[cfe-commits] r126540 - in /cfe/trunk: lib/CodeGen/CGExpr.cpp lib/CodeGen/CodeGenModule.h test/CodeGen/may-alias.c test/CodeGenCXX/anonymous-union-member-initializer.cpp
John McCall
rjmccall at apple.com
Sat Feb 26 00:07:02 PST 2011
Author: rjmccall
Date: Sat Feb 26 02:07:02 2011
New Revision: 126540
URL: http://llvm.org/viewvc/llvm-project?rev=126540&view=rev
Log:
Pretty up the emission of field l-values and use volatile and TBAA when
loading references as part of that. Use 'char' TBAA when accessing
(immediate!) fields of a may_alias struct; fixes PR9307.
Modified:
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/lib/CodeGen/CodeGenModule.h
cfe/trunk/test/CodeGen/may-alias.c
cfe/trunk/test/CodeGenCXX/anonymous-union-member-initializer.cpp
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=126540&r1=126539&r2=126540&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Sat Feb 26 02:07:02 2011
@@ -1610,39 +1610,67 @@
}
}
-LValue CodeGenFunction::EmitLValueForField(llvm::Value *BaseValue,
- const FieldDecl *Field,
- unsigned CVRQualifiers) {
- if (Field->isBitField())
- return EmitLValueForBitfield(BaseValue, Field, CVRQualifiers);
-
- const CGRecordLayout &RL =
- CGM.getTypes().getCGRecordLayout(Field->getParent());
- unsigned idx = RL.getLLVMFieldNo(Field);
- llvm::Value *V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
-
- // Match union field type.
- if (Field->getParent()->isUnion()) {
- const llvm::Type *FieldTy =
- CGM.getTypes().ConvertTypeForMem(Field->getType());
- const llvm::PointerType *BaseTy =
- cast<llvm::PointerType>(BaseValue->getType());
- unsigned AS = BaseTy->getAddressSpace();
- V = Builder.CreateBitCast(V,
- llvm::PointerType::get(FieldTy, AS),
- "tmp");
+LValue CodeGenFunction::EmitLValueForField(llvm::Value *baseAddr,
+ const FieldDecl *field,
+ unsigned cvr) {
+ if (field->isBitField())
+ return EmitLValueForBitfield(baseAddr, field, cvr);
+
+ const RecordDecl *rec = field->getParent();
+ QualType type = field->getType();
+
+ bool mayAlias = rec->hasAttr<MayAliasAttr>();
+
+ llvm::Value *addr;
+ if (rec->isUnion()) {
+ // For unions, we just cast to the appropriate type.
+ assert(!type->isReferenceType() && "union has reference member");
+
+ const llvm::Type *llvmType = CGM.getTypes().ConvertTypeForMem(type);
+ unsigned AS =
+ cast<llvm::PointerType>(baseAddr->getType())->getAddressSpace();
+ addr = Builder.CreateBitCast(baseAddr, llvmType->getPointerTo(AS),
+ field->getName());
+ } else {
+ // For structs, we GEP to the field that the record layout suggests.
+ unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
+ addr = Builder.CreateStructGEP(baseAddr, idx, field->getName());
+
+ // If this is a reference field, load the reference right now.
+ if (const ReferenceType *refType = type->getAs<ReferenceType>()) {
+ llvm::LoadInst *load = Builder.CreateLoad(addr, "ref");
+ if (cvr & Qualifiers::Volatile) load->setVolatile(true);
+
+ if (CGM.shouldUseTBAA()) {
+ llvm::MDNode *tbaa;
+ if (mayAlias)
+ tbaa = CGM.getTBAAInfo(getContext().CharTy);
+ else
+ tbaa = CGM.getTBAAInfo(type);
+ CGM.DecorateInstruction(load, tbaa);
+ }
+
+ addr = load;
+ mayAlias = false;
+ type = refType->getPointeeType();
+ cvr = 0; // qualifiers don't recursively apply to referencee
+ }
}
- if (Field->getType()->isReferenceType())
- V = Builder.CreateLoad(V, "tmp");
- unsigned Alignment = getContext().getDeclAlign(Field).getQuantity();
- LValue LV = MakeAddrLValue(V, Field->getType(), Alignment);
- LV.getQuals().addCVRQualifiers(CVRQualifiers);
+ unsigned alignment = getContext().getDeclAlign(field).getQuantity();
+ LValue LV = MakeAddrLValue(addr, type, alignment);
+ LV.getQuals().addCVRQualifiers(cvr);
// __weak attribute on a field is ignored.
if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
LV.getQuals().removeObjCGCAttr();
-
+
+ // Fields of may_alias structs act like 'char' for TBAA purposes.
+ // FIXME: this should get propagated down through anonymous structs
+ // and unions.
+ if (mayAlias && LV.getTBAAInfo())
+ LV.setTBAAInfo(CGM.getTBAAInfo(getContext().CharTy));
+
return LV;
}
Modified: cfe/trunk/lib/CodeGen/CodeGenModule.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.h?rev=126540&r1=126539&r2=126540&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenModule.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenModule.h Sat Feb 26 02:07:02 2011
@@ -295,6 +295,8 @@
const TargetCodeGenInfo &getTargetCodeGenInfo();
bool isTargetDarwin() const;
+ bool shouldUseTBAA() const { return TBAA != 0; }
+
llvm::MDNode *getTBAAInfo(QualType QTy);
static void DecorateInstruction(llvm::Instruction *Inst,
Modified: cfe/trunk/test/CodeGen/may-alias.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/may-alias.c?rev=126540&r1=126539&r2=126540&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/may-alias.c (original)
+++ cfe/trunk/test/CodeGen/may-alias.c Sat Feb 26 02:07:02 2011
@@ -8,12 +8,21 @@
void test0(aliasing_int *ai, int *i)
{
+// CHECK: store i32 0, i32* %{{.*}}, !tbaa !1
*ai = 0;
+// CHECK: store i32 1, i32* %{{.*}}, !tbaa !3
*i = 1;
}
-// CHECK: store i32 0, i32* %{{.*}}, !tbaa !1
-// CHECK: store i32 1, i32* %{{.*}}, !tbaa !3
+// PR9307
+struct Test1 { int x; };
+struct Test1MA { int x; } __attribute__((may_alias));
+void test1(struct Test1MA *p1, struct Test1 *p2) {
+ // CHECK: store i32 2, i32* {{%.*}}, !tbaa !1
+ p1->x = 2;
+ // CHECK: store i32 3, i32* {{%.*}}, !tbaa !3
+ p2->x = 3;
+}
// CHECK: !0 = metadata !{metadata !"any pointer", metadata !1}
// CHECK: !1 = metadata !{metadata !"omnipotent char", metadata !2}
Modified: cfe/trunk/test/CodeGenCXX/anonymous-union-member-initializer.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/anonymous-union-member-initializer.cpp?rev=126540&r1=126539&r2=126540&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/anonymous-union-member-initializer.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/anonymous-union-member-initializer.cpp Sat Feb 26 02:07:02 2011
@@ -84,11 +84,11 @@
// CHECK: define void @_ZN5test31AC2Ev(
// CHECK: [[THIS:%.*]] = load
// CHECK-NEXT: [[UNION:%.*]] = getelementptr inbounds {{.*}} [[THIS]], i32 0, i32 0
- // CHECK-NEXT: [[STRUCT:%.*]] = getelementptr inbounds {{.*}} [[UNION]], i32 0, i32 0
+ // CHECK-NEXT: [[STRUCT:%.*]] = bitcast {{.*}}* [[UNION]] to
// CHECK-NEXT: [[CALLBACK:%.*]] = getelementptr inbounds {{.*}} [[STRUCT]], i32 0, i32 0
// CHECK-NEXT: store void (i8*)* null, void (i8*)** [[CALLBACK]]
// CHECK-NEXT: [[UNION:%.*]] = getelementptr inbounds {{.*}} [[THIS]], i32 0, i32 0
- // CHECK-NEXT: [[STRUCT:%.*]] = getelementptr inbounds {{.*}} [[UNION]], i32 0, i32 0
+ // CHECK-NEXT: [[STRUCT:%.*]] = bitcast {{.*}}* [[UNION]] to
// CHECK-NEXT: [[CVALUE:%.*]] = getelementptr inbounds {{.*}} [[STRUCT]], i32 0, i32 1
// CHECK-NEXT: store i8* null, i8** [[CVALUE]]
}
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