I have attached a combined patch for 3.0 of the changes that went on trunk.
Cheers,
Rafael
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 924ec84..275045c 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -29,6 +29,7 @@
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Mangle.h"
#include "clang/AST/RecordLayout.h"
+#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
@@ -858,6 +859,59 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
}
}
+namespace {
+ struct FunctionIsDirectlyRecursive :
+ public RecursiveASTVisitor<FunctionIsDirectlyRecursive> {
+ const StringRef Name;
+ bool Result;
+ FunctionIsDirectlyRecursive(const FunctionDecl *F) :
+ Name(F->getName()), Result(false) {
+ }
+ typedef RecursiveASTVisitor<FunctionIsDirectlyRecursive> Base;
+
+ bool TraverseCallExpr(CallExpr *E) {
+ const Decl *D = E->getCalleeDecl();
+ if (!D)
+ return true;
+ AsmLabelAttr *Attr = D->getAttr<AsmLabelAttr>();
+ if (!Attr)
+ return true;
+ if (Name == Attr->getLabel()) {
+ Result = true;
+ return false;
+ }
+ return true;
+ }
+ };
+}
+
+// isTriviallyRecursiveViaAsm - Check if this function calls another
+// decl that, because of the asm attribute, ends up pointing to itself.
+bool
+CodeGenModule::isTriviallyRecursiveViaAsm(const FunctionDecl *F) {
+ if (getCXXABI().getMangleContext().shouldMangleDeclName(F))
+ return false;
+
+ FunctionIsDirectlyRecursive Walker(F);
+ Walker.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));
+ return Walker.Result;
+}
+
+bool
+CodeGenModule::shouldEmitFunction(const FunctionDecl *F) {
+ if (getFunctionLinkage(F) != llvm::Function::AvailableExternallyLinkage)
+ return true;
+ if (CodeGenOpts.OptimizationLevel == 0 &&
+ !F->hasAttr<AlwaysInlineAttr>())
+ return false;
+ // PR9614. Avoid cases where the source code is lying to us. An available
+ // externally function should have an equivalent function somewhere else,
+ // but a function that calls itself is clearly not equivalent to the real
+ // implementation.
+ // This happens in glibc's btowc and in some configure checks.
+ return !isTriviallyRecursiveViaAsm(F);
+}
+
void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
@@ -868,10 +922,7 @@ void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
// At -O0, don't generate IR for functions with available_externally
// linkage.
- if (CodeGenOpts.OptimizationLevel == 0 &&
- !Function->hasAttr<AlwaysInlineAttr>() &&
- getFunctionLinkage(Function)
- ==
llvm::Function::AvailableExternallyLinkage)
+ if (!shouldEmitFunction(Function))
return;
if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 8e38a89..dbc6a87 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -324,6 +324,8 @@ class CodeGenModule : public CodeGenTypeCache {
void createOpenCLRuntime();
void createCUDARuntime();
+ bool isTriviallyRecursiveViaAsm(const FunctionDecl *F);
+ bool shouldEmitFunction(const FunctionDecl *F);
llvm::LLVMContext &VMContext;
/// @name Cache for Blocks Runtime Globals
diff --git a/test/CodeGen/pr9614.c b/test/CodeGen/pr9614.c
new file mode 100644
index 0000000..8c76776
--- /dev/null
+++ b/test/CodeGen/pr9614.c
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -emit-llvm %s -O1 -o - | FileCheck %s
+
+extern void foo_alias (void) __asm ("foo");
+inline void foo (void) {
+ return foo_alias ();
+}
+extern void bar_alias (void) __asm ("bar");
+inline __attribute__ ((__always_inline__)) void bar (void) {
+ return bar_alias ();
+}
+void f(void) {
+ foo();
+ bar();
+}
+
+// CHECK: define void @f()
+// CHECK: call void @foo()
+// CHECK-NEXT: call void @bar()
+// CHECK-NEXT: ret void
+
+// CHECK: declare void @foo()
+// CHECK: declare void @bar()
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