eugenis created this revision.
Herald added subscribers: hiraditya, kristof.beyls, srhines, aemerson.
Set target_cpu and target_features attributes on __cfi_check_fail and
__cfi_check. Make cfi_check use Thumb encoding on ARM target.
https://reviews.llvm.org/D37656
Files:
clang/lib/CodeGen/CGExpr.cpp
clang/test/CodeGen/cfi-check-thumb.c
llvm/lib/Transforms/IPO/CrossDSOCFI.cpp
llvm/test/Transforms/CrossDSOCFI/thumb.ll
Index: llvm/test/Transforms/CrossDSOCFI/thumb.ll
===================================================================
--- llvm/test/Transforms/CrossDSOCFI/thumb.ll
+++ /dev/null
@@ -1,22 +0,0 @@
-; RUN: opt -mtriple=armv7-linux-android -S -cross-dso-cfi < %s | FileCheck --check-prefix=THUMB %s
-; RUN: opt -mtriple=thumbv7-linux-android -S -cross-dso-cfi < %s | FileCheck --check-prefix=THUMB %s
-; RUN: opt -mtriple=i386-linux -S -cross-dso-cfi < %s | FileCheck --check-prefix=NOTHUMB %s
-; RUN: opt -mtriple=x86_64-linux -S -cross-dso-cfi < %s | FileCheck --check-prefix=NOTHUMB %s
-
-target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
-
-define signext i8 @f() !type !0 !type !1 {
-entry:
- ret i8 1
-}
-
-!llvm.module.flags = !{!2}
-
-!0 = !{i64 0, !"_ZTSFcvE"}
-!1 = !{i64 0, i64 111}
-!2 = !{i32 4, !"Cross-DSO CFI", i32 1}
-
-; THUMB: define void @__cfi_check({{.*}} #[[A:.*]] align 4096
-; THUMB: attributes #[[A]] = { {{.*}}"target-features"="+thumb-mode"
-
-; NOTHUMB: define void @__cfi_check({{.*}} align 4096
Index: llvm/lib/Transforms/IPO/CrossDSOCFI.cpp
===================================================================
--- llvm/lib/Transforms/IPO/CrossDSOCFI.cpp
+++ llvm/lib/Transforms/IPO/CrossDSOCFI.cpp
@@ -117,10 +117,6 @@
F->deleteBody();
F->setAlignment(4096);
- Triple T(M.getTargetTriple());
- if (T.isARM() || T.isThumb())
- F->addFnAttr("target-features", "+thumb-mode");
-
auto args = F->arg_begin();
Value &CallSiteTypeId = *(args++);
CallSiteTypeId.setName("CallSiteTypeId");
Index: clang/test/CodeGen/cfi-check-thumb.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/cfi-check-thumb.c
@@ -0,0 +1,18 @@
+// Test that __cfi_check and __cfi_check_fail have common attributes and calling convention.
+// Also __cfi_check is always using Thumb encoding.
+// RUN: %clang_cc1 -triple arm-unknown-linux -O0 -fsanitize-cfi-cross-dso \
+// RUN: -fsanitize=cfi-vcall \
+// RUN: -emit-llvm -o - %s | FileCheck --check-prefixes=CHECK,CHECK-ARM %s
+//
+// RUN: %clang_cc1 -triple thumb-unknown-linux -O0 -fsanitize-cfi-cross-dso \
+// RUN: -fsanitize=cfi-vcall \
+// RUN: -emit-llvm -o - %s | FileCheck --check-prefixes=CHECK,CHECK-THUMB %s
+//
+// REQUIRES: arm-registered-target
+
+// CHECK-ARM: define weak_odr hidden void @__cfi_check_fail(i8*, i8*) #[[ARM:.*]] {
+// CHECK-THUMB: define weak_odr hidden void @__cfi_check_fail(i8*, i8*) #[[THUMB:.*]] {
+// CHECK: define weak void @__cfi_check(i64, i8*, i8*) #[[THUMB:.*]] {
+
+// CHECK-ARM: attributes #[[ARM]] = {{.*}}"target-features"="{{.*}}-thumb-mode
+// CHECK: attributes #[[THUMB]] = {{.*}}"target-features"="{{.*}}+thumb-mode
Index: clang/lib/CodeGen/CGExpr.cpp
===================================================================
--- clang/lib/CodeGen/CGExpr.cpp
+++ clang/lib/CodeGen/CGExpr.cpp
@@ -2912,6 +2912,33 @@
EmitBlock(Cont);
}
+static void AddTargetAttributes(llvm::AttrBuilder &Builder,
+ CodeGenFunction &CGF, llvm::Function *F,
+ bool ForceThumb) {
+ StringRef TargetCPU = CGF.getTarget().getTargetOpts().CPU;
+ if (TargetCPU != "")
+ Builder.addAttribute("target-cpu", TargetCPU);
+
+ std::vector<std::string> &DefaultFeatures =
+ CGF.getTarget().getTargetOpts().Features;
+ const auto &Triple = CGF.getTarget().getTriple();
+ SmallVector<StringRef, 6> Features;
+ Features.reserve(DefaultFeatures.size() + ForceThumb);
+ if (ForceThumb && (Triple.isARM() || Triple.isThumb())) {
+ for (auto &S : DefaultFeatures)
+ if (S != "-thumb-mode" && S != "+thumb-mode")
+ Features.push_back(S);
+ Features.push_back("+thumb-mode");
+ } else {
+ for (auto &S : DefaultFeatures)
+ Features.push_back(S);
+ }
+
+ std::sort(Features.begin(), Features.end());
+ Builder.addAttribute("target-features",
+ llvm::join(Features.begin(), Features.end(), ","));
+}
+
// Emit a stub for __cfi_check function so that the linker knows about this
// symbol in LTO mode.
void CodeGenFunction::EmitCfiCheckStub() {
@@ -2928,6 +2955,15 @@
llvm::CallInst::Create(
llvm::Intrinsic::getDeclaration(M, llvm::Intrinsic::trap), "", BB);
llvm::ReturnInst::Create(Ctx, nullptr, BB);
+
+ // Set default target-cpu and target-features, but force thumb encoding if
+ // applicable. Note that we don't want the whole set of default function
+ // attributes as SetLLVMFunctionAttributes sets. In particular, __cfi_check
+ // must use the default calling convention for the platform. ABI-changing
+ // flags like -mhard-float should not affect __cfi_check.
+ llvm::AttrBuilder FuncAttrs;
+ AddTargetAttributes(FuncAttrs, *this, F, /*ForceThumb*/ true);
+ F->addAttributes(llvm::AttributeList::FunctionIndex, FuncAttrs);
}
// This function is basically a switch over the CFI failure kind, which is
@@ -3011,6 +3047,11 @@
}
FinishFunction();
+
+ llvm::AttrBuilder FuncAttrs;
+ AddTargetAttributes(FuncAttrs, *this, F, /*ForceThumb*/ false);
+ F->addAttributes(llvm::AttributeList::FunctionIndex, FuncAttrs);
+
// The only reference to this function will be created during LTO link.
// Make sure it survives until then.
CGM.addUsedGlobal(F);
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