LLVM 19.0.0git
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/MCAsmLayout.h"
19#include "llvm/MC/MCAssembler.h"
20#include "llvm/MC/MCContext.h"
21#include "llvm/MC/MCStreamer.h"
22#include "llvm/MC/MCSymbolELF.h"
23#include "llvm/MC/MCValue.h"
26
27using namespace llvm;
28
29#define DEBUG_TYPE "riscvmcexpr"
30
32 MCContext &Ctx) {
33 return new (Ctx) RISCVMCExpr(Expr, Kind);
34}
35
37 VariantKind Kind = getKind();
38 bool HasVariant = ((Kind != VK_RISCV_None) && (Kind != VK_RISCV_CALL) &&
39 (Kind != VK_RISCV_CALL_PLT));
40
41 if (HasVariant)
42 OS << '%' << getVariantKindName(getKind()) << '(';
43 Expr->print(OS, MAI);
44 if (HasVariant)
45 OS << ')';
46}
47
48const MCFixup *RISCVMCExpr::getPCRelHiFixup(const MCFragment **DFOut) const {
49 MCValue AUIPCLoc;
50 if (!getSubExpr()->evaluateAsRelocatable(AUIPCLoc, nullptr, nullptr))
51 return nullptr;
52
53 const MCSymbolRefExpr *AUIPCSRE = AUIPCLoc.getSymA();
54 if (!AUIPCSRE)
55 return nullptr;
56
57 const MCSymbol *AUIPCSymbol = &AUIPCSRE->getSymbol();
58 const auto *DF = dyn_cast_or_null<MCDataFragment>(AUIPCSymbol->getFragment());
59
60 if (!DF)
61 return nullptr;
62
63 uint64_t Offset = AUIPCSymbol->getOffset();
64 if (DF->getContents().size() == Offset) {
65 DF = dyn_cast_or_null<MCDataFragment>(DF->getNextNode());
66 if (!DF)
67 return nullptr;
68 Offset = 0;
69 }
70
71 for (const MCFixup &F : DF->getFixups()) {
72 if (F.getOffset() != Offset)
73 continue;
74
75 switch ((unsigned)F.getKind()) {
76 default:
77 continue;
83 if (DFOut)
84 *DFOut = DF;
85 return &F;
86 }
87 }
88
89 return nullptr;
90}
91
93 const MCAsmLayout *Layout,
94 const MCFixup *Fixup) const {
95 // Explicitly drop the layout and assembler to prevent any symbolic folding in
96 // the expression handling. This is required to preserve symbolic difference
97 // expressions to emit the paired relocations.
98 if (!getSubExpr()->evaluateAsRelocatable(Res, nullptr, nullptr))
99 return false;
100
101 Res =
102 MCValue::get(Res.getSymA(), Res.getSymB(), Res.getConstant(), getKind());
103 // Custom fixup types are not valid with symbol difference expressions.
104 return Res.getSymB() ? getKind() == VK_RISCV_None : true;
105}
106
108 Streamer.visitUsedExpr(*getSubExpr());
109}
110
113 .Case("lo", VK_RISCV_LO)
114 .Case("hi", VK_RISCV_HI)
115 .Case("pcrel_lo", VK_RISCV_PCREL_LO)
116 .Case("pcrel_hi", VK_RISCV_PCREL_HI)
117 .Case("got_pcrel_hi", VK_RISCV_GOT_HI)
118 .Case("tprel_lo", VK_RISCV_TPREL_LO)
119 .Case("tprel_hi", VK_RISCV_TPREL_HI)
120 .Case("tprel_add", VK_RISCV_TPREL_ADD)
121 .Case("tls_ie_pcrel_hi", VK_RISCV_TLS_GOT_HI)
122 .Case("tls_gd_pcrel_hi", VK_RISCV_TLS_GD_HI)
123 .Case("tlsdesc_hi", VK_RISCV_TLSDESC_HI)
124 .Case("tlsdesc_load_lo", VK_RISCV_TLSDESC_LOAD_LO)
125 .Case("tlsdesc_add_lo", VK_RISCV_TLSDESC_ADD_LO)
126 .Case("tlsdesc_call", VK_RISCV_TLSDESC_CALL)
128}
129
131 switch (Kind) {
132 case VK_RISCV_Invalid:
133 case VK_RISCV_None:
134 llvm_unreachable("Invalid ELF symbol kind");
135 case VK_RISCV_LO:
136 return "lo";
137 case VK_RISCV_HI:
138 return "hi";
140 return "pcrel_lo";
142 return "pcrel_hi";
143 case VK_RISCV_GOT_HI:
144 return "got_pcrel_hi";
146 return "tprel_lo";
148 return "tprel_hi";
150 return "tprel_add";
152 return "tls_ie_pcrel_hi";
154 return "tlsdesc_hi";
156 return "tlsdesc_load_lo";
158 return "tlsdesc_add_lo";
160 return "tlsdesc_call";
162 return "tls_gd_pcrel_hi";
163 case VK_RISCV_CALL:
164 return "call";
166 return "call_plt";
168 return "32_pcrel";
169 }
170 llvm_unreachable("Invalid ELF symbol kind");
171}
172
173static void fixELFSymbolsInTLSFixupsImpl(const MCExpr *Expr, MCAssembler &Asm) {
174 switch (Expr->getKind()) {
175 case MCExpr::Target:
176 llvm_unreachable("Can't handle nested target expression");
177 break;
178 case MCExpr::Constant:
179 break;
180
181 case MCExpr::Binary: {
182 const MCBinaryExpr *BE = cast<MCBinaryExpr>(Expr);
185 break;
186 }
187
188 case MCExpr::SymbolRef: {
189 // We're known to be under a TLS fixup, so any symbol should be
190 // modified. There should be only one.
191 const MCSymbolRefExpr &SymRef = *cast<MCSymbolRefExpr>(Expr);
192 cast<MCSymbolELF>(SymRef.getSymbol()).setType(ELF::STT_TLS);
193 break;
194 }
195
196 case MCExpr::Unary:
197 fixELFSymbolsInTLSFixupsImpl(cast<MCUnaryExpr>(Expr)->getSubExpr(), Asm);
198 break;
199 }
200}
201
203 switch (getKind()) {
204 default:
205 return;
210 break;
211 }
212
214}
215
216bool RISCVMCExpr::evaluateAsConstant(int64_t &Res) const {
218
219 if (Kind == VK_RISCV_PCREL_HI || Kind == VK_RISCV_PCREL_LO ||
220 Kind == VK_RISCV_GOT_HI || Kind == VK_RISCV_TPREL_HI ||
221 Kind == VK_RISCV_TPREL_LO || Kind == VK_RISCV_TPREL_ADD ||
222 Kind == VK_RISCV_TLS_GOT_HI || Kind == VK_RISCV_TLS_GD_HI ||
225 Kind == VK_RISCV_CALL || Kind == VK_RISCV_CALL_PLT)
226 return false;
227
228 if (!getSubExpr()->evaluateAsRelocatable(Value, nullptr, nullptr))
229 return false;
230
231 if (!Value.isAbsolute())
232 return false;
233
234 Res = evaluateAsInt64(Value.getConstant());
235 return true;
236}
237
238int64_t RISCVMCExpr::evaluateAsInt64(int64_t Value) const {
239 switch (Kind) {
240 default:
241 llvm_unreachable("Invalid kind");
242 case VK_RISCV_LO:
243 return SignExtend64<12>(Value);
244 case VK_RISCV_HI:
245 // Add 1 if bit 11 is 1, to compensate for low 12 bits being negative.
246 return ((Value + 0x800) >> 12) & 0xfffff;
247 }
248}
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:49
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
Encapsulates the layout of an assembly file at a particular point in time.
Definition: MCAsmLayout.h:28
Binary assembler expressions.
Definition: MCExpr.h:492
const MCExpr * getLHS() const
Get the left-hand side expression of the binary operator.
Definition: MCExpr.h:639
const MCExpr * getRHS() const
Get the right-hand side expression of the binary operator.
Definition: MCExpr.h:642
Context object for machine code objects.
Definition: MCContext.h:76
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
@ Unary
Unary expressions.
Definition: MCExpr.h:41
@ Constant
Constant expressions.
Definition: MCExpr.h:39
@ SymbolRef
References to labels and assigned expressions.
Definition: MCExpr.h:40
@ Target
Target specific expression.
Definition: MCExpr.h:42
@ Binary
Binary expressions.
Definition: MCExpr.h:38
bool evaluateAsRelocatable(MCValue &Res, const MCAsmLayout *Layout, const MCFixup *Fixup) const
Try to evaluate the expression to a relocatable value, i.e.
Definition: MCExpr.cpp:814
void print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens=false) const
Definition: MCExpr.cpp:41
ExprKind getKind() const
Definition: MCExpr.h:81
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:212
void visitUsedExpr(const MCExpr &Expr)
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:192
const MCSymbol & getSymbol() const
Definition: MCExpr.h:410
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:40
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:31
void printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const override
Definition: RISCVMCExpr.cpp:36
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:48
void visitUsedExpr(MCStreamer &Streamer) const override
bool evaluateAsConstant(int64_t &Res) const
static StringRef getVariantKindName(VariantKind Kind)
const MCExpr * getSubExpr() const
Definition: RISCVMCExpr.h:62
bool evaluateAsRelocatableImpl(MCValue &Res, const MCAsmLayout *Layout, const MCFixup *Fixup) const override
Definition: RISCVMCExpr.cpp:92
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:1328
@ 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:456