[clang] 9e9fa00 - [Arm][AArch64][Clang] Respect function's branch protection attributes. (#101978)
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Fri Aug 9 08:51:43 PDT 2024
Author: Daniel Kiss
Date: 2024-08-09T17:51:38+02:00
New Revision: 9e9fa00dcb9522db3f78d921eda6a18b9ee568bb
URL: https://github.com/llvm/llvm-project/commit/9e9fa00dcb9522db3f78d921eda6a18b9ee568bb
DIFF: https://github.com/llvm/llvm-project/commit/9e9fa00dcb9522db3f78d921eda6a18b9ee568bb.diff
LOG: [Arm][AArch64][Clang] Respect function's branch protection attributes. (#101978)
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.
Added:
Modified:
clang/lib/CodeGen/CGCall.cpp
clang/lib/CodeGen/TargetInfo.cpp
clang/lib/CodeGen/TargetInfo.h
clang/test/CodeGen/aarch64-branch-protection-attr.c
clang/test/CodeGen/arm-branch-protection-attr-1.c
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 070001a180ab8..e4f221ae55eef 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -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
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 38faa50cf19cf..64a9a5554caf7 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -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
diff erent.
+ 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());
diff --git a/clang/lib/CodeGen/TargetInfo.h b/clang/lib/CodeGen/TargetInfo.h
index f38275c51d582..0244ca006d498 100644
--- a/clang/lib/CodeGen/TargetInfo.h
+++ b/clang/lib/CodeGen/TargetInfo.h
@@ -423,13 +423,16 @@ class TargetCodeGenInfo {
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);
diff --git a/clang/test/CodeGen/aarch64-branch-protection-attr.c b/clang/test/CodeGen/aarch64-branch-protection-attr.c
index e7ae7fb1570c9..c66bce1bee6d3 100644
--- a/clang/test/CodeGen/aarch64-branch-protection-attr.c
+++ b/clang/test/CodeGen/aarch64-branch-protection-attr.c
@@ -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"
diff --git a/clang/test/CodeGen/arm-branch-protection-attr-1.c b/clang/test/CodeGen/arm-branch-protection-attr-1.c
index dd38cf347f04f..5ca6a1a4d13b4 100644
--- a/clang/test/CodeGen/arm-branch-protection-attr-1.c
+++ b/clang/test/CodeGen/arm-branch-protection-attr-1.c
@@ -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:]]
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