Fix pr9614 by not emitting an available_externally function when it calls
itself via an asm label. available_externally functions are supposed to correspond to an external function, and that is not the case in the examples in pr9614. llvm-svn: 143049
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@ -29,6 +29,7 @@
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#include "clang/AST/DeclTemplate.h"
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#include "clang/AST/Mangle.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/AST/RecursiveASTVisitor.h"
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#include "clang/Basic/Diagnostic.h"
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#include "clang/Basic/SourceManager.h"
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#include "clang/Basic/TargetInfo.h"
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@ -858,6 +859,62 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
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}
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}
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namespace {
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struct FunctionIsDirectlyRecursive :
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public RecursiveASTVisitor<FunctionIsDirectlyRecursive> {
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const StringRef Name;
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bool Result;
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FunctionIsDirectlyRecursive(const FunctionDecl *F) :
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Name(F->getName()), Result(false) {
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}
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typedef RecursiveASTVisitor<FunctionIsDirectlyRecursive> Base;
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bool TraverseCallExpr(CallExpr *E) {
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const Decl *D = E->getCalleeDecl();
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if (!D)
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return true;
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AsmLabelAttr *Attr = D->getAttr<AsmLabelAttr>();
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if (!Attr)
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return true;
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if (Name == Attr->getLabel()) {
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Result = true;
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return false;
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}
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return true;
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}
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};
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}
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// isTriviallyRecursiveViaAsm - Check if this function calls another
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// decl that, because of the asm attribute, ends up pointing to itself.
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bool
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CodeGenModule::isTriviallyRecursiveViaAsm(const FunctionDecl *F) {
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if (getCXXABI().getMangleContext().shouldMangleDeclName(F))
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return false;
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FunctionIsDirectlyRecursive Walker(F);
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Walker.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));
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return Walker.Result;
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}
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bool
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CodeGenModule::shouldEmitFunction(const FunctionDecl *F) {
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if (getFunctionLinkage(F) != llvm::Function::AvailableExternallyLinkage)
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return true;
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if (F->hasAttr<AlwaysInlineAttr>())
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return true;
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if (CodeGenOpts.OptimizationLevel == 0)
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return false;
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// PR9614. Avoid cases where the source code is lying to us. An available
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// externally function should have an equivalent function somewhere else,
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// but a function that calls itself is clearly not equivalent to the real
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// implementation.
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// This happens in glibc's btowc and in some configure checks.
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if (isTriviallyRecursiveViaAsm(F))
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return false;
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return true;
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}
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void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
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const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
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@ -868,10 +925,7 @@ void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
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if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D)) {
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// At -O0, don't generate IR for functions with available_externally
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// linkage.
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if (CodeGenOpts.OptimizationLevel == 0 &&
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!Function->hasAttr<AlwaysInlineAttr>() &&
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getFunctionLinkage(Function)
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== llvm::Function::AvailableExternallyLinkage)
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if (!shouldEmitFunction(Function))
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return;
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if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
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@ -324,6 +324,8 @@ class CodeGenModule : public CodeGenTypeCache {
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void createOpenCLRuntime();
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void createCUDARuntime();
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bool isTriviallyRecursiveViaAsm(const FunctionDecl *F);
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bool shouldEmitFunction(const FunctionDecl *F);
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llvm::LLVMContext &VMContext;
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/// @name Cache for Blocks Runtime Globals
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@ -0,0 +1,15 @@
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// RUN: %clang_cc1 -emit-llvm %s -o - | FileCheck %s
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extern int foo_alias (void) __asm ("foo");
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inline int foo (void) {
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return foo_alias ();
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}
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int f(void) {
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return foo();
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}
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// CHECK-NOT: define
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// CHECK: define i32 @f()
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// CHECK: %call = call i32 @foo()
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// CHECK: ret i32 %call
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// CHECK-NOT: define
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