1 #include "AliasAnalysisSummary.h"
2 #include "llvm/IR/Argument.h"
3 #include "llvm/IR/Type.h"
4 #include "llvm/Support/Compiler.h"
5
6 namespace llvm {
7 namespace cflaa {
8
9 namespace {
10 LLVM_CONSTEXPR unsigned AttrEscapedIndex = 0;
11 LLVM_CONSTEXPR unsigned AttrUnknownIndex = 1;
12 LLVM_CONSTEXPR unsigned AttrGlobalIndex = 2;
13 LLVM_CONSTEXPR unsigned AttrCallerIndex = 3;
14 LLVM_CONSTEXPR unsigned AttrFirstArgIndex = 4;
15 LLVM_CONSTEXPR unsigned AttrLastArgIndex = NumAliasAttrs;
16 LLVM_CONSTEXPR unsigned AttrMaxNumArgs = AttrLastArgIndex - AttrFirstArgIndex;
17
18 // NOTE: These aren't AliasAttrs because bitsets don't have a constexpr
19 // ctor for some versions of MSVC that we support. We could maybe refactor,
20 // but...
21 using AliasAttr = unsigned;
22 LLVM_CONSTEXPR AliasAttr AttrNone = 0;
23 LLVM_CONSTEXPR AliasAttr AttrEscaped = 1 << AttrEscapedIndex;
24 LLVM_CONSTEXPR AliasAttr AttrUnknown = 1 << AttrUnknownIndex;
25 LLVM_CONSTEXPR AliasAttr AttrGlobal = 1 << AttrGlobalIndex;
26 LLVM_CONSTEXPR AliasAttr AttrCaller = 1 << AttrCallerIndex;
27 LLVM_CONSTEXPR AliasAttr ExternalAttrMask =
28 AttrEscaped | AttrUnknown | AttrGlobal;
29 }
30
getAttrNone()31 AliasAttrs getAttrNone() { return AttrNone; }
32
getAttrUnknown()33 AliasAttrs getAttrUnknown() { return AttrUnknown; }
hasUnknownAttr(AliasAttrs Attr)34 bool hasUnknownAttr(AliasAttrs Attr) { return Attr.test(AttrUnknownIndex); }
35
getAttrCaller()36 AliasAttrs getAttrCaller() { return AttrCaller; }
hasCallerAttr(AliasAttrs Attr)37 bool hasCallerAttr(AliasAttrs Attr) { return Attr.test(AttrCaller); }
hasUnknownOrCallerAttr(AliasAttrs Attr)38 bool hasUnknownOrCallerAttr(AliasAttrs Attr) {
39 return Attr.test(AttrUnknownIndex) || Attr.test(AttrCallerIndex);
40 }
41
getAttrEscaped()42 AliasAttrs getAttrEscaped() { return AttrEscaped; }
hasEscapedAttr(AliasAttrs Attr)43 bool hasEscapedAttr(AliasAttrs Attr) { return Attr.test(AttrEscapedIndex); }
44
argNumberToAttr(unsigned ArgNum)45 static AliasAttr argNumberToAttr(unsigned ArgNum) {
46 if (ArgNum >= AttrMaxNumArgs)
47 return AttrUnknown;
48 // N.B. MSVC complains if we use `1U` here, since AliasAttr' ctor takes
49 // an unsigned long long.
50 return AliasAttr(1ULL << (ArgNum + AttrFirstArgIndex));
51 }
52
getGlobalOrArgAttrFromValue(const Value & Val)53 AliasAttrs getGlobalOrArgAttrFromValue(const Value &Val) {
54 if (isa<GlobalValue>(Val))
55 return AttrGlobal;
56
57 if (auto *Arg = dyn_cast<Argument>(&Val))
58 // Only pointer arguments should have the argument attribute,
59 // because things can't escape through scalars without us seeing a
60 // cast, and thus, interaction with them doesn't matter.
61 if (!Arg->hasNoAliasAttr() && Arg->getType()->isPointerTy())
62 return argNumberToAttr(Arg->getArgNo());
63 return AttrNone;
64 }
65
isGlobalOrArgAttr(AliasAttrs Attr)66 bool isGlobalOrArgAttr(AliasAttrs Attr) {
67 return Attr.reset(AttrEscapedIndex)
68 .reset(AttrUnknownIndex)
69 .reset(AttrCallerIndex)
70 .any();
71 }
72
getExternallyVisibleAttrs(AliasAttrs Attr)73 AliasAttrs getExternallyVisibleAttrs(AliasAttrs Attr) {
74 return Attr & AliasAttrs(ExternalAttrMask);
75 }
76
instantiateInterfaceValue(InterfaceValue IValue,CallSite CS)77 Optional<InstantiatedValue> instantiateInterfaceValue(InterfaceValue IValue,
78 CallSite CS) {
79 auto Index = IValue.Index;
80 auto Value = (Index == 0) ? CS.getInstruction() : CS.getArgument(Index - 1);
81 if (Value->getType()->isPointerTy())
82 return InstantiatedValue{Value, IValue.DerefLevel};
83 return None;
84 }
85
86 Optional<InstantiatedRelation>
instantiateExternalRelation(ExternalRelation ERelation,CallSite CS)87 instantiateExternalRelation(ExternalRelation ERelation, CallSite CS) {
88 auto From = instantiateInterfaceValue(ERelation.From, CS);
89 if (!From)
90 return None;
91 auto To = instantiateInterfaceValue(ERelation.To, CS);
92 if (!To)
93 return None;
94 return InstantiatedRelation{*From, *To};
95 }
96
instantiateExternalAttribute(ExternalAttribute EAttr,CallSite CS)97 Optional<InstantiatedAttr> instantiateExternalAttribute(ExternalAttribute EAttr,
98 CallSite CS) {
99 auto Value = instantiateInterfaceValue(EAttr.IValue, CS);
100 if (!Value)
101 return None;
102 return InstantiatedAttr{*Value, EAttr.Attr};
103 }
104 }
105 }
106