[clang] [llvm] [clang][AArch64] Add a -mbranch-protection option to enable GCS (PR #75486)
John Brawn via cfe-commits
cfe-commits at lists.llvm.org
Tue Jan 2 08:14:15 PST 2024
https://github.com/john-brawn-arm updated https://github.com/llvm/llvm-project/pull/75486
>From cceb8766d2c93cadc940b45f0817abc5e6d0a225 Mon Sep 17 00:00:00 2001
From: John Brawn <john.brawn at arm.com>
Date: Wed, 13 Dec 2023 16:20:33 +0000
Subject: [PATCH] [clang][AArch64] Add a -mbranch-protection option to enable
GCS
-mbranch-protection=gcs (enabled by -mbranch-protection=standard)
causes generated objects to be marked with the gcs feature. This is
done via the guarded-control-stack module flag, in a similar way to
branch-target-enforcement and sign-return-address.
Enabling GCS causes the GNU_PROPERTY_AARCH64_FEATURE_1_GCS bit to be
set on generated objects. No code generation changes are required, as
GCS just requires that functions are called using BL and returned from
using RET (or other similar variant instructions), which is already
the case.
---
clang/include/clang/Basic/LangOptions.def | 1 +
clang/include/clang/Basic/TargetInfo.h | 1 +
clang/include/clang/Driver/Options.td | 2 ++
clang/lib/Basic/Targets/AArch64.cpp | 7 +++++
clang/lib/CodeGen/CodeGenModule.cpp | 2 ++
clang/lib/CodeGen/Targets/AArch64.cpp | 2 ++
clang/lib/Driver/ToolChains/Clang.cpp | 6 +++-
.../CodeGen/aarch64-branch-protection-attr.c | 28 +++++++++++--------
clang/test/CodeGen/aarch64-targetattr.c | 2 +-
clang/test/Driver/aarch64-security-options.c | 11 +++++---
.../Preprocessor/aarch64-target-features.c | 15 ++++++++++
.../llvm/TargetParser/ARMTargetParserCommon.h | 1 +
llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp | 5 ++++
.../TargetParser/ARMTargetParserCommon.cpp | 5 ++++
.../CodeGen/AArch64/note-gnu-property-gcs.ll | 20 +++++++++++++
15 files changed, 90 insertions(+), 18 deletions(-)
create mode 100644 llvm/test/CodeGen/AArch64/note-gnu-property-gcs.ll
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index 21abc346cf17ac..0428b70c602062 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -457,6 +457,7 @@ ENUM_LANGOPT(SignReturnAddressKey, SignReturnAddressKeyKind, 1, SignReturnAddres
"Key used for return address signing")
LANGOPT(BranchTargetEnforcement, 1, 0, "Branch-target enforcement enabled")
LANGOPT(BranchProtectionPAuthLR, 1, 0, "Use PC as a diversifier using PAuthLR NOP instructions.")
+LANGOPT(GuardedControlStack, 1, 0, "Guarded control stack enabled")
LANGOPT(SpeculativeLoadHardening, 1, 0, "Speculative load hardening enabled")
diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
index ac3c324c6c29c4..3eb23ebdacf0ed 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -1373,6 +1373,7 @@ class TargetInfo : public TransferrableTargetInfo,
LangOptions::SignReturnAddressKeyKind::AKey;
bool BranchTargetEnforcement = false;
bool BranchProtectionPAuthLR = false;
+ bool GuardedControlStack = false;
};
/// Determine if the Architecture in this TargetInfo supports branch
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 2b93ddf033499c..457e4e7a7e0c33 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -7002,6 +7002,8 @@ def mbranch_target_enforce : Flag<["-"], "mbranch-target-enforce">,
MarshallingInfoFlag<LangOpts<"BranchTargetEnforcement">>;
def mbranch_protection_pauth_lr : Flag<["-"], "mbranch-protection-pauth-lr">,
MarshallingInfoFlag<LangOpts<"BranchProtectionPAuthLR">>;
+def mguarded_control_stack : Flag<["-"], "mguarded-control-stack">,
+ MarshallingInfoFlag<LangOpts<"GuardedControlStack">>;
def fno_dllexport_inlines : Flag<["-"], "fno-dllexport-inlines">,
MarshallingInfoNegativeFlag<LangOpts<"DllExportInlines">>;
def cfguard_no_checks : Flag<["-"], "cfguard-no-checks">,
diff --git a/clang/lib/Basic/Targets/AArch64.cpp b/clang/lib/Basic/Targets/AArch64.cpp
index 2f8395cb8932f2..9ebaf4d40cd7e5 100644
--- a/clang/lib/Basic/Targets/AArch64.cpp
+++ b/clang/lib/Basic/Targets/AArch64.cpp
@@ -226,6 +226,7 @@ bool AArch64TargetInfo::validateBranchProtection(StringRef Spec, StringRef,
BPI.BranchTargetEnforcement = PBP.BranchTargetEnforcement;
BPI.BranchProtectionPAuthLR = PBP.BranchProtectionPAuthLR;
+ BPI.GuardedControlStack = PBP.GuardedControlStack;
return true;
}
@@ -532,6 +533,9 @@ void AArch64TargetInfo::getTargetDefines(const LangOptions &Opts,
if (Opts.BranchTargetEnforcement)
Builder.defineMacro("__ARM_FEATURE_BTI_DEFAULT", "1");
+ if (Opts.GuardedControlStack)
+ Builder.defineMacro("__ARM_FEATURE_GCS_DEFAULT", "1");
+
if (HasLS64)
Builder.defineMacro("__ARM_FEATURE_LS64", "1");
@@ -544,6 +548,9 @@ void AArch64TargetInfo::getTargetDefines(const LangOptions &Opts,
if (HasD128)
Builder.defineMacro("__ARM_FEATURE_SYSREG128", "1");
+ if (HasGCS)
+ Builder.defineMacro("__ARM_FEATURE_GCS", "1");
+
if (*ArchInfo == llvm::AArch64::ARMV8_1A)
getTargetDefinesARMV81A(Opts, Builder);
else if (*ArchInfo == llvm::AArch64::ARMV8_2A)
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index d78f2594a23764..dfe0e70426e4d5 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1109,6 +1109,8 @@ void CodeGenModule::Release() {
if (LangOpts.BranchProtectionPAuthLR)
getModule().addModuleFlag(llvm::Module::Min, "branch-protection-pauth-lr",
1);
+ if (LangOpts.GuardedControlStack)
+ getModule().addModuleFlag(llvm::Module::Min, "guarded-control-stack", 1);
if (LangOpts.hasSignReturnAddress())
getModule().addModuleFlag(llvm::Module::Min, "sign-return-address", 1);
if (LangOpts.isSignReturnAddressScopeAll())
diff --git a/clang/lib/CodeGen/Targets/AArch64.cpp b/clang/lib/CodeGen/Targets/AArch64.cpp
index 7102d190fe008b..ee7f95084d2e0b 100644
--- a/clang/lib/CodeGen/Targets/AArch64.cpp
+++ b/clang/lib/CodeGen/Targets/AArch64.cpp
@@ -138,6 +138,8 @@ class AArch64TargetCodeGenInfo : public TargetCodeGenInfo {
BPI.BranchTargetEnforcement ? "true" : "false");
Fn->addFnAttr("branch-protection-pauth-lr",
BPI.BranchProtectionPAuthLR ? "true" : "false");
+ Fn->addFnAttr("guarded-control-stack",
+ BPI.GuardedControlStack ? "true" : "false");
}
bool isScalarizableAsmOperand(CodeGen::CodeGenFunction &CGF,
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index acfa119805068d..2457f22e17bd7b 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -1497,7 +1497,7 @@ static void CollectARMPACBTIOptions(const ToolChain &TC, const ArgList &Args,
<< Triple.getArchName();
StringRef Scope, Key;
- bool IndirectBranches, BranchProtectionPAuthLR;
+ bool IndirectBranches, BranchProtectionPAuthLR, GuardedControlStack;
if (A->getOption().matches(options::OPT_msign_return_address_EQ)) {
Scope = A->getValue();
@@ -1507,6 +1507,7 @@ static void CollectARMPACBTIOptions(const ToolChain &TC, const ArgList &Args,
Key = "a_key";
IndirectBranches = false;
BranchProtectionPAuthLR = false;
+ GuardedControlStack = false;
} else {
StringRef DiagMsg;
llvm::ARM::ParsedBranchProtection PBP;
@@ -1520,6 +1521,7 @@ static void CollectARMPACBTIOptions(const ToolChain &TC, const ArgList &Args,
Key = PBP.Key;
BranchProtectionPAuthLR = PBP.BranchProtectionPAuthLR;
IndirectBranches = PBP.BranchTargetEnforcement;
+ GuardedControlStack = PBP.GuardedControlStack;
}
CmdArgs.push_back(
@@ -1532,6 +1534,8 @@ static void CollectARMPACBTIOptions(const ToolChain &TC, const ArgList &Args,
Args.MakeArgString(Twine("-mbranch-protection-pauth-lr")));
if (IndirectBranches)
CmdArgs.push_back("-mbranch-target-enforce");
+ if (GuardedControlStack)
+ CmdArgs.push_back("-mguarded-control-stack");
}
void Clang::AddARMTargetArgs(const llvm::Triple &Triple, const ArgList &Args,
diff --git a/clang/test/CodeGen/aarch64-branch-protection-attr.c b/clang/test/CodeGen/aarch64-branch-protection-attr.c
index 8ab3e17ade4264..f0e1dcccd1e827 100644
--- a/clang/test/CodeGen/aarch64-branch-protection-attr.c
+++ b/clang/test/CodeGen/aarch64-branch-protection-attr.c
@@ -63,29 +63,33 @@ __attribute__ ((target("branch-protection=pac-ret+pc+bti")))
void pauthlr_bti() {}
// CHECK: define{{.*}} void @pauthlr_bti() #[[#PAUTHLR_BTI:]]
+__attribute__ ((target("branch-protection=gcs")))
+void gcs() {}
+// CHECK: define{{.*}} void @gcs() #[[#GCS:]]
-// CHECK-DAG: attributes #[[#NONE]] = { {{.*}} "branch-target-enforcement"="false" {{.*}} "sign-return-address"="none"
+// CHECK-DAG: attributes #[[#NONE]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="none"
-// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement"="true" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#STD]] = { {{.*}} "branch-target-enforcement"="true" "guarded-control-stack"="true" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
-// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"="true" {{.*}} "sign-return-address"="none"
+// CHECK-DAG: attributes #[[#BTI]] = { {{.*}} "branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}} "sign-return-address"="none"
-// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "branch-target-enforcement"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAC]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
-// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "branch-target-enforcement"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PACLEAF]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
-// CHECK-DAG: attributes #[[#PACBKEY]] = { {{.*}}"branch-target-enforcement"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
+// CHECK-DAG: attributes #[[#PACBKEY]] = { {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}} "sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
-// CHECK-DAG: attributes #[[#PACBKEYLEAF]] = { {{.*}} "branch-target-enforcement"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="b_key"
+// CHECK-DAG: attributes #[[#PACBKEYLEAF]] = { {{.*}} "branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="b_key"
-// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}}"branch-target-enforcement"="true" {{.*}} "sign-return-address"="all" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}}"branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}} "sign-return-address"="all" "sign-return-address-key"="a_key"
-// CHECK-DAG: attributes #[[#PAUTHLR]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAUTHLR]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
-// CHECK-DAG: attributes #[[#PAUTHLR_BKEY]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
+// CHECK-DAG: attributes #[[#PAUTHLR_BKEY]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="b_key"
-// CHECK-DAG: attributes #[[#PAUTHLR_LEAF]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAUTHLR_LEAF]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="false" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
-// CHECK-DAG: attributes #[[#PAUTHLR_BTI]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="true" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#PAUTHLR_BTI]] = { {{.*}}"branch-protection-pauth-lr"="true" {{.*}}"branch-target-enforcement"="true" "guarded-control-stack"="false" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
+// CHECK-DAG: attributes #[[#GCS]] = { {{.*}}"branch-target-enforcement"="false" "guarded-control-stack"="true" {{.*}} "sign-return-address"="none"
diff --git a/clang/test/CodeGen/aarch64-targetattr.c b/clang/test/CodeGen/aarch64-targetattr.c
index 9664b723a2b2cd..5f557532a4b4a7 100644
--- a/clang/test/CodeGen/aarch64-targetattr.c
+++ b/clang/test/CodeGen/aarch64-targetattr.c
@@ -110,6 +110,6 @@ void minusarch() {}
// CHECK: attributes #13 = { {{.*}} "target-features"="+fp-armv8,+fullfp16,+neon,+sve,-sve2" }
// CHECK: attributes #14 = { {{.*}} "target-features"="+fullfp16" }
// CHECK: attributes #15 = { {{.*}} "target-cpu"="neoverse-n1" "target-features"="+aes,+bf16,+crc,+dotprod,+fp-armv8,+fullfp16,+i8mm,+lse,+neon,+ras,+rcpc,+rdm,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a" "tune-cpu"="cortex-a710" }
-// CHECK: attributes #16 = { {{.*}} "branch-target-enforcement"="true" {{.*}} "target-features"="+aes,+bf16,+crc,+dotprod,+fp-armv8,+fullfp16,+i8mm,+lse,+neon,+ras,+rcpc,+rdm,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a" "tune-cpu"="cortex-a710" }
+// CHECK: attributes #16 = { {{.*}} "branch-target-enforcement"="true" "guarded-control-stack"="true" {{.*}} "target-features"="+aes,+bf16,+crc,+dotprod,+fp-armv8,+fullfp16,+i8mm,+lse,+neon,+ras,+rcpc,+rdm,+sha2,+spe,+ssbs,+sve,+sve2,+v8.1a,+v8.2a,+v8.3a,+v8.4a,+v8.5a,+v8.6a,+v8a" "tune-cpu"="cortex-a710" }
// CHECK: attributes #17 = { {{.*}} "target-features"="-neon" }
// CHECK: attributes #18 = { {{.*}} "target-features"="-v9.3a" }
diff --git a/clang/test/Driver/aarch64-security-options.c b/clang/test/Driver/aarch64-security-options.c
index e1f3013c411372..146add2d1cf704 100644
--- a/clang/test/Driver/aarch64-security-options.c
+++ b/clang/test/Driver/aarch64-security-options.c
@@ -1,17 +1,17 @@
// Check the -msign-return-address= option, which has a required argument to
// select scope.
// RUN: %clang --target=aarch64 -c %s -### -msign-return-address=none 2>&1 | \
-// RUN: FileCheck %s --check-prefix=RA-OFF --check-prefix=KEY --check-prefix=BTE-OFF --check-prefix=WARN
+// RUN: FileCheck %s --check-prefix=RA-OFF --check-prefix=KEY --check-prefix=BTE-OFF --check-prefix=GCS-OFF --check-prefix=WARN
// RUN: %clang --target=aarch64 -c %s -### -msign-return-address=non-leaf 2>&1 | \
-// RUN: FileCheck %s --check-prefix=RA-NON-LEAF --check-prefix=KEY-A --check-prefix=BTE-OFF --check-prefix=WARN
+// RUN: FileCheck %s --check-prefix=RA-NON-LEAF --check-prefix=KEY-A --check-prefix=BTE-OFF --check-prefix=GCS-OFF --check-prefix=WARN
// RUN: %clang --target=aarch64 -c %s -### -msign-return-address=all 2>&1 | \
-// RUN: FileCheck %s --check-prefix=RA-ALL --check-prefix=KEY-A --check-prefix=BTE-OFF --check-prefix=WARN
+// RUN: FileCheck %s --check-prefix=RA-ALL --check-prefix=KEY-A --check-prefix=BTE-OFF --check-prefix=GCS-OFF --check-prefix=WARN
// -mbranch-protection with standard
// RUN: %clang --target=aarch64 -c %s -### -mbranch-protection=standard 2>&1 | \
-// RUN: FileCheck %s --check-prefix=RA-NON-LEAF --check-prefix=KEY-A --check-prefix=BTE-ON --check-prefix=WARN
+// RUN: FileCheck %s --check-prefix=RA-NON-LEAF --check-prefix=KEY-A --check-prefix=BTE-ON --check-prefix=GCS-ON --check-prefix=WARN
// If the -msign-return-address and -mbranch-protection are both used, the
// right-most one controls return address signing.
@@ -42,6 +42,9 @@
// BTE-OFF-NOT: "-mbranch-target-enforce"
// BTE-ON: "-mbranch-target-enforce"
+// GCS-OFF-NOT: "-mguarded-control-stack"
+// GCS-ON: "-mguarded-control-stack"
+
// CONFLICT: "-msign-return-address=none"
// BAD-RA-PROTECTION: unsupported argument 'foo' to option '-msign-return-address='
diff --git a/clang/test/Preprocessor/aarch64-target-features.c b/clang/test/Preprocessor/aarch64-target-features.c
index b3da54162da04b..6c5c2ad0b602d8 100644
--- a/clang/test/Preprocessor/aarch64-target-features.c
+++ b/clang/test/Preprocessor/aarch64-target-features.c
@@ -49,6 +49,7 @@
// CHECK-NOT: __ARM_FEATURE_DOTPROD
// CHECK-NOT: __ARM_FEATURE_PAC_DEFAULT
// CHECK-NOT: __ARM_FEATURE_BTI_DEFAULT
+// CHECK-NOT: __ARM_FEATURE_GCS_DEFAULT
// CHECK-NOT: __ARM_BF16_FORMAT_ALTERNATIVE 1
// CHECK-NOT: __ARM_FEATURE_BF16 1
// CHECK-NOT: __ARM_FEATURE_BF16_VECTOR_ARITHMETIC 1
@@ -587,6 +588,20 @@
// CHECK-SYS128: __ARM_FEATURE_SYSREG128 1
// CHECK-NOSYS128-NOT: __ARM_FEATURE_SYSREG128 1
+// ================== Check Armv8.9-A/Armv9.4-A Guarded Control Stack (FEAT_GCS)
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv8.9-a -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-NOGCS,CHECK-NOGCS-DEFAULT %s
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv9.4-a -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-NOGCS,CHECK-NOGCS-DEFAULT %s
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv8.9-a+gcs -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-GCS,CHECK-NOGCS-DEFAULT %s
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv9.4-a+gcs -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-GCS,CHECK-NOGCS-DEFAULT %s
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv8.9-a -mbranch-protection=gcs -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-NOGCS,CHECK-GCS-DEFAULT %s
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv9.4-a -mbranch-protection=gcs -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-NOGCS,CHECK-GCS-DEFAULT %s
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv8.9-a+gcs -mbranch-protection=gcs -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-GCS,CHECK-GCS-DEFAULT %s
+// RUN: %clang -target aarch64-arm-none-eabi -march=armv9.4-a+gcs -mbranch-protection=gcs -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-GCS,CHECK-GCS-DEFAULT %s
+// CHECK-GCS: __ARM_FEATURE_GCS 1
+// CHECK-NOGCS-NOT: __ARM_FEATURE_GCS 1
+// CHECK-GCS-DEFAULT: __ARM_FEATURE_GCS_DEFAULT 1
+// CHECK-NOGCS-DEFAULT-NOT: __ARM_FEATURE_GCS_DEFAULT 1
+
// ================== Check default macros for Armv8.1-A and later
// RUN: %clang -target aarch64-none-elf -march=armv8.1-a -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-V81-OR-LATER,CHECK-BEFORE-V83,CHECK-BEFORE-V85 %s
// RUN: %clang -target aarch64-none-elf -march=armv8.2-a -x c -E -dM %s -o - | FileCheck --check-prefixes=CHECK-V81-OR-LATER,CHECK-BEFORE-V83,CHECK-BEFORE-V85 %s
diff --git a/llvm/include/llvm/TargetParser/ARMTargetParserCommon.h b/llvm/include/llvm/TargetParser/ARMTargetParserCommon.h
index 1e4187c6fb111e..8ae553ca80ddc3 100644
--- a/llvm/include/llvm/TargetParser/ARMTargetParserCommon.h
+++ b/llvm/include/llvm/TargetParser/ARMTargetParserCommon.h
@@ -42,6 +42,7 @@ struct ParsedBranchProtection {
StringRef Key;
bool BranchTargetEnforcement;
bool BranchProtectionPAuthLR;
+ bool GuardedControlStack;
};
bool parseBranchProtection(StringRef Spec, ParsedBranchProtection &PBP,
diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index 90e1ce9ddf66b0..7d2ff146a340bd 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -256,6 +256,11 @@ void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
if (BTE->getZExtValue())
Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
+ if (const auto *GCS = mdconst::extract_or_null<ConstantInt>(
+ M.getModuleFlag("guarded-control-stack")))
+ if (GCS->getZExtValue())
+ Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_GCS;
+
if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("sign-return-address")))
if (Sign->getZExtValue())
diff --git a/llvm/lib/TargetParser/ARMTargetParserCommon.cpp b/llvm/lib/TargetParser/ARMTargetParserCommon.cpp
index 6d3a59d532fd3d..9ce6c502016ee2 100644
--- a/llvm/lib/TargetParser/ARMTargetParserCommon.cpp
+++ b/llvm/lib/TargetParser/ARMTargetParserCommon.cpp
@@ -147,6 +147,7 @@ bool ARM::parseBranchProtection(StringRef Spec, ParsedBranchProtection &PBP,
if (Spec == "standard") {
PBP.Scope = "non-leaf";
PBP.BranchTargetEnforcement = true;
+ PBP.GuardedControlStack = true;
return true;
}
@@ -173,6 +174,10 @@ bool ARM::parseBranchProtection(StringRef Spec, ParsedBranchProtection &PBP,
}
continue;
}
+ if (Opt == "gcs") {
+ PBP.GuardedControlStack = true;
+ continue;
+ }
if (Opt == "")
Err = "<empty>";
else
diff --git a/llvm/test/CodeGen/AArch64/note-gnu-property-gcs.ll b/llvm/test/CodeGen/AArch64/note-gnu-property-gcs.ll
new file mode 100644
index 00000000000000..7dbb7c4ec9008b
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/note-gnu-property-gcs.ll
@@ -0,0 +1,20 @@
+; RUN: llc -mtriple=aarch64-linux %s -o - | \
+; RUN: FileCheck %s --check-prefix=ASM
+; RUN: llc -mtriple=aarch64-linux %s -filetype=obj -o - | \
+; RUN: llvm-readelf --notes - | FileCheck %s --check-prefix=OBJ
+
+define dso_local i32 @f() {
+entry:
+ ret i32 0
+}
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 8, !"guarded-control-stack", i32 1}
+
+; GCS attribute present
+; ASM: .word 3221225472
+; ASM-NEXT: .word 4
+; ASM-NEXT: .word 4
+
+; OBJ: Properties: aarch64 feature: GCS
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