New fix for pr17535.
This is a fixed version of r193161. In order to handle
void foo() __attribute__((alias("bar")));
void bar() {}
void zed() __attribute__((alias("foo")));
it is not enough to delay aliases to the end of the TU, we have to do two
passes over them to find if they are defined or not.
This can be implemented by producing alias as we go and just doing the second
pass at the end. This has the advantage that other parts of clang that were
expecting alias to be processed in order don't have to be changed.
This patch also handles cyclic aliases.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193188 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 96ae437..d0f34dd 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -37,6 +37,7 @@
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/Version.h"
#include "clang/Frontend/CodeGenOptions.h"
+#include "clang/Sema/SemaDiagnostic.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/Triple.h"
#include "llvm/IR/CallingConv.h"
@@ -171,8 +172,42 @@
CUDARuntime = CreateNVCUDARuntime(*this);
}
+void CodeGenModule::checkAliases() {
+ bool Error = false;
+ for (std::vector<GlobalDecl>::iterator I = Aliases.begin(),
+ E = Aliases.end(); I != E; ++I) {
+ const GlobalDecl &GD = *I;
+ const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
+ const AliasAttr *AA = D->getAttr<AliasAttr>();
+ StringRef MangledName = getMangledName(GD);
+ llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
+ llvm::GlobalAlias *Alias = cast<llvm::GlobalAlias>(Entry);
+ llvm::GlobalValue *GV = Alias->getAliasedGlobal();
+ if (GV->isDeclaration()) {
+ Error = true;
+ getDiags().Report(AA->getLocation(), diag::err_alias_to_undefined);
+ } else if (!Alias->resolveAliasedGlobal(/*stopOnWeak*/ false)) {
+ Error = true;
+ getDiags().Report(AA->getLocation(), diag::err_cyclic_alias);
+ }
+ }
+ if (!Error)
+ return;
+
+ for (std::vector<GlobalDecl>::iterator I = Aliases.begin(),
+ E = Aliases.end(); I != E; ++I) {
+ const GlobalDecl &GD = *I;
+ StringRef MangledName = getMangledName(GD);
+ llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
+ llvm::GlobalAlias *Alias = cast<llvm::GlobalAlias>(Entry);
+ Alias->replaceAllUsesWith(llvm::UndefValue::get(Alias->getType()));
+ Alias->eraseFromParent();
+ }
+}
+
void CodeGenModule::Release() {
EmitDeferred();
+ checkAliases();
EmitCXXGlobalInitFunc();
EmitCXXGlobalDtorFunc();
EmitCXXThreadLocalInitFunc();
@@ -2088,6 +2123,8 @@
if (Entry && !Entry->isDeclaration())
return;
+ Aliases.push_back(GD);
+
llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
// Create a reference to the named value. This ensures that it is emitted
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 066009c..25aaae6 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -275,6 +275,10 @@
/// is done.
std::vector<GlobalDecl> DeferredDeclsToEmit;
+ /// List of alias we have emitted. Used to make sure that what they point to
+ /// is defined once we get to the end of the of the translation unit.
+ std::vector<GlobalDecl> Aliases;
+
/// DeferredVTables - A queue of (optional) vtables to consider emitting.
std::vector<const CXXRecordDecl*> DeferredVTables;
@@ -1077,6 +1081,8 @@
/// was deferred.
void EmitDeferred();
+ void checkAliases();
+
/// EmitDeferredVTables - Emit any vtables which we deferred and
/// still have a use for.
void EmitDeferredVTables();