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[Arm][AArch64][Clang] Respect function's branch protection attributes. (#101978)

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Default attributes assigned to all functions according to the command
line parameters. Some functions might have their own attributes and we
need to set or remove attributes accordingly.
Tests are updated to test this scenarios too.
This commit is contained in:
Daniel Kiss
2024-08-09 17:51:38 +02:00
committed by GitHub
parent 7a98071da2
commit 9e9fa00dcb
5 changed files with 52 additions and 8 deletions
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2
clang/lib/CodeGen/CGCall.cpp
View File

@@ -2010,7 +2010,7 @@ static void getTrivialDefaultFunctionAttributes(
}
TargetInfo::BranchProtectionInfo BPI(LangOpts);
TargetCodeGenInfo::setBranchProtectionFnAttributes(BPI, FuncAttrs);
TargetCodeGenInfo::initBranchProtectionFnAttributes(BPI, FuncAttrs);
}
/// Merges `target-features` from \TargetOpts and \F, and sets the result in

32
clang/lib/CodeGen/TargetInfo.cpp
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@@ -209,13 +209,37 @@ llvm::Value *TargetCodeGenInfo::createEnqueuedBlockKernel(
void TargetCodeGenInfo::setBranchProtectionFnAttributes(
const TargetInfo::BranchProtectionInfo &BPI, llvm::Function &F) {
llvm::AttrBuilder FuncAttrs(F.getContext());
setBranchProtectionFnAttributes(BPI, FuncAttrs);
F.addFnAttrs(FuncAttrs);
// Called on already created and initialized function where attributes already
// set from command line attributes but some might need to be removed as the
// actual BPI is different.
if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
F.addFnAttr("sign-return-address", BPI.getSignReturnAddrStr());
F.addFnAttr("sign-return-address-key", BPI.getSignKeyStr());
} else {
if (F.hasFnAttribute("sign-return-address"))
F.removeFnAttr("sign-return-address");
if (F.hasFnAttribute("sign-return-address-key"))
F.removeFnAttr("sign-return-address-key");
}
auto AddRemoveAttributeAsSet = [&](bool Set, const StringRef &ModAttr) {
if (Set)
F.addFnAttr(ModAttr);
else if (F.hasFnAttribute(ModAttr))
F.removeFnAttr(ModAttr);
};
AddRemoveAttributeAsSet(BPI.BranchTargetEnforcement,
"branch-target-enforcement");
AddRemoveAttributeAsSet(BPI.BranchProtectionPAuthLR,
"branch-protection-pauth-lr");
AddRemoveAttributeAsSet(BPI.GuardedControlStack, "guarded-control-stack");
}
void TargetCodeGenInfo::setBranchProtectionFnAttributes(
void TargetCodeGenInfo::initBranchProtectionFnAttributes(
const TargetInfo::BranchProtectionInfo &BPI, llvm::AttrBuilder &FuncAttrs) {
// Only used for initializing attributes in the AttrBuilder, which will not
// contain any of these attributes so no need to remove anything.
if (BPI.SignReturnAddr != LangOptions::SignReturnAddressScopeKind::None) {
FuncAttrs.addAttribute("sign-return-address", BPI.getSignReturnAddrStr());
FuncAttrs.addAttribute("sign-return-address-key", BPI.getSignKeyStr());

7
clang/lib/CodeGen/TargetInfo.h
View File

@@ -423,13 +423,16 @@ public:
return nullptr;
}
// Set the Branch Protection Attributes of the Function accordingly to the
// BPI. Remove attributes that contradict with current BPI.
static void
setBranchProtectionFnAttributes(const TargetInfo::BranchProtectionInfo &BPI,
llvm::Function &F);
// Add the Branch Protection Attributes of the FuncAttrs.
static void
setBranchProtectionFnAttributes(const TargetInfo::BranchProtectionInfo &BPI,
llvm::AttrBuilder &FuncAttrs);
initBranchProtectionFnAttributes(const TargetInfo::BranchProtectionInfo &BPI,
llvm::AttrBuilder &FuncAttrs);
protected:
static std::string qualifyWindowsLibrary(StringRef Lib);

13
clang/test/CodeGen/aarch64-branch-protection-attr.c
View File

@@ -1,6 +1,18 @@
// REQUIRES: aarch64-registered-target
// RUN: %clang_cc1 -triple aarch64 -emit-llvm -target-cpu generic -target-feature +v8.5a %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple aarch64 -emit-llvm -target-cpu generic -target-feature +v8.5a -mbranch-target-enforce %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple aarch64 -emit-llvm -target-cpu generic -target-feature +v8.5a -mguarded-control-stack %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple aarch64 -emit-llvm -target-cpu generic -target-feature +v8.5a -msign-return-address=non-leaf -msign-return-address-key=a_key %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple aarch64 -emit-llvm -target-cpu generic -target-feature +v8.5a -msign-return-address=all -msign-return-address-key=b_key %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple aarch64 -emit-llvm -target-cpu generic -target-feature +v8.5a -mbranch-protection-pauth-lr -msign-return-address=all -msign-return-address-key=a_key %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple aarch64 -emit-llvm -target-cpu generic -target-feature +v8.5a -mguarded-control-stack -mbranch-target-enforce -mbranch-protection-pauth-lr -msign-return-address=all -msign-return-address-key=a_key %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
__attribute__ ((target("branch-protection=none")))
void none() {}
@@ -83,7 +95,6 @@ void gcs() {}
// CHECK-DAG: attributes #[[#BTIPACLEAF]] = { {{.*}} "branch-target-enforcement" {{.*}}"sign-return-address"="all" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#PAUTHLR]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="a_key"
// CHECK-DAG: attributes #[[#PAUTHLR_BKEY]] = { {{.*}} "branch-protection-pauth-lr" {{.*}}"sign-return-address"="non-leaf" "sign-return-address-key"="b_key"

6
clang/test/CodeGen/arm-branch-protection-attr-1.c
View File

@@ -1,6 +1,12 @@
// REQUIRES: arm-registered-target
// RUN: %clang_cc1 -triple thumbv7m-unknown-unknown-eabi -emit-llvm %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple thumbv7m-unknown-unknown-eabi -mbranch-target-enforce -emit-llvm %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple thumbv7m-unknown-unknown-eabi -msign-return-address=all -emit-llvm %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -triple thumbv7m-unknown-unknown-eabi -mbranch-target-enforce -msign-return-address=all -emit-llvm %s -o - \
// RUN: | FileCheck %s --check-prefix=CHECK
__attribute__((target("branch-protection=none"))) void none() {}
// CHECK: define{{.*}} void @none() #[[#NONE:]]