AArch64MCExpr.cpp revision 360784 
1//===-- AArch64MCExpr.cpp - AArch64 specific MC expression classes --------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains the implementation of the assembly expression modifiers
10// accepted by the AArch64 architecture (e.g. ":lo12:", ":gottprel_g1:", ...).
11//
12//===----------------------------------------------------------------------===//
13
14#include "AArch64MCExpr.h"
15#include "llvm/BinaryFormat/ELF.h"
16#include "llvm/MC/MCContext.h"
17#include "llvm/MC/MCStreamer.h"
18#include "llvm/MC/MCSymbolELF.h"
19#include "llvm/MC/MCValue.h"
20#include "llvm/Support/ErrorHandling.h"
21
22using namespace llvm;
23
24#define DEBUG_TYPE "aarch64symbolrefexpr"
25
26const AArch64MCExpr *AArch64MCExpr::create(const MCExpr *Expr, VariantKind Kind,
27                                       MCContext &Ctx) {
28  return new (Ctx) AArch64MCExpr(Expr, Kind);
29}
30
31StringRef AArch64MCExpr::getVariantKindName() const {
32  switch (static_cast<uint32_t>(getKind())) {
33  case VK_CALL:                return "";
34  case VK_LO12:                return ":lo12:";
35  case VK_ABS_G3:              return ":abs_g3:";
36  case VK_ABS_G2:              return ":abs_g2:";
37  case VK_ABS_G2_S:            return ":abs_g2_s:";
38  case VK_ABS_G2_NC:           return ":abs_g2_nc:";
39  case VK_ABS_G1:              return ":abs_g1:";
40  case VK_ABS_G1_S:            return ":abs_g1_s:";
41  case VK_ABS_G1_NC:           return ":abs_g1_nc:";
42  case VK_ABS_G0:              return ":abs_g0:";
43  case VK_ABS_G0_S:            return ":abs_g0_s:";
44  case VK_ABS_G0_NC:           return ":abs_g0_nc:";
45  case VK_PREL_G3:             return ":prel_g3:";
46  case VK_PREL_G2:             return ":prel_g2:";
47  case VK_PREL_G2_NC:          return ":prel_g2_nc:";
48  case VK_PREL_G1:             return ":prel_g1:";
49  case VK_PREL_G1_NC:          return ":prel_g1_nc:";
50  case VK_PREL_G0:             return ":prel_g0:";
51  case VK_PREL_G0_NC:          return ":prel_g0_nc:";
52  case VK_DTPREL_G2:           return ":dtprel_g2:";
53  case VK_DTPREL_G1:           return ":dtprel_g1:";
54  case VK_DTPREL_G1_NC:        return ":dtprel_g1_nc:";
55  case VK_DTPREL_G0:           return ":dtprel_g0:";
56  case VK_DTPREL_G0_NC:        return ":dtprel_g0_nc:";
57  case VK_DTPREL_HI12:         return ":dtprel_hi12:";
58  case VK_DTPREL_LO12:         return ":dtprel_lo12:";
59  case VK_DTPREL_LO12_NC:      return ":dtprel_lo12_nc:";
60  case VK_TPREL_G2:            return ":tprel_g2:";
61  case VK_TPREL_G1:            return ":tprel_g1:";
62  case VK_TPREL_G1_NC:         return ":tprel_g1_nc:";
63  case VK_TPREL_G0:            return ":tprel_g0:";
64  case VK_TPREL_G0_NC:         return ":tprel_g0_nc:";
65  case VK_TPREL_HI12:          return ":tprel_hi12:";
66  case VK_TPREL_LO12:          return ":tprel_lo12:";
67  case VK_TPREL_LO12_NC:       return ":tprel_lo12_nc:";
68  case VK_TLSDESC_LO12:        return ":tlsdesc_lo12:";
69  case VK_ABS_PAGE:            return "";
70  case VK_ABS_PAGE_NC:         return ":pg_hi21_nc:";
71  case VK_GOT:                 return ":got:";
72  case VK_GOT_PAGE:            return ":got:";
73  case VK_GOT_LO12:            return ":got_lo12:";
74  case VK_GOTTPREL:            return ":gottprel:";
75  case VK_GOTTPREL_PAGE:       return ":gottprel:";
76  case VK_GOTTPREL_LO12_NC:    return ":gottprel_lo12:";
77  case VK_GOTTPREL_G1:         return ":gottprel_g1:";
78  case VK_GOTTPREL_G0_NC:      return ":gottprel_g0_nc:";
79  case VK_TLSDESC:             return "";
80  case VK_TLSDESC_PAGE:        return ":tlsdesc:";
81  case VK_SECREL_LO12:         return ":secrel_lo12:";
82  case VK_SECREL_HI12:         return ":secrel_hi12:";
83  default:
84    llvm_unreachable("Invalid ELF symbol kind");
85  }
86}
87
88void AArch64MCExpr::printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const {
89  OS << getVariantKindName();
90  Expr->print(OS, MAI);
91}
92
93void AArch64MCExpr::visitUsedExpr(MCStreamer &Streamer) const {
94  Streamer.visitUsedExpr(*getSubExpr());
95}
96
97MCFragment *AArch64MCExpr::findAssociatedFragment() const {
98  llvm_unreachable("FIXME: what goes here?");
99}
100
101bool AArch64MCExpr::evaluateAsRelocatableImpl(MCValue &Res,
102                                              const MCAsmLayout *Layout,
103                                              const MCFixup *Fixup) const {
104  if (!getSubExpr()->evaluateAsRelocatable(Res, Layout, Fixup))
105    return false;
106
107  Res =
108      MCValue::get(Res.getSymA(), Res.getSymB(), Res.getConstant(), getKind());
109
110  return true;
111}
112
113static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm) {
114  switch (Expr->getKind()) {
115  case MCExpr::Target:
116    llvm_unreachable("Can't handle nested target expression");
117    break;
118  case MCExpr::Constant:
119    break;
120
121  case MCExpr::Binary: {
122    const MCBinaryExpr *BE = cast<MCBinaryExpr>(Expr);
123    fixELFSymbolsInTLSFixupsImpl(BE->getLHS(), Asm);
124    fixELFSymbolsInTLSFixupsImpl(BE->getRHS(), Asm);
125    break;
126  }
127
128  case MCExpr::SymbolRef: {
129    // We're known to be under a TLS fixup, so any symbol should be
130    // modified. There should be only one.
131    const MCSymbolRefExpr &SymRef = *cast<MCSymbolRefExpr>(Expr);
132    cast<MCSymbolELF>(SymRef.getSymbol()).setType(ELF::STT_TLS);
133    break;
134  }
135
136  case MCExpr::Unary:
137    fixELFSymbolsInTLSFixupsImpl(cast<MCUnaryExpr>(Expr)->getSubExpr(), Asm);
138    break;
139  }
140}
141
142void AArch64MCExpr::fixELFSymbolsInTLSFixups(MCAssembler &Asm) const {
143  switch (getSymbolLoc(Kind)) {
144  default:
145    return;
146  case VK_DTPREL:
147  case VK_GOTTPREL:
148  case VK_TPREL:
149  case VK_TLSDESC:
150    break;
151  }
152
153  fixELFSymbolsInTLSFixupsImpl(getSubExpr(), Asm);
154}
155