[clang] [llvm] [Clang][AArch64] Add support for SHF_AARCH64_PURECODE ELF section flag (2/3) (PR #125688)
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Tue Feb 4 06:14:27 PST 2025
=?utf-8?q?Csanád_Hajdú?= <csanad.hajdu at arm.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/125688 at github.com>
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-binary-utilities
Author: Csanád Hajdú (Il-Capitano)
<details>
<summary>Changes</summary>
Add support for the new SHF_AARCH64_PURECODE ELF section flag: https://github.com/ARM-software/abi-aa/pull/304
The general implementation follows the existing one for ARM targets. Simlarly to ARM targets, generating object files with the `SHF_AARCH64_PURECODE` flag set is enabled by the `-mexecute-only`/`-mpure-code` driver flag.
Depends on https://github.com/llvm/llvm-project/pull/125687. The changes in that PR are included here as well for now, but will be removed once that gets merged.
---
Patch is 26.08 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/125688.diff
23 Files Affected:
- (modified) clang/include/clang/Driver/Options.td (+2-2)
- (modified) clang/lib/Driver/ToolChains/Arch/AArch64.cpp (+11)
- (added) clang/test/CodeGen/aarch64-execute-only.c (+24)
- (added) clang/test/Driver/aarch64-execute-only.c (+6)
- (modified) clang/test/Driver/fsanitize.c (+7-1)
- (modified) llvm/include/llvm/BinaryFormat/ELF.h (+4-1)
- (modified) llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp (+8-5)
- (modified) llvm/lib/MC/MCParser/ELFAsmParser.cpp (+5-2)
- (modified) llvm/lib/MC/MCSectionELF.cpp (+3)
- (modified) llvm/lib/ObjectYAML/ELFYAML.cpp (+3)
- (modified) llvm/lib/Target/AArch64/AArch64Features.td (+5)
- (modified) llvm/lib/Target/AArch64/AArch64TargetObjectFile.cpp (+26)
- (modified) llvm/lib/Target/AArch64/AArch64TargetObjectFile.h (+6)
- (modified) llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp (+16-1)
- (modified) llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h (+2)
- (modified) llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp (+18)
- (added) llvm/test/CodeGen/AArch64/execute-only-section.ll (+21)
- (added) llvm/test/MC/ELF/AArch64/execute-only-populated-text-section.s (+27)
- (added) llvm/test/MC/ELF/AArch64/execute-only-section.s (+43)
- (added) llvm/test/MC/ELF/AArch64/execute-only-text-section-data.s (+27)
- (modified) llvm/test/MC/ELF/section-flags-unknown.s (+3)
- (modified) llvm/test/Transforms/Inline/AArch64/inline-target-attr.ll (+25)
- (modified) llvm/tools/llvm-readobj/ELFDumper.cpp (+8)
``````````diff
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 0ab923fcdd5838c..028d74c9711d1f0 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -4677,9 +4677,9 @@ def mno_long_calls : Flag<["-"], "mno-long-calls">, Group<m_Group>,
HelpText<"Restore the default behaviour of not generating long calls">;
} // let Flags = [TargetSpecific]
def mexecute_only : Flag<["-"], "mexecute-only">, Group<m_arm_Features_Group>,
- HelpText<"Disallow generation of data access to code sections (ARM only)">;
+ HelpText<"Disallow generation of data access to code sections (AArch64/ARM only)">;
def mno_execute_only : Flag<["-"], "mno-execute-only">, Group<m_arm_Features_Group>,
- HelpText<"Allow generation of data access to code sections (ARM only)">;
+ HelpText<"Allow generation of data access to code sections (AArch64/ARM only)">;
let Flags = [TargetSpecific] in {
def mtp_mode_EQ : Joined<["-"], "mtp=">, Group<m_arm_Features_Group>, Values<"soft,cp15,tpidrurw,tpidruro,tpidrprw,el0,el1,el2,el3,tpidr_el0,tpidr_el1,tpidr_el2,tpidr_el3,tpidrro_el0">,
HelpText<"Thread pointer access method. "
diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
index 1e2ac4e501bafd1..1248fea50f9de2b 100644
--- a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -332,6 +332,17 @@ void aarch64::getAArch64TargetFeatures(const Driver &D,
} else if (Triple.isOSOpenBSD())
Features.push_back("+strict-align");
+ // Generate execute-only output (no data access to code sections).
+ // This only makes sense for the compiler, not for the assembler.
+ if (!ForAS) {
+ if (Arg *A = Args.getLastArg(options::OPT_mexecute_only,
+ options::OPT_mno_execute_only)) {
+ if (A->getOption().matches(options::OPT_mexecute_only)) {
+ Features.push_back("+execute-only");
+ }
+ }
+ }
+
if (Args.hasArg(options::OPT_ffixed_x1))
Features.push_back("+reserve-x1");
diff --git a/clang/test/CodeGen/aarch64-execute-only.c b/clang/test/CodeGen/aarch64-execute-only.c
new file mode 100644
index 000000000000000..d885e954166f674
--- /dev/null
+++ b/clang/test/CodeGen/aarch64-execute-only.c
@@ -0,0 +1,24 @@
+// RUN: %clang -target aarch64 -### %s 2>&1 \
+// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+
+// RUN: %clang -target aarch64 -### -mexecute-only %s 2>&1 \
+// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY
+
+// RUN: %clang -target aarch64 -### -mexecute-only -mno-execute-only %s 2>&1 \
+// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+
+
+// -mpure-code flag for GCC compatibility
+// RUN: %clang -target aarch64 -### %s 2>&1 \
+// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+
+// RUN: %clang -target aarch64 -### -mpure-code %s 2>&1 \
+// RUN: | FileCheck %s -check-prefix CHECK-EXECUTE-ONLY
+
+// RUN: %clang -target aarch64 -### -mpure-code -mno-pure-code %s 2>&1 \
+// RUN: | FileCheck %s -check-prefix CHECK-NO-EXECUTE-ONLY
+
+// CHECK-NO-EXECUTE-ONLY-NOT: "+execute-only"
+// CHECK-EXECUTE-ONLY: "+execute-only"
+
+void a() {}
diff --git a/clang/test/Driver/aarch64-execute-only.c b/clang/test/Driver/aarch64-execute-only.c
new file mode 100644
index 000000000000000..67c6d4a5eb06699
--- /dev/null
+++ b/clang/test/Driver/aarch64-execute-only.c
@@ -0,0 +1,6 @@
+// RUN: %clang --sysroot=%S/Inputs -c -fdriver-only -Werror --target=aarch64-unknown-linux-gnu \
+// RUN: -mexecute-only %s 2>&1 | count 0
+
+// RUN: %clang -### --target=aarch64-unknown-linux-gnu -x assembler -mexecute-only %s -c -### 2>&1 \
+// RUN: | FileCheck %s --check-prefix=CHECK-NO-EXECUTE-ONLY-ASM
+// CHECK-NO-EXECUTE-ONLY-ASM: warning: argument unused during compilation: '-mexecute-only'
diff --git a/clang/test/Driver/fsanitize.c b/clang/test/Driver/fsanitize.c
index 429dc51b3356d68..cb3b75cbd27a7be 100644
--- a/clang/test/Driver/fsanitize.c
+++ b/clang/test/Driver/fsanitize.c
@@ -1052,7 +1052,6 @@
// RUN: not %clang --target=x86_64-sie-ps5 -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-TARGET
// RUN: not %clang --target=x86_64-sie-ps5 -fsanitize=function -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-TARGET --check-prefix=CHECK-UBSAN-FUNCTION-TARGET
// RUN: %clang --target=x86_64-sie-ps5 -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-UNDEFINED
-// CHECK-UBSAN-UNDEFINED: "-fsanitize={{((alignment|array-bounds|bool|builtin|enum|float-cast-overflow|integer-divide-by-zero|nonnull-attribute|null|pointer-overflow|return|returns-nonnull-attribute|shift-base|shift-exponent|signed-integer-overflow|unreachable|vla-bound),?){17}"}}
// RUN: not %clang --target=armv6t2-eabi -mexecute-only -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MEXECUTE-ONLY
// RUN: not %clang --target=armv6t2-eabi -mpure-code -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MPURE-CODE
@@ -1060,12 +1059,19 @@
// RUN: not %clang --target=armv6t2-eabi -mpure-code -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-MPURE-CODE
// RUN: %clang --target=armv6t2-eabi -mexecute-only -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-UNDEFINED-VPTR
+// RUN: not %clang --target=aarch64 -mexecute-only -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MEXECUTE-ONLY
+// RUN: not %clang --target=aarch64 -mpure-code -fsanitize=function %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-FUNCTION-MPURE-CODE
+// RUN: not %clang --target=aarch64 -mexecute-only -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-MEXECUTE-ONLY
+// RUN: not %clang --target=aarch64 -mpure-code -fsanitize=kcfi %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-KCFI-MPURE-CODE
+// RUN: %clang --target=aarch64 -mexecute-only -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UBSAN-UNDEFINED
+
// CHECK-UBSAN-KCFI-TARGET-DAG: error: unsupported option '-fsanitize=kcfi' for target 'x86_64-sie-ps5'
// CHECK-UBSAN-KCFI-MEXECUTE-ONLY-DAG: error: invalid argument '-fsanitize=kcfi' not allowed with '-mexecute-only'
// CHECK-UBSAN-KCFI-MPURE-CODE-DAG: error: invalid argument '-fsanitize=kcfi' not allowed with '-mpure-code'
// CHECK-UBSAN-FUNCTION-TARGET-DAG: error: unsupported option '-fsanitize=function' for target 'x86_64-sie-ps5'
// CHECK-UBSAN-FUNCTION-MEXECUTE-ONLY-DAG: error: invalid argument '-fsanitize=function' not allowed with '-mexecute-only'
// CHECK-UBSAN-FUNCTION-MPURE-CODE-DAG: error: invalid argument '-fsanitize=function' not allowed with '-mpure-code'
+// CHECK-UBSAN-UNDEFINED: "-fsanitize={{((alignment|array-bounds|bool|builtin|enum|float-cast-overflow|integer-divide-by-zero|nonnull-attribute|null|pointer-overflow|return|returns-nonnull-attribute|shift-base|shift-exponent|signed-integer-overflow|unreachable|vla-bound),?){17}"}}
// CHECK-UBSAN-UNDEFINED-VPTR: "-fsanitize={{((alignment|array-bounds|bool|builtin|enum|float-cast-overflow|integer-divide-by-zero|nonnull-attribute|null|pointer-overflow|return|returns-nonnull-attribute|shift-base|shift-exponent|signed-integer-overflow|unreachable|vla-bound|vptr),?){18}"}}
// * Test BareMetal toolchain sanitizer support *
diff --git a/llvm/include/llvm/BinaryFormat/ELF.h b/llvm/include/llvm/BinaryFormat/ELF.h
index 8853c4a88b0b593..a5979d029a9eafd 100644
--- a/llvm/include/llvm/BinaryFormat/ELF.h
+++ b/llvm/include/llvm/BinaryFormat/ELF.h
@@ -1300,7 +1300,10 @@ enum : unsigned {
SHF_MIPS_STRING = 0x80000000,
// Make code section unreadable when in execute-only mode
- SHF_ARM_PURECODE = 0x20000000
+ SHF_ARM_PURECODE = 0x20000000,
+
+ // Section contains only program instructions and no program data.
+ SHF_AARCH64_PURECODE = 0x20000000
};
// Section Group Flags
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 3c2c7c8c9fed69a..6cfebca9a4d576e 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -547,7 +547,7 @@ static unsigned getELFSectionType(StringRef Name, SectionKind K) {
return ELF::SHT_PROGBITS;
}
-static unsigned getELFSectionFlags(SectionKind K) {
+static unsigned getELFSectionFlags(SectionKind K, const Triple &T) {
unsigned Flags = 0;
if (!K.isMetadata() && !K.isExclude())
@@ -559,9 +559,12 @@ static unsigned getELFSectionFlags(SectionKind K) {
if (K.isText())
Flags |= ELF::SHF_EXECINSTR;
- if (K.isExecuteOnly())
+ if ((T.isARM() || T.isThumb()) && K.isExecuteOnly())
Flags |= ELF::SHF_ARM_PURECODE;
+ if (T.isAArch64() && K.isExecuteOnly())
+ Flags |= ELF::SHF_AARCH64_PURECODE;
+
if (K.isWriteable())
Flags |= ELF::SHF_WRITE;
@@ -840,7 +843,7 @@ static MCSection *selectExplicitSectionGlobal(const GlobalObject *GO,
// Infer section flags from the section name if we can.
Kind = getELFKindForNamedSection(SectionName, Kind);
- unsigned Flags = getELFSectionFlags(Kind);
+ unsigned Flags = getELFSectionFlags(Kind, TM.getTargetTriple());
auto [Group, IsComdat, ExtraFlags] = getGlobalObjectInfo(GO, TM);
Flags |= ExtraFlags;
@@ -947,7 +950,7 @@ static MCSection *selectELFSectionForGlobal(
MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
- unsigned Flags = getELFSectionFlags(Kind);
+ unsigned Flags = getELFSectionFlags(Kind, TM.getTargetTriple());
// If we have -ffunction-section or -fdata-section then we should emit the
// global value to a uniqued section specifically for it.
@@ -967,7 +970,7 @@ MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
MCSection *TargetLoweringObjectFileELF::getUniqueSectionForFunction(
const Function &F, const TargetMachine &TM) const {
SectionKind Kind = SectionKind::getText();
- unsigned Flags = getELFSectionFlags(Kind);
+ unsigned Flags = getELFSectionFlags(Kind, TM.getTargetTriple());
// If the function's section names is pre-determined via pragma or a
// section attribute, call selectExplicitSectionGlobal.
if (F.hasSection())
diff --git a/llvm/lib/MC/MCParser/ELFAsmParser.cpp b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
index b58210b3c268e99..99b13c68a9966c7 100644
--- a/llvm/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
@@ -328,9 +328,12 @@ static unsigned parseSectionFlags(const Triple &TT, StringRef flagsStr,
flags |= ELF::XCORE_SHF_DP_SECTION;
break;
case 'y':
- if (!(TT.isARM() || TT.isThumb()))
+ if (TT.isARM() || TT.isThumb())
+ flags |= ELF::SHF_ARM_PURECODE;
+ else if (TT.isAArch64())
+ flags |= ELF::SHF_AARCH64_PURECODE;
+ else
return -1U;
- flags |= ELF::SHF_ARM_PURECODE;
break;
case 's':
if (TT.getArch() != Triple::hexagon)
diff --git a/llvm/lib/MC/MCSectionELF.cpp b/llvm/lib/MC/MCSectionELF.cpp
index 25e62b70b5e2a0c..72a959b1c920825 100644
--- a/llvm/lib/MC/MCSectionELF.cpp
+++ b/llvm/lib/MC/MCSectionELF.cpp
@@ -118,6 +118,9 @@ void MCSectionELF::printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
} else if (T.isARM() || T.isThumb()) {
if (Flags & ELF::SHF_ARM_PURECODE)
OS << 'y';
+ } else if (T.isAArch64()) {
+ if (Flags & ELF::SHF_AARCH64_PURECODE)
+ OS << 'y';
} else if (Arch == Triple::hexagon) {
if (Flags & ELF::SHF_HEX_GPREL)
OS << 's';
diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index 539834fc8d4dbfe..05e4d85b2ea5d24 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -803,6 +803,9 @@ void ScalarBitSetTraits<ELFYAML::ELF_SHF>::bitset(IO &IO,
break;
}
switch (Object->getMachine()) {
+ case ELF::EM_AARCH64:
+ BCase(SHF_AARCH64_PURECODE);
+ break;
case ELF::EM_ARM:
BCase(SHF_ARM_PURECODE);
break;
diff --git a/llvm/lib/Target/AArch64/AArch64Features.td b/llvm/lib/Target/AArch64/AArch64Features.td
index 20db70ee38572f2..7c95ba662938d9f 100644
--- a/llvm/lib/Target/AArch64/AArch64Features.td
+++ b/llvm/lib/Target/AArch64/AArch64Features.td
@@ -635,6 +635,11 @@ def FeatureStrictAlign : SubtargetFeature<"strict-align",
"Disallow all unaligned memory "
"access">;
+def FeatureExecuteOnly : SubtargetFeature<"execute-only",
+ "GenExecuteOnly", "true",
+ "Enable the generation of "
+ "execute only code.">;
+
foreach i = {1-7,9-15,18,20-28} in
def FeatureReserveX#i : SubtargetFeature<"reserve-x"#i, "ReserveXRegister["#i#"]", "true",
"Reserve X"#i#", making it unavailable "
diff --git a/llvm/lib/Target/AArch64/AArch64TargetObjectFile.cpp b/llvm/lib/Target/AArch64/AArch64TargetObjectFile.cpp
index 8729fd4b802c8eb..434ae32502d484b 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetObjectFile.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetObjectFile.cpp
@@ -148,3 +148,29 @@ MCSymbol *AArch64_MachoTargetObjectFile::getAuthPtrSlotSymbol(
return getAuthPtrSlotSymbolHelper(getContext(), TM, MMI, MachOMMI, RawSym,
Key, Discriminator);
}
+
+static bool isExecuteOnlyFunction(const GlobalObject *GO, SectionKind Kind,
+ const TargetMachine &TM) {
+ if (const Function *F = dyn_cast<Function>(GO))
+ if (TM.getSubtarget<AArch64Subtarget>(*F).genExecuteOnly() && Kind.isText())
+ return true;
+ return false;
+}
+
+MCSection *AArch64_ELFTargetObjectFile::getExplicitSectionGlobal(
+ const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
+ // Set execute-only access for the explicit section
+ if (isExecuteOnlyFunction(GO, Kind, TM))
+ Kind = SectionKind::getExecuteOnly();
+
+ return TargetLoweringObjectFileELF::getExplicitSectionGlobal(GO, Kind, TM);
+}
+
+MCSection *AArch64_ELFTargetObjectFile::SelectSectionForGlobal(
+ const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
+ // Set execute-only access for the explicit section
+ if (isExecuteOnlyFunction(GO, Kind, TM))
+ Kind = SectionKind::getExecuteOnly();
+
+ return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, Kind, TM);
+}
diff --git a/llvm/lib/Target/AArch64/AArch64TargetObjectFile.h b/llvm/lib/Target/AArch64/AArch64TargetObjectFile.h
index 0c822ac84f200c7..3e9cd51b742a29c 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetObjectFile.h
+++ b/llvm/lib/Target/AArch64/AArch64TargetObjectFile.h
@@ -39,6 +39,12 @@ class AArch64_ELFTargetObjectFile : public TargetLoweringObjectFileELF {
void emitPersonalityValueImpl(MCStreamer &Streamer, const DataLayout &DL,
const MCSymbol *Sym,
const MachineModuleInfo *MMI) const override;
+
+ MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
+ const TargetMachine &TM) const override;
+
+ MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
+ const TargetMachine &TM) const override;
};
/// AArch64_MachoTargetObjectFile - This TLOF implementation is used for Darwin.
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index a6edcf125782b2c..284278e34f8b4d0 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -262,6 +262,10 @@ bool AArch64TTIImpl::isMultiversionedFunction(const Function &F) const {
return F.hasFnAttribute("fmv-features");
}
+const FeatureBitset AArch64TTIImpl::InlineInverseFeatures = {
+ AArch64::FeatureExecuteOnly,
+};
+
bool AArch64TTIImpl::areInlineCompatible(const Function *Caller,
const Function *Callee) const {
SMEAttrs CallerAttrs(*Caller), CalleeAttrs(*Callee);
@@ -284,7 +288,18 @@ bool AArch64TTIImpl::areInlineCompatible(const Function *Caller,
return false;
}
- return BaseT::areInlineCompatible(Caller, Callee);
+ const TargetMachine &TM = getTLI()->getTargetMachine();
+ const FeatureBitset &CallerBits =
+ TM.getSubtargetImpl(*Caller)->getFeatureBits();
+ const FeatureBitset &CalleeBits =
+ TM.getSubtargetImpl(*Callee)->getFeatureBits();
+ // Adjust the feature bitsets by inverting some of the bits. This is needed
+ // for target features that represent restrictions rather than capabilities,
+ // for example "+execute-only".
+ FeatureBitset EffectiveCallerBits = CallerBits ^ InlineInverseFeatures;
+ FeatureBitset EffectiveCalleeBits = CalleeBits ^ InlineInverseFeatures;
+
+ return (EffectiveCallerBits & EffectiveCalleeBits) == EffectiveCalleeBits;
}
bool AArch64TTIImpl::areTypesABICompatible(
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
index b65e3c7a1ab20e5..481cb5511a331b7 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
@@ -48,6 +48,8 @@ class AArch64TTIImpl : public BasicTTIImplBase<AArch64TTIImpl> {
const AArch64Subtarget *ST;
const AArch64TargetLowering *TLI;
+ static const FeatureBitset InlineInverseFeatures;
+
const AArch64Subtarget *getST() const { return ST; }
const AArch64TargetLowering *getTLI() const { return TLI; }
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
index 6b5c5f36cbd4b27..d29d383bc231277 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
@@ -27,6 +27,7 @@
#include "llvm/MC/MCELFStreamer.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
@@ -504,6 +505,23 @@ void AArch64TargetELFStreamer::finish() {
}
}
+ // The mix of execute-only and non-execute-only at link time is
+ // non-execute-only. To avoid the empty implicitly created .text
+ // section from making the whole .text section non-execute-only, we
+ // mark it execute-only if it is empty and there is at least one
+ // execute-only section in the object.
+ if (any_of(Asm, [](const MCSection &Sec) {
+ return cast<MCSectionELF>(Sec).getFlags() & ELF::SHF_AARCH64_PURECODE;
+ })) {
+ auto *Text =
+ static_cast<MCSectionELF *>(Ctx.getObjectFileInfo()->getTextSection());
+ for (auto &F : *Text)
+ if (auto *DF = dyn_cast<MCDataFragment>(&F))
+ if (!DF->getContents().empty())
+ return;
+ Text->setFlags(Text->getFlags() | ELF::SHF_AARCH64_PURECODE);
+ }
+
MCSectionELF *MemtagSec = nullptr;
for (const MCSymbol &Symbol : Asm.symbols()) {
const auto &Sym = cast<MCSymbolELF>(Symbol);
diff --git a/llvm/test/CodeGen/AArch64/execute-only-section.ll b/llvm/test/CodeGen/AArch64/execute-only-section.ll
new file mode 100644
index 000000000000000..15a270b07975e69
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/execute-only-section.ll
@@ -0,0 +1,21 @@
+; RUN: llc -mtriple=aarch64 -mattr=+execute-only %s -o - | FileCheck %s
+
+; CHECK: .section .text,"axy", at progbits,unique,0
+; CHECK-NOT: .section
+; CHECK-NOT: .text
+; CHECK: .globl test_SectionForGlobal
+; CHECK: .type test_SectionForGlobal, at function
+define void @test_SectionForGlobal() {
+entry:
+ ret void
+}
+
+; CHECK: .section .test,"axy", at progbits
+; CHECK-NOT: .section
+; CHECK-NOT: .text
+; CHECK: .globl test_ExplicitSectionForGlobal
+; CHECK: .type test_ExplicitSectionForGlobal, at function
+define void @test_ExplicitSectionForGlobal() section ".test" {
+entry:
+ ret void
+}
diff --git a/llvm/test/MC/ELF/AArch64/execute-only-populated-text-section.s b/llvm/test/MC/ELF/AArch64/execute-only-populated-text-section....
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/125688
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