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1 //===-- AArch64MCExpr.cpp - AArch64 specific MC expression classes --------===//
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 file contains the implementation of the assembly expression modifiers
11 // accepted by the AArch64 architecture (e.g. ":lo12:", ":gottprel_g1:", ...).
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "AArch64MCExpr.h"
16 #include "llvm/MC/MCAssembler.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCStreamer.h"
19 #include "llvm/MC/MCSymbolELF.h"
20 #include "llvm/MC/MCValue.h"
21 #include "llvm/Object/ELF.h"
22 #include "llvm/Support/ErrorHandling.h"
23 
24 using namespace llvm;
25 
26 #define DEBUG_TYPE "aarch64symbolrefexpr"
27 
create(const MCExpr * Expr,VariantKind Kind,MCContext & Ctx)28 const AArch64MCExpr *AArch64MCExpr::create(const MCExpr *Expr, VariantKind Kind,
29                                        MCContext &Ctx) {
30   return new (Ctx) AArch64MCExpr(Expr, Kind);
31 }
32 
getVariantKindName() const33 StringRef AArch64MCExpr::getVariantKindName() const {
34   switch (static_cast<uint32_t>(getKind())) {
35   case VK_CALL:                return "";
36   case VK_LO12:                return ":lo12:";
37   case VK_ABS_G3:              return ":abs_g3:";
38   case VK_ABS_G2:              return ":abs_g2:";
39   case VK_ABS_G2_S:            return ":abs_g2_s:";
40   case VK_ABS_G2_NC:           return ":abs_g2_nc:";
41   case VK_ABS_G1:              return ":abs_g1:";
42   case VK_ABS_G1_S:            return ":abs_g1_s:";
43   case VK_ABS_G1_NC:           return ":abs_g1_nc:";
44   case VK_ABS_G0:              return ":abs_g0:";
45   case VK_ABS_G0_S:            return ":abs_g0_s:";
46   case VK_ABS_G0_NC:           return ":abs_g0_nc:";
47   case VK_DTPREL_G2:           return ":dtprel_g2:";
48   case VK_DTPREL_G1:           return ":dtprel_g1:";
49   case VK_DTPREL_G1_NC:        return ":dtprel_g1_nc:";
50   case VK_DTPREL_G0:           return ":dtprel_g0:";
51   case VK_DTPREL_G0_NC:        return ":dtprel_g0_nc:";
52   case VK_DTPREL_HI12:         return ":dtprel_hi12:";
53   case VK_DTPREL_LO12:         return ":dtprel_lo12:";
54   case VK_DTPREL_LO12_NC:      return ":dtprel_lo12_nc:";
55   case VK_TPREL_G2:            return ":tprel_g2:";
56   case VK_TPREL_G1:            return ":tprel_g1:";
57   case VK_TPREL_G1_NC:         return ":tprel_g1_nc:";
58   case VK_TPREL_G0:            return ":tprel_g0:";
59   case VK_TPREL_G0_NC:         return ":tprel_g0_nc:";
60   case VK_TPREL_HI12:          return ":tprel_hi12:";
61   case VK_TPREL_LO12:          return ":tprel_lo12:";
62   case VK_TPREL_LO12_NC:       return ":tprel_lo12_nc:";
63   case VK_TLSDESC_LO12:        return ":tlsdesc_lo12:";
64   case VK_ABS_PAGE:            return "";
65   case VK_GOT_PAGE:            return ":got:";
66   case VK_GOT_LO12:            return ":got_lo12:";
67   case VK_GOTTPREL_PAGE:       return ":gottprel:";
68   case VK_GOTTPREL_LO12_NC:    return ":gottprel_lo12:";
69   case VK_GOTTPREL_G1:         return ":gottprel_g1:";
70   case VK_GOTTPREL_G0_NC:      return ":gottprel_g0_nc:";
71   case VK_TLSDESC:             return "";
72   case VK_TLSDESC_PAGE:        return ":tlsdesc:";
73   default:
74     llvm_unreachable("Invalid ELF symbol kind");
75   }
76 }
77 
printImpl(raw_ostream & OS,const MCAsmInfo * MAI) const78 void AArch64MCExpr::printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const {
79   if (getKind() != VK_NONE)
80     OS << getVariantKindName();
81   Expr->print(OS, MAI);
82 }
83 
visitUsedExpr(MCStreamer & Streamer) const84 void AArch64MCExpr::visitUsedExpr(MCStreamer &Streamer) const {
85   Streamer.visitUsedExpr(*getSubExpr());
86 }
87 
findAssociatedFragment() const88 MCFragment *AArch64MCExpr::findAssociatedFragment() const {
89   llvm_unreachable("FIXME: what goes here?");
90 }
91 
evaluateAsRelocatableImpl(MCValue & Res,const MCAsmLayout * Layout,const MCFixup * Fixup) const92 bool AArch64MCExpr::evaluateAsRelocatableImpl(MCValue &Res,
93                                               const MCAsmLayout *Layout,
94                                               const MCFixup *Fixup) const {
95   if (!getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup))
96     return false;
97 
98   Res =
99       MCValue::get(Res.getSymA(), Res.getSymB(), Res.getConstant(), getKind());
100 
101   return true;
102 }
103 
fixELFSymbolsInTLSFixupsImpl(const MCExpr * Expr,MCAssembler & Asm)104 static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm) {
105   switch (Expr->getKind()) {
106   case MCExpr::Target:
107     llvm_unreachable("Can't handle nested target expression");
108     break;
109   case MCExpr::Constant:
110     break;
111 
112   case MCExpr::Binary: {
113     const MCBinaryExpr *BE = cast<MCBinaryExpr>(Expr);
114     fixELFSymbolsInTLSFixupsImpl(BE->getLHS(), Asm);
115     fixELFSymbolsInTLSFixupsImpl(BE->getRHS(), Asm);
116     break;
117   }
118 
119   case MCExpr::SymbolRef: {
120     // We're known to be under a TLS fixup, so any symbol should be
121     // modified. There should be only one.
122     const MCSymbolRefExpr &SymRef = *cast<MCSymbolRefExpr>(Expr);
123     cast<MCSymbolELF>(SymRef.getSymbol()).setType(ELF::STT_TLS);
124     break;
125   }
126 
127   case MCExpr::Unary:
128     fixELFSymbolsInTLSFixupsImpl(cast<MCUnaryExpr>(Expr)->getSubExpr(), Asm);
129     break;
130   }
131 }
132 
fixELFSymbolsInTLSFixups(MCAssembler & Asm) const133 void AArch64MCExpr::fixELFSymbolsInTLSFixups(MCAssembler &Asm) const {
134   switch (getSymbolLoc(Kind)) {
135   default:
136     return;
137   case VK_DTPREL:
138   case VK_GOTTPREL:
139   case VK_TPREL:
140   case VK_TLSDESC:
141     break;
142   }
143 
144   fixELFSymbolsInTLSFixupsImpl(getSubExpr(), Asm);
145 }
146