } else {
2795     if (E->isArrow())
2796       V = ScalarExprEmitter(*this).EmitLoadOfLValue(BaseExpr);
2797     else
2798       V = EmitLValue(BaseExpr).getAddress();
2799   }
2800 
2801   // build Class* type
2802   ClassPtrTy = ClassPtrTy->getPointerTo();
2803   V = Builder.CreateBitCast(V, ClassPtrTy);
2804   return MakeNaturalAlignAddrLValue(V, E->getType());
2805 }
2806 
2807 
EmitCompoundAssignmentLValue(const CompoundAssignOperator * E)2808 LValue CodeGenFunction::EmitCompoundAssignmentLValue(
2809                                             const CompoundAssignOperator *E) {
2810   ScalarExprEmitter Scalar(*this);
2811   Value *Result = 0;
2812   switch (E->getOpcode()) {
2813 #define COMPOUND_OP(Op)                                                       \
2814     case BO_##Op##Assign:                                                     \
2815       return Scalar.EmitCompoundAssignLValue(E, &ScalarExprEmitter::Emit##Op, \
2816                                              Result)
2817   COMPOUND_OP(Mul);
2818   COMPOUND_OP(Div);
2819   COMPOUND_OP(Rem);
2820   COMPOUND_OP(Add);
2821   COMPOUND_OP(Sub);
2822   COMPOUND_OP(Shl);
2823   COMPOUND_OP(Shr);
2824   COMPOUND_OP(And);
2825   COMPOUND_OP(Xor);
2826   COMPOUND_OP(Or);
2827 #undef COMPOUND_OP
2828 
2829   case BO_PtrMemD:
2830   case BO_PtrMemI:
2831   case BO_Mul:
2832   case BO_Div:
2833   case BO_Rem:
2834   case BO_Add:
2835   case BO_Sub:
2836   case BO_Shl:
2837   case BO_Shr:
2838   case BO_LT:
2839   case BO_GT:
2840   case BO_LE:
2841   case BO_GE:
2842   case BO_EQ:
2843   case BO_NE:
2844   case BO_And:
2845   case BO_Xor:
2846   case BO_Or:
2847   case BO_LAnd:
2848   case BO_LOr:
2849   case BO_Assign:
2850   case BO_Comma:
2851     llvm_unreachable("Not valid compound assignment operators");
2852   }
2853 
2854   llvm_unreachable("Unhandled compound assignment operator");
2855 }
2856