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AArch64: Replace @plt/%gotpcrel in data directives with %pltpcrel %gotpcrel (#155776)

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Similar to #132569 for RISC-V, replace the unofficial `@plt` and
`@gotpcrel` relocation specifiers, currently only used by clang
-fexperimental-relative-c++-abi-vtables, with %pltpcrel %gotpcrel. The
syntax is not used in humand-written assembly code, and is not supported
by GNU assembler.

Also replace the recent `@funcinit` with `%funcinit(x)`.
This commit is contained in:
Fangrui Song 2026-02-27 21:37:59 -08:00 committed by GitHub
parent ce6a3d98cc
commit bed89970c3
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
17 changed files with 141 additions and 80 deletions
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2
bolt/test/AArch64/skip-non-vfuncptr-reloc-in-relative-vtable.s
View File

@ -31,5 +31,5 @@ _fake_rtti_data:
_ZTV3gooE:
.word 0
.word _fake_rtti_data-_ZTV3gooE-8
.word foo@PLT-_ZTV3gooE-8
.word %pltpcrel(foo)
.size _ZTV3gooE, 12

6
lld/test/ELF/aarch64-branch-to-branch.s
View File

@ -35,14 +35,14 @@ vtable:
# B2B-NEXT: [[VF:[0-9a-f]{8}]]
# B2B-RELOC-NEXT: R_AARCH64_PLT32 f3
# NOB2B-RELOC-NEXT: R_AARCH64_PLT32 f1
.4byte f1@PLT - vtable
.4byte %pltpcrel(f1)
# B2B-SAME: [[VF]]
# B2B-RELOC-NEXT: R_AARCH64_PLT32 f3+0x4
# NOB2B-RELOC-NEXT: R_AARCH64_PLT32 f2+0x4
.4byte f2@PLT - vtable
.4byte %pltpcrel(f2+4)
# B2B-SAME: [[VF]]
# RELOC-NEXT: R_AARCH64_PLT32 f3+0x8
.4byte f3@PLT - vtable
.4byte %pltpcrel(f3+8)
.section .text._start,"ax"
.globl _start

2
lld/test/ELF/aarch64-feature-bti.s
View File

@ -290,5 +290,5 @@ func1:
.ifdef RELVTABLE_PLT
// R_AARCH64_PLT32
.word funcRelVtable@PLT - .
.word %pltpcrel(funcRelVtable)
.endif

4
lld/test/ELF/aarch64-funcinit64-invalid.s
View File

@ -5,11 +5,11 @@
.rodata
# ERR: error: relocation R_AARCH64_FUNCINIT64 cannot be used against local symbol
.8byte func@FUNCINIT
.8byte %funcinit(func)
.data
# ERR: error: relocation R_AARCH64_FUNCINIT64 cannot be used against ifunc symbol 'ifunc'
.8byte ifunc@FUNCINIT
.8byte %funcinit(ifunc)
.text
func:

2
lld/test/ELF/aarch64-funcinit64.s
View File

@ -10,7 +10,7 @@
.data
# CHECK: R_AARCH64_IRELATIVE [[FOO:[0-9a-f]*]]
# ERR: relocation R_AARCH64_FUNCINIT64 cannot be used against preemptible symbol 'foo'
.8byte foo@FUNCINIT
.8byte %funcinit(foo)
.text
# CHECK: {{0*}}[[FOO]] {{.*}} foo

2
lld/test/ELF/aarch64-range-thunk-extension-plt32.s
View File

@ -25,7 +25,7 @@
.global _start
.type _start, %function
_start:
.word callee@PLT - .
.word %pltpcrel(callee)
.section .text.2, "ax", %progbits
.global callee

10
lld/test/ELF/aarch64-reloc-gotpcrel32.s
View File

@ -17,11 +17,11 @@ _start: // PC = 0x303a0
// bar@GOTPCREL-4 = 0x20390 (got entry for `bar`) - 0x303a8 (.) - 4 = 0xe4fffeff
// CHECK: Contents of section .data:
// CHECK-NEXT: {{.*}} f0fffeff f0fffeff e4fffeff
.word bar@GOTPCREL
.word bar@GOTPCREL+4
.word bar@GOTPCREL-4
.word %gotpcrel(bar)
.word %gotpcrel(bar+4)
.word %gotpcrel(bar-4)
// WARN: relocation R_AARCH64_GOTPCREL32 out of range: {{.*}} is not in [-2147483648, 2147483647]; references 'baz'
// WARN: relocation R_AARCH64_GOTPCREL32 out of range: {{.*}} is not in [-2147483648, 2147483647]; references 'baz'
.word baz@GOTPCREL+0xffffffff
.word baz@GOTPCREL-0xffffffff
.word %gotpcrel(baz+0xffffffff)
.word %gotpcrel(baz-0xffffffff)

6
lld/test/ELF/aarch64-reloc-plt32.s
View File

@ -32,6 +32,6 @@
.globl _start
_start:
.data
.word foo@PLT - . + 2149589079
.word foo@PLT - . - 2145378212
.word foo@PLT - .
.word %pltpcrel(foo + 2149589079)
.word %pltpcrel(foo - 2145378212)
.word %pltpcrel(foo)

2
lld/test/ELF/aarch64-undefined-weak.s
View File

@ -37,7 +37,7 @@ _start:
// R_AARCH64_PREL16
.hword target - .
// R_AARCH64_PLT32
.word target@PLT - .
.word %pltpcrel(target)
bl_undefweak2:
bl undefweak2

5
llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
View File

@ -2671,8 +2671,9 @@ const MCExpr *AArch64AsmPrinter::emitPAuthRelocationAsIRelative(
MCInstBuilder(AArch64::RET).addReg(AArch64::LR), *STI);
OutStreamer->popSection();
return MCSymbolRefExpr::create(IRelativeSym, AArch64::S_FUNCINIT,
OutStreamer->getContext());
return MCSpecifierExpr::create(
MCSymbolRefExpr::create(IRelativeSym, OutStreamer->getContext()),
AArch64::S_FUNCINIT, OutStreamer->getContext());
}
const MCExpr *

32
llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
View File

@ -182,6 +182,7 @@ private:
bool showMatchError(SMLoc Loc, unsigned ErrCode, uint64_t ErrorInfo,
OperandVector &Operands);
bool parseExprWithSpecifier(const MCExpr *&Res, SMLoc &E);
bool parseDataExpr(const MCExpr *&Res) override;
bool parseAuthExpr(const MCExpr *&Res, SMLoc &EndLoc);
@ -8452,8 +8453,31 @@ bool AArch64AsmParser::parseDirectiveAeabiAArch64Attr(SMLoc L) {
return false;
}
bool AArch64AsmParser::parseExprWithSpecifier(const MCExpr *&Res, SMLoc &E) {
SMLoc Loc = getLoc();
if (getLexer().getKind() != AsmToken::Identifier)
return TokError("expected '%' relocation specifier");
StringRef Identifier = getParser().getTok().getIdentifier();
auto Spec = AArch64::parsePercentSpecifierName(Identifier);
if (!Spec)
return TokError("invalid relocation specifier");
getParser().Lex(); // Eat the identifier
if (parseToken(AsmToken::LParen, "expected '('"))
return true;
const MCExpr *SubExpr;
if (getParser().parseParenExpression(SubExpr, E))
return true;
Res = MCSpecifierExpr::create(SubExpr, Spec, getContext(), Loc);
return false;
}
bool AArch64AsmParser::parseDataExpr(const MCExpr *&Res) {
SMLoc EndLoc;
if (parseOptionalToken(AsmToken::Percent))
return parseExprWithSpecifier(Res, EndLoc);
if (getParser().parseExpression(Res))
return true;
@ -8473,14 +8497,6 @@ bool AArch64AsmParser::parseDataExpr(const MCExpr *&Res) {
if (STI->getTargetTriple().isOSBinFormatMachO()) {
if (Identifier == "got")
Spec = AArch64::S_MACHO_GOT;
} else {
// Unofficial, experimental syntax that will be changed.
if (Identifier == "gotpcrel")
Spec = AArch64::S_GOTPCREL;
else if (Identifier == "plt")
Spec = AArch64::S_PLT;
else if (Identifier == "funcinit")
Spec = AArch64::S_FUNCINIT;
}
if (Spec == AArch64::S_None)
return Error(Loc, "invalid relocation specifier");

27
llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
View File

@ -104,6 +104,20 @@ unsigned AArch64ELFObjectWriter::getRelocType(const MCFixup &Fixup,
break;
}
switch (RefKind) {
case AArch64::S_GOTPCREL:
case AArch64::S_PLT:
if (Kind == FK_Data_4)
break;
// Only R_AARCH64_PLT32/R_AARCH64_GOTPCREL32 defined at present, but can
// be extended to other sizes if additional relocations are defined.
reportError(Fixup.getLoc(), AArch64::getSpecifierName(RefKind) +
" can only be used in a .word directive");
return ELF::R_AARCH64_NONE;
default:
break;
}
// Extract the relocation type from the fixup kind, after applying STT_TLS as
// needed.
if (mc::isRelocation(Fixup.getKind()))
@ -117,8 +131,7 @@ unsigned AArch64ELFObjectWriter::getRelocType(const MCFixup &Fixup,
case FK_Data_2:
return R_CLS(PREL16);
case FK_Data_4: {
return Target.getSpecifier() == AArch64::S_PLT ? R_CLS(PLT32)
: R_CLS(PREL32);
return R_CLS(PREL32);
}
case FK_Data_8:
if (IsILP32) {
@ -220,9 +233,13 @@ unsigned AArch64ELFObjectWriter::getRelocType(const MCFixup &Fixup,
case FK_Data_2:
return R_CLS(ABS16);
case FK_Data_4:
return (!IsILP32 && Target.getSpecifier() == AArch64::S_GOTPCREL)
? ELF::R_AARCH64_GOTPCREL32
: R_CLS(ABS32);
if (!IsILP32) {
if (Target.getSpecifier() == AArch64::S_GOTPCREL)
return ELF::R_AARCH64_GOTPCREL32;
if (Target.getSpecifier() == AArch64::S_PLT)
return ELF::R_AARCH64_PLT32;
}
return R_CLS(ABS32);
case FK_Data_8: {
if (IsILP32) {
reportError(

19
llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp
View File

@ -114,12 +114,24 @@ StringRef AArch64::getSpecifierName(AArch64::Specifier S) {
case AArch64::S_GOT_AUTH: return ":got_auth:";
case AArch64::S_GOT_AUTH_PAGE: return ":got_auth:";
case AArch64::S_GOT_AUTH_LO12: return ":got_auth_lo12:";
case AArch64::S_GOTPCREL: return "%gotpcrel";
case AArch64::S_PLT: return "%pltpcrel";
case AArch64::S_FUNCINIT: return "%funcinit";
default:
llvm_unreachable("Invalid relocation specifier");
}
// clang-format on
}
AArch64::Specifier AArch64::parsePercentSpecifierName(StringRef name) {
return StringSwitch<AArch64::Specifier>(name)
.Case("pltpcrel", AArch64::S_PLT)
.Case("gotpcrel", AArch64::S_GOTPCREL)
.Case("funcinit", AArch64::S_FUNCINIT)
.Default(0);
}
static bool evaluate(const MCSpecifierExpr &Expr, MCValue &Res,
const MCAssembler *Asm) {
if (!Expr.getSubExpr()->evaluateAsRelocatable(Res, Asm))
@ -232,8 +244,13 @@ void AArch64MCAsmInfoELF::printSpecifierExpr(
raw_ostream &OS, const MCSpecifierExpr &Expr) const {
if (auto *AE = dyn_cast<AArch64AuthMCExpr>(&Expr))
return AE->print(OS, this);
OS << AArch64::getSpecifierName(Expr.getSpecifier());
auto Str = AArch64::getSpecifierName(Expr.getSpecifier());
OS << Str;
if (!Str.empty() && Str[0] == '%')
OS << '(';
printExpr(OS, *Expr.getSubExpr());
if (!Str.empty() && Str[0] == '%')
OS << ')';
}
bool AArch64MCAsmInfoELF::evaluateAsRelocatableImpl(

2
llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.h
View File

@ -184,6 +184,8 @@ enum {
/// (e.g. ":got:", ":lo12:").
StringRef getSpecifierName(Specifier S);
Specifier parsePercentSpecifierName(StringRef);
inline Specifier getSymbolLoc(Specifier S) {
return static_cast<Specifier>(S & AArch64::S_SymLocBits);
}

18
llvm/test/CodeGen/AArch64/ptrauth-irelative.ll
View File

@ -8,7 +8,7 @@
; CHECK-NEXT: mov x1, #1
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .rodata
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@nullref = constant ptr ptrauth (ptr null, i32 2, i64 1, ptr null), align 8
@dsolocal = external dso_local global i8
@ -22,7 +22,7 @@
; CHECK-NEXT: mov x1, #2
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@dsolocalref = constant ptr ptrauth (ptr @dsolocal, i32 2, i64 2, ptr null), align 8
@ds = external global i8
@ -39,7 +39,7 @@
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: ret
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@dsolocalrefds = constant ptr ptrauth (ptr @dsolocal, i32 2, i64 2, ptr null, ptr @ds), align 8
; CHECK: dsolocalref8:
@ -51,7 +51,7 @@
; CHECK-NEXT: mov x1, #3
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@dsolocalref8 = constant ptr ptrauth (ptr getelementptr (i8, ptr @dsolocal, i64 8), i32 2, i64 3, ptr null), align 8
; CHECK: disc:
@ -64,7 +64,7 @@
; CHECK-NEXT: add x1, x1, :lo12:[[PLACE]]
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@disc = constant ptr ptrauth (ptr @dsolocal, i32 2, i64 0, ptr @disc), align 8
; CHECK: disc65536:
@ -77,7 +77,7 @@
; CHECK-NEXT: add x1, x1, :lo12:[[PLACE]]+65536
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@disc65536 = constant ptr ptrauth (ptr @dsolocal, i32 2, i64 65536, ptr @disc), align 8
@global = external global i8
@ -91,7 +91,7 @@
; CHECK-NEXT: mov x1, #4
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@globalref = constant ptr ptrauth (ptr @global, i32 2, i64 4, ptr null), align 8
; CHECK: globalref8:
@ -104,7 +104,7 @@
; CHECK-NEXT: mov x1, #5
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@globalref8 = constant ptr ptrauth (ptr getelementptr (i8, ptr @global, i64 8), i32 2, i64 5, ptr null), align 8
; CHECK: globalref16777216:
@ -119,7 +119,7 @@
; CHECK-NEXT: mov x1, #5
; CHECK-NEXT: b __emupac_pacda
; CHECK-NEXT: .section .data.rel.ro
; CHECK-NEXT: .xword [[FUNC]]@FUNCINIT
; CHECK-NEXT: .xword %funcinit([[FUNC]])
@globalref16777216 = constant ptr ptrauth (ptr getelementptr (i8, ptr @global, i64 16777216), i32 2, i64 5, ptr null), align 8
$comdat = comdat any

80
llvm/test/MC/AArch64/data-directive-specifier.s
View File

@ -1,57 +1,65 @@
# RUN: llvm-mc -triple=aarch64 %s | FileCheck %s --check-prefix=ASM
# RUN: llvm-mc -triple=aarch64 -filetype=obj %s | llvm-readobj -r - | FileCheck %s
# RUN: not llvm-mc -triple=aarch64 %s --defsym ERR=1 -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERR --implicit-check-not=error:
# RUN: not llvm-mc -triple=aarch64 -filetype=obj %s --defsym OBJERR=1 -o /dev/null 2>&1 | FileCheck %s --check-prefix=OBJERR --implicit-check-not=error:
# RUN: not llvm-mc -triple=aarch64 %s --defsym ERR0=1 2>&1 | FileCheck %s --check-prefix=ERR0 --implicit-check-not=error:
# RUN: not llvm-mc -triple=aarch64 -filetype=obj %s --defsym ERR=1 -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERR --implicit-check-not=error:
.globl g
g:
l:
# ASM: .word %pltpcrel(l)
# CHECK: Section ({{.*}}) .rela.data {
# CHECK-NEXT: 0x0 R_AARCH64_PLT32 l 0x0
# CHECK-NEXT: 0x4 R_AARCH64_PLT32 l 0x4
# CHECK-NEXT: 0x8 R_AARCH64_PLT32 extern 0x4
# CHECK-NEXT: 0xC R_AARCH64_PLT32 g 0x8
# CHECK-NEXT: 0x10 R_AARCH64_PLT32 g 0x18
# CHECK-NEXT: 0x14 R_AARCH64_FUNCINIT64 .text 0x0
# CHECK-NEXT: 0x4 R_AARCH64_PLT32 extern 0x4
# CHECK-NEXT: 0x8 R_AARCH64_PLT32 g 0x8
# CHECK-NEXT: }
.data
.word l@plt - .
.word l@plt - .data
.word extern@plt - . + 4
.word g@plt - . + 8
.word g@plt - .data + 8
.quad l@funcinit
.word %pltpcrel(l)
.word %pltpcrel(extern + 4), %pltpcrel(g + 8)
# ASM: .word %gotpcrel(data1)
# CHECK: Section ({{.*}}) .rela.data1 {
# CHECK-NEXT: 0x0 R_AARCH64_GOTPCREL32 data1 0x0
# CHECK-NEXT: 0x4 R_AARCH64_GOTPCREL32 extern 0x4
# CHECK-NEXT: 0x8 R_AARCH64_GOTPCREL32 extern 0xFFFFFFFFFFFFFFFB
# CHECK-NEXT: 0x8 R_AARCH64_GOTPCREL32 extern 0xFFFFFFFFFFFFFFFB
# CHECK-NEXT: 0xC R_AARCH64_FUNCINIT64 .text 0
# CHECK-NEXT: }
.section .data1,"aw"
data1:
.word data1@GOTPCREL
.word extern@gotpcrel+4
.word extern@GOTPCREL-5
.word %gotpcrel(data1)
.word %gotpcrel(extern+4), %gotpcrel(extern-5)
.quad %funcinit(l)
.ifdef ERR0
# ERR0: [[#@LINE+1]]:8: error: invalid relocation specifier
.word %xxx(l)
# ERR0: [[#@LINE+1]]:17: error: expected '('
.word %pltpcrel l
# ERR0: [[#@LINE+2]]:14: error: unknown token in expression
# ERR0: [[#@LINE+1]]:14: error: invalid operand
ldr w0, [x1, %pltpcrel(g)]
.endif
## Test parse-time errors
.ifdef ERR
# ERR: [[#@LINE+1]]:9: error: @ specifier only allowed after a symbol
.quad 3@plt - .
# ERR: [[#@LINE+1]]:8: error: %pltpcrel can only be used in a .word directive
.quad %pltpcrel(g)
# ERR: [[#@LINE+1]]:9: error: expected ')'
.quad (l@plt - .)
.endif
.ifdef OBJERR
.quad g@plt - .
.word extern@gotpcrel - .
# OBJERR: [[#@LINE+1]]:7: error: symbol 'und' can not be undefined in a subtraction expression
.word extern@plt - und
# OBJERR: [[#@LINE+1]]:7: error: symbol 'und' can not be undefined in a subtraction expression
.word extern@gotpcrel - und
# ERR: [[#@LINE+1]]:8: error: expected relocatable expression
.word %pltpcrel(g-.)
# ERR: [[#@LINE+1]]:8: error: expected relocatable expression
.word %pltpcrel(extern - und)
# ERR: [[#@LINE+1]]:8: error: %gotpcrel can only be used in a .word directive
.quad %gotpcrel(g)
# ERR: [[#@LINE+1]]:8: error: expected relocatable expression
.word %gotpcrel(extern - .)
# ERR: [[#@LINE+1]]:8: error: expected relocatable expression
.word %gotpcrel(extern - und)
.endif

2
llvm/test/MC/AArch64/elf-reloc-ptrauth.s
View File

@ -125,7 +125,7 @@ _g9:
// ERR: :[[#@LINE+1]]:21: error: expected ')'
.quad sym@AUTH(ia,42(
// ERR: :[[#@LINE+1]]:14: error: unexpected token
// ERR: :[[#@LINE+1]]:11: error: invalid relocation specifier
.quad sym@PLT@AUTH(ia,42)
// ERR: :[[#@LINE+1]]:15: error: expected '('