LLVM 20.0.0git
RISCVMCExpr.cpp
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1//===-- RISCVMCExpr.cpp - RISC-V 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 RISC-V architecture (e.g. ":lo12:", ":gottprel_g1:", ...).
11//
12//===----------------------------------------------------------------------===//
13
14#include "RISCVMCExpr.h"
16#include "RISCVFixupKinds.h"
18#include "llvm/MC/MCAssembler.h"
19#include "llvm/MC/MCContext.h"
20#include "llvm/MC/MCStreamer.h"
21#include "llvm/MC/MCSymbolELF.h"
22#include "llvm/MC/MCValue.h"
25
26using namespace llvm;
27
28#define DEBUG_TYPE "riscvmcexpr"
29
31 MCContext &Ctx) {
32 return new (Ctx) RISCVMCExpr(Expr, Kind);
33}
34
36 VariantKind Kind = getKind();
37 bool HasVariant = ((Kind != VK_RISCV_None) && (Kind != VK_RISCV_CALL) &&
38 (Kind != VK_RISCV_CALL_PLT));
39
40 if (HasVariant)
41 OS << '%' << getVariantKindName(getKind()) << '(';
42 Expr->print(OS, MAI);
43 if (HasVariant)
44 OS << ')';
45}
46
47const MCFixup *RISCVMCExpr::getPCRelHiFixup(const MCFragment **DFOut) const {
48 MCValue AUIPCLoc;
49 if (!getSubExpr()->evaluateAsRelocatable(AUIPCLoc, nullptr, nullptr))
50 return nullptr;
51
52 const MCSymbolRefExpr *AUIPCSRE = AUIPCLoc.getSymA();
53 if (!AUIPCSRE)
54 return nullptr;
55
56 const MCSymbol *AUIPCSymbol = &AUIPCSRE->getSymbol();
57 const auto *DF = dyn_cast_or_null<MCDataFragment>(AUIPCSymbol->getFragment());
58
59 if (!DF)
60 return nullptr;
61
62 uint64_t Offset = AUIPCSymbol->getOffset();
63 if (DF->getContents().size() == Offset) {
64 DF = dyn_cast_or_null<MCDataFragment>(DF->getNext());
65 if (!DF)
66 return nullptr;
67 Offset = 0;
68 }
69
70 for (const MCFixup &F : DF->getFixups()) {
71 if (F.getOffset() != Offset)
72 continue;
73
74 switch ((unsigned)F.getKind()) {
75 default:
76 continue;
82 if (DFOut)
83 *DFOut = DF;
84 return &F;
85 }
86 }
87
88 return nullptr;
89}
90
92 const MCAssembler *Asm,
93 const MCFixup *Fixup) const {
94 // Explicitly drop the layout and assembler to prevent any symbolic folding in
95 // the expression handling. This is required to preserve symbolic difference
96 // expressions to emit the paired relocations.
97 if (!getSubExpr()->evaluateAsRelocatable(Res, nullptr, nullptr))
98 return false;
99
100 Res =
101 MCValue::get(Res.getSymA(), Res.getSymB(), Res.getConstant(), getKind());
102 // Custom fixup types are not valid with symbol difference expressions.
103 return Res.getSymB() ? getKind() == VK_RISCV_None : true;
104}
105
107 Streamer.visitUsedExpr(*getSubExpr());
108}
109
112 .Case("lo", VK_RISCV_LO)
113 .Case("hi", VK_RISCV_HI)
114 .Case("pcrel_lo", VK_RISCV_PCREL_LO)
115 .Case("pcrel_hi", VK_RISCV_PCREL_HI)
116 .Case("got_pcrel_hi", VK_RISCV_GOT_HI)
117 .Case("tprel_lo", VK_RISCV_TPREL_LO)
118 .Case("tprel_hi", VK_RISCV_TPREL_HI)
119 .Case("tprel_add", VK_RISCV_TPREL_ADD)
120 .Case("tls_ie_pcrel_hi", VK_RISCV_TLS_GOT_HI)
121 .Case("tls_gd_pcrel_hi", VK_RISCV_TLS_GD_HI)
122 .Case("tlsdesc_hi", VK_RISCV_TLSDESC_HI)
123 .Case("tlsdesc_load_lo", VK_RISCV_TLSDESC_LOAD_LO)
124 .Case("tlsdesc_add_lo", VK_RISCV_TLSDESC_ADD_LO)
125 .Case("tlsdesc_call", VK_RISCV_TLSDESC_CALL)
127}
128
130 switch (Kind) {
131 case VK_RISCV_Invalid:
132 case VK_RISCV_None:
133 llvm_unreachable("Invalid ELF symbol kind");
134 case VK_RISCV_LO:
135 return "lo";
136 case VK_RISCV_HI:
137 return "hi";
139 return "pcrel_lo";
141 return "pcrel_hi";
142 case VK_RISCV_GOT_HI:
143 return "got_pcrel_hi";
145 return "tprel_lo";
147 return "tprel_hi";
149 return "tprel_add";
151 return "tls_ie_pcrel_hi";
153 return "tlsdesc_hi";
155 return "tlsdesc_load_lo";
157 return "tlsdesc_add_lo";
159 return "tlsdesc_call";
161 return "tls_gd_pcrel_hi";
162 case VK_RISCV_CALL:
163 return "call";
165 return "call_plt";
167 return "32_pcrel";
168 }
169 llvm_unreachable("Invalid ELF symbol kind");
170}
171
172static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm) {
173 switch (Expr->getKind()) {
174 case MCExpr::Target:
175 llvm_unreachable("Can't handle nested target expression");
176 break;
177 case MCExpr::Constant:
178 break;
179
180 case MCExpr::Binary: {
181 const MCBinaryExpr *BE = cast<MCBinaryExpr>(Expr);
184 break;
185 }
186
187 case MCExpr::SymbolRef: {
188 // We're known to be under a TLS fixup, so any symbol should be
189 // modified. There should be only one.
190 const MCSymbolRefExpr &SymRef = *cast<MCSymbolRefExpr>(Expr);
191 cast<MCSymbolELF>(SymRef.getSymbol()).setType(ELF::STT_TLS);
192 break;
193 }
194
195 case MCExpr::Unary:
196 fixELFSymbolsInTLSFixupsImpl(cast<MCUnaryExpr>(Expr)->getSubExpr(), Asm);
197 break;
198 }
199}
200
202 switch (getKind()) {
203 default:
204 return;
209 break;
210 }
211
213}
214
215bool RISCVMCExpr::evaluateAsConstant(int64_t &Res) const {
217
218 if (Kind == VK_RISCV_PCREL_HI || Kind == VK_RISCV_PCREL_LO ||
219 Kind == VK_RISCV_GOT_HI || Kind == VK_RISCV_TPREL_HI ||
220 Kind == VK_RISCV_TPREL_LO || Kind == VK_RISCV_TPREL_ADD ||
221 Kind == VK_RISCV_TLS_GOT_HI || Kind == VK_RISCV_TLS_GD_HI ||
224 Kind == VK_RISCV_CALL || Kind == VK_RISCV_CALL_PLT)
225 return false;
226
227 if (!getSubExpr()->evaluateAsRelocatable(Value, nullptr, nullptr))
228 return false;
229
230 if (!Value.isAbsolute())
231 return false;
232
233 Res = evaluateAsInt64(Value.getConstant());
234 return true;
235}
236
237int64_t RISCVMCExpr::evaluateAsInt64(int64_t Value) const {
238 switch (Kind) {
239 default:
240 llvm_unreachable("Invalid kind");
241 case VK_RISCV_LO:
242 return SignExtend64<12>(Value);
243 case VK_RISCV_HI:
244 // Add 1 if bit 11 is 1, to compensate for low 12 bits being negative.
245 return ((Value + 0x800) >> 12) & 0xfffff;
246 }
247}
static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm)
static RegisterPass< DebugifyFunctionPass > DF("debugify-function", "Attach debug info to a function")
#define F(x, y, z)
Definition: MD5.cpp:55
PowerPC TLS Dynamic Call Fixup
static const char * name
Definition: SMEABIPass.cpp:50
raw_pwrite_stream & OS
This class is intended to be used as a base class for asm properties and features specific to the tar...
Definition: MCAsmInfo.h:56
Binary assembler expressions.
Definition: MCExpr.h:488
const MCExpr * getLHS() const
Get the left-hand side expression of the binary operator.
Definition: MCExpr.h:635
const MCExpr * getRHS() const
Get the right-hand side expression of the binary operator.
Definition: MCExpr.h:638
Context object for machine code objects.
Definition: MCContext.h:83
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:34
@ Unary
Unary expressions.
Definition: MCExpr.h:40
@ Constant
Constant expressions.
Definition: MCExpr.h:38
@ SymbolRef
References to labels and assigned expressions.
Definition: MCExpr.h:39
@ Target
Target specific expression.
Definition: MCExpr.h:41
@ Binary
Binary expressions.
Definition: MCExpr.h:37
bool evaluateAsRelocatable(MCValue &Res, const MCAssembler *Asm, const MCFixup *Fixup) const
Try to evaluate the expression to a relocatable value, i.e.
Definition: MCExpr.cpp:788
void print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens=false) const
Definition: MCExpr.cpp:40
ExprKind getKind() const
Definition: MCExpr.h:78
Encode information on a single operation to perform on a byte sequence (e.g., an encoded instruction)...
Definition: MCFixup.h:71
Streaming machine code generation interface.
Definition: MCStreamer.h:213
void visitUsedExpr(const MCExpr &Expr)
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:188
const MCSymbol & getSymbol() const
Definition: MCExpr.h:406
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
uint64_t getOffset() const
Definition: MCSymbol.h:327
MCFragment * getFragment(bool SetUsed=true) const
Definition: MCSymbol.h:397
This represents an "assembler immediate".
Definition: MCValue.h:36
int64_t getConstant() const
Definition: MCValue.h:43
static MCValue get(const MCSymbolRefExpr *SymA, const MCSymbolRefExpr *SymB=nullptr, int64_t Val=0, uint32_t RefKind=0)
Definition: MCValue.h:59
const MCSymbolRefExpr * getSymB() const
Definition: MCValue.h:45
const MCSymbolRefExpr * getSymA() const
Definition: MCValue.h:44
VariantKind getKind() const
Definition: RISCVMCExpr.h:60
void fixELFSymbolsInTLSFixups(MCAssembler &Asm) const override
static const RISCVMCExpr * create(const MCExpr *Expr, VariantKind Kind, MCContext &Ctx)
Definition: RISCVMCExpr.cpp:30
void printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const override
Definition: RISCVMCExpr.cpp:35
const MCFixup * getPCRelHiFixup(const MCFragment **DFOut) const
Get the corresponding PC-relative HI fixup that a VK_RISCV_PCREL_LO points to, and optionally the fra...
Definition: RISCVMCExpr.cpp:47
void visitUsedExpr(MCStreamer &Streamer) const override
bool evaluateAsConstant(int64_t &Res) const
static StringRef getVariantKindName(VariantKind Kind)
bool evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm, const MCFixup *Fixup) const override
Definition: RISCVMCExpr.cpp:91
const MCExpr * getSubExpr() const
Definition: RISCVMCExpr.h:62
static VariantKind getVariantKindForName(StringRef name)
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
A switch()-like statement whose cases are string literals.
Definition: StringSwitch.h:44
StringSwitch & Case(StringLiteral S, T Value)
Definition: StringSwitch.h:69
R Default(T Value)
Definition: StringSwitch.h:182
LLVM Value Representation.
Definition: Value.h:74
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
@ STT_TLS
Definition: ELF.h:1357
@ fixup_riscv_tls_got_hi20
@ fixup_riscv_tlsdesc_hi20
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
@ Offset
Definition: DWP.cpp:480