[cfe-commits] r97733 - in /cfe/trunk: lib/CodeGen/CGExpr.cpp lib/CodeGen/CodeGenModule.cpp lib/CodeGen/CodeGenModule.h test/CodeGen/attr-weakref.c test/CodeGen/attr-weakref2.c test/CodeGen/attributes.c
Rafael Espindola
rafael.espindola at gmail.com
Thu Mar 4 10:17:24 PST 2010
Author: rafael
Date: Thu Mar 4 12:17:24 2010
New Revision: 97733
URL: http://llvm.org/viewvc/llvm-project?rev=97733&view=rev
Log:
Fix PR6473.
Clang's support for weakref is now better than llvm-gcc's :-)
We don't introduce a new symbol and we correctly mark undefined references weak only if there is no
definition or regular undefined references in the same file.
Added:
cfe/trunk/test/CodeGen/attr-weakref.c
cfe/trunk/test/CodeGen/attr-weakref2.c
Modified:
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/lib/CodeGen/CodeGenModule.cpp
cfe/trunk/lib/CodeGen/CodeGenModule.h
cfe/trunk/test/CodeGen/attributes.c
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=97733&r1=97732&r2=97733&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Thu Mar 4 12:17:24 2010
@@ -1062,6 +1062,16 @@
LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
const NamedDecl *ND = E->getDecl();
+ if (ND->hasAttr<WeakRefAttr>()) {
+ const ValueDecl* VD = cast<ValueDecl>(ND);
+ llvm::Constant *Aliasee = CGM.GetWeakRefReference(VD);
+
+ Qualifiers Quals = MakeQualifiers(E->getType());
+ LValue LV = LValue::MakeAddr(Aliasee, Quals);
+
+ return LV;
+ }
+
if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
// Check if this is a global variable.
Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=97733&r1=97732&r2=97733&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original)
+++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Thu Mar 4 12:17:24 2010
@@ -619,9 +619,41 @@
return false;
}
+llvm::Constant *CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
+ const AliasAttr *AA = VD->getAttr<AliasAttr>();
+ assert(AA && "No alias?");
+
+ const llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
+
+ // Unique the name through the identifier table.
+ const char *AliaseeName =
+ getContext().Idents.get(AA->getAliasee()).getNameStart();
+
+ // See if there is already something with the target's name in the module.
+ llvm::GlobalValue *Entry = GlobalDeclMap[AliaseeName];
+
+ llvm::Constant *Aliasee;
+ if (isa<llvm::FunctionType>(DeclTy))
+ Aliasee = GetOrCreateLLVMFunction(AliaseeName, DeclTy, GlobalDecl());
+ else
+ Aliasee = GetOrCreateLLVMGlobal(AliaseeName,
+ llvm::PointerType::getUnqual(DeclTy), 0);
+ if (!Entry) {
+ llvm::GlobalValue* F = cast<llvm::GlobalValue>(Aliasee);
+ F->setLinkage(llvm::Function::ExternalWeakLinkage);
+ WeakRefReferences.insert(F);
+ }
+
+ return Aliasee;
+}
+
void CodeGenModule::EmitGlobal(GlobalDecl GD) {
const ValueDecl *Global = cast<ValueDecl>(GD.getDecl());
+ // Weak references don't produce any output by themselves.
+ if (Global->hasAttr<WeakRefAttr>())
+ return;
+
// If this is an alias definition (which otherwise looks like a declaration)
// emit it now.
if (Global->hasAttr<AliasAttr>())
@@ -708,6 +740,14 @@
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
if (Entry) {
+ if (WeakRefReferences.count(Entry)) {
+ const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl());
+ if (FD && !FD->hasAttr<WeakAttr>())
+ Entry->setLinkage(llvm::Function::ExternalLinkage);
+
+ WeakRefReferences.erase(Entry);
+ }
+
if (Entry->getType()->getElementType() == Ty)
return Entry;
@@ -817,6 +857,13 @@
// Lookup the entry, lazily creating it if necessary.
llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
if (Entry) {
+ if (WeakRefReferences.count(Entry)) {
+ if (D && !D->hasAttr<WeakAttr>())
+ Entry->setLinkage(llvm::Function::ExternalLinkage);
+
+ WeakRefReferences.erase(Entry);
+ }
+
if (Entry->getType() == Ty)
return Entry;
Modified: cfe/trunk/lib/CodeGen/CodeGenModule.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.h?rev=97733&r1=97732&r2=97733&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenModule.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenModule.h Thu Mar 4 12:17:24 2010
@@ -29,6 +29,7 @@
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/ValueHandle.h"
#include <list>
@@ -117,6 +118,11 @@
/// pointer lookups instead of full string lookups.
llvm::DenseMap<const char*, llvm::GlobalValue*> GlobalDeclMap;
+ // WeakRefReferences - A set of references that have only been seen via
+ // a weakref so far. This is used to remove the weak of the reference if we ever
+ // see a direct reference or a definition.
+ llvm::SmallPtrSet<llvm::GlobalValue*, 10> WeakRefReferences;
+
/// \brief Contains the strings used for mangled names.
///
/// FIXME: Eventually, this should map from the semantic/canonical
@@ -243,6 +249,9 @@
void BuildThunksForVirtual(GlobalDecl GD);
void BuildThunksForVirtualRecursive(GlobalDecl GD, GlobalDecl BaseOGD);
+ /// GetWeakRefReference - Get a reference to the target of VD.
+ llvm::Constant *GetWeakRefReference(const ValueDecl *VD);
+
/// BuildThunk - Build a thunk for the given method.
llvm::Constant *BuildThunk(GlobalDecl GD, bool Extern,
const ThunkAdjustment &ThisAdjustment);
Added: cfe/trunk/test/CodeGen/attr-weakref.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/attr-weakref.c?rev=97733&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/attr-weakref.c (added)
+++ cfe/trunk/test/CodeGen/attr-weakref.c Thu Mar 4 12:17:24 2010
@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -emit-llvm -triple i386-linux-gnu -o %t %s
+// RUN: FileCheck --input-file=%t %s
+
+// CHECK: declare extern_weak void @test1_f()
+void test1_f(void);
+static void test1_g(void) __attribute__((weakref("test1_f")));
+void test1_h(void) {
+ test1_g();
+}
+
+// CHECK: define void @test2_f()
+void test2_f(void) {}
+static void test2_g(void) __attribute__((weakref("test2_f")));
+void test2_h(void) {
+ test2_g();
+}
+
+// CHECK: declare void @test3_f()
+void test3_f(void);
+static void test3_g(void) __attribute__((weakref("test3_f")));
+void test3_foo(void) {
+ test3_f();
+}
+void test3_h(void) {
+ test3_g();
+}
+
+// CHECK: define void @test4_f()
+void test4_f(void);
+static void test4_g(void) __attribute__((weakref("test4_f")));
+void test4_h(void) {
+ test4_g();
+}
+void test4_f(void) {}
+
+// CHECK: declare void @test5_f()
+void test5_f(void);
+static void test5_g(void) __attribute__((weakref("test5_f")));
+void test5_h(void) {
+ test5_g();
+}
+void test5_foo(void) {
+ test5_f();
+}
+
+// CHECK: declare extern_weak void @test6_f()
+void test6_f(void) __attribute__((weak));
+static void test6_g(void) __attribute__((weakref("test6_f")));
+void test6_h(void) {
+ test6_g();
+}
+void test6_foo(void) {
+ test6_f();
+}
Added: cfe/trunk/test/CodeGen/attr-weakref2.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/attr-weakref2.c?rev=97733&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/attr-weakref2.c (added)
+++ cfe/trunk/test/CodeGen/attr-weakref2.c Thu Mar 4 12:17:24 2010
@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -emit-llvm -triple i386-linux-gnu -o %t %s
+// RUN: FileCheck --input-file=%t %s
+
+// CHECK: @test1_f = extern_weak global i32
+extern int test1_f;
+static int test1_g __attribute__((weakref("test1_f")));
+int test1_h(void) {
+ return test1_g;
+}
+
+// CHECK: @test2_f = common global i32 0, align 4
+int test2_f;
+static int test2_g __attribute__((weakref("test2_f")));
+int test2_h(void) {
+ return test2_g;
+}
+
+// CHECK: @test3_f = external global i32
+extern int test3_f;
+static int test3_g __attribute__((weakref("test3_f")));
+int test3_foo(void) {
+ return test3_f;
+}
+int test3_h(void) {
+ return test3_g;
+}
+
+// CHECK: @test4_f = common global i32 0, align 4
+extern int test4_f;
+static int test4_g __attribute__((weakref("test4_f")));
+int test4_h(void) {
+ return test4_g;
+}
+int test4_f;
+
+// CHECK: @test5_f = external global i32
+extern int test5_f;
+static int test5_g __attribute__((weakref("test5_f")));
+int test5_h(void) {
+ return test5_g;
+}
+int test5_foo(void) {
+ return test5_f;
+}
+
+// CHECK: @test6_f = extern_weak global i32
+extern int test6_f __attribute__((weak));
+static int test6_g __attribute__((weakref("test6_f")));
+int test6_h(void) {
+ return test6_g;
+}
+int test6_foo(void) {
+ return test6_f;
+}
Modified: cfe/trunk/test/CodeGen/attributes.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/attributes.c?rev=97733&r1=97732&r2=97733&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/attributes.c (original)
+++ cfe/trunk/test/CodeGen/attributes.c Thu Mar 4 12:17:24 2010
@@ -30,12 +30,6 @@
void __t8() {}
void t9() __attribute__((weak, alias("__t8")));
-static void t22(void) __attribute__((weakref("t8")));
-// CHECK: @t22 = alias weak void ()* @t8
-
-static void t23(void) __attribute__((weakref, alias("t8")));
-// CHECK: @t23 = alias weak void ()* @t8
-
// CHECK: declare extern_weak i32 @t15()
int __attribute__((weak_import)) t15(void);
int t17() {
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