[CodeGen] Propagate may-alias'ness of lvalues with TBAA info
This patch fixes various places in clang to propagate may-alias
TBAA access descriptors during construction of lvalues, thus
eliminating the need for the LValueBaseInfo::MayAlias flag.
This is part of D38126 reworked to be a separate patch to
simplify review.
Differential Revision: https://reviews.llvm.org/D39008
llvm-svn: 316988
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index d3c2f47..d3b03e5 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1538,8 +1538,6 @@
Load->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node);
}
- if (BaseInfo.getMayAlias())
- TBAAInfo = CGM.getTBAAMayAliasAccessInfo();
CGM.DecorateInstructionWithTBAA(Load, TBAAInfo);
if (EmitScalarRangeCheck(Load, Ty, Loc)) {
@@ -1622,8 +1620,6 @@
Store->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node);
}
- if (BaseInfo.getMayAlias())
- TBAAInfo = CGM.getTBAAMayAliasAccessInfo();
CGM.DecorateInstructionWithTBAA(Store, TBAAInfo);
}
@@ -2170,10 +2166,7 @@
TBAAAccessInfo *PointeeTBAAInfo) {
llvm::LoadInst *Load = Builder.CreateLoad(RefLVal.getAddress(),
RefLVal.isVolatile());
- TBAAAccessInfo RefTBAAInfo = RefLVal.getTBAAInfo();
- if (RefLVal.getBaseInfo().getMayAlias())
- RefTBAAInfo = CGM.getTBAAMayAliasAccessInfo();
- CGM.DecorateInstructionWithTBAA(Load, RefTBAAInfo);
+ CGM.DecorateInstructionWithTBAA(Load, RefLVal.getTBAAInfo());
CharUnits Align = getNaturalTypeAlignment(RefLVal.getType()->getPointeeType(),
PointeeBaseInfo, PointeeTBAAInfo,
@@ -2356,11 +2349,10 @@
LValue CapLVal =
EmitCapturedFieldLValue(*this, CapturedStmtInfo->lookup(VD),
CapturedStmtInfo->getContextValue());
- bool MayAlias = CapLVal.getBaseInfo().getMayAlias();
return MakeAddrLValue(
Address(CapLVal.getPointer(), getContext().getDeclAlign(VD)),
- CapLVal.getType(), LValueBaseInfo(AlignmentSource::Decl, MayAlias),
- CGM.getTBAAAccessInfo(CapLVal.getType()));
+ CapLVal.getType(), LValueBaseInfo(AlignmentSource::Decl),
+ CapLVal.getTBAAInfo());
}
assert(isa<BlockDecl>(CurCodeDecl));
@@ -2504,7 +2496,7 @@
? emitAddrOfRealComponent(LV.getAddress(), LV.getType())
: emitAddrOfImagComponent(LV.getAddress(), LV.getType()));
LValue ElemLV = MakeAddrLValue(Component, T, LV.getBaseInfo(),
- CGM.getTBAAAccessInfo(T));
+ CGM.getTBAAInfoForSubobject(LV, T));
ElemLV.getQuals().addQualifiers(LV.getQuals());
return ElemLV;
}
@@ -3242,18 +3234,18 @@
Addr = emitArraySubscriptGEP(*this, Addr, Idx, EltType, /*inbounds*/ true,
SignedIndices, E->getExprLoc());
return MakeAddrLValue(Addr, EltType, LV.getBaseInfo(),
- CGM.getTBAAAccessInfo(EltType));
+ CGM.getTBAAInfoForSubobject(LV, EltType));
}
- LValueBaseInfo BaseInfo;
- TBAAAccessInfo TBAAInfo;
+ LValueBaseInfo EltBaseInfo;
+ TBAAAccessInfo EltTBAAInfo;
Address Addr = Address::invalid();
if (const VariableArrayType *vla =
getContext().getAsVariableArrayType(E->getType())) {
// The base must be a pointer, which is not an aggregate. Emit
// it. It needs to be emitted first in case it's what captures
// the VLA bounds.
- Addr = EmitPointerWithAlignment(E->getBase(), &BaseInfo, &TBAAInfo);
+ Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
// The element count here is the total number of non-VLA elements.
@@ -3277,7 +3269,7 @@
// Indexing over an interface, as in "NSString *P; P[4];"
// Emit the base pointer.
- Addr = EmitPointerWithAlignment(E->getBase(), &BaseInfo, &TBAAInfo);
+ Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
CharUnits InterfaceSize = getContext().getTypeSizeInChars(OIT);
@@ -3324,18 +3316,18 @@
*this, ArrayLV.getAddress(), {CGM.getSize(CharUnits::Zero()), Idx},
E->getType(), !getLangOpts().isSignedOverflowDefined(), SignedIndices,
E->getExprLoc());
- BaseInfo = ArrayLV.getBaseInfo();
- TBAAInfo = CGM.getTBAAAccessInfo(E->getType());
+ EltBaseInfo = ArrayLV.getBaseInfo();
+ EltTBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, E->getType());
} else {
// The base must be a pointer; emit it with an estimate of its alignment.
- Addr = EmitPointerWithAlignment(E->getBase(), &BaseInfo, &TBAAInfo);
+ Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
Addr = emitArraySubscriptGEP(*this, Addr, Idx, E->getType(),
!getLangOpts().isSignedOverflowDefined(),
SignedIndices, E->getExprLoc());
}
- LValue LV = MakeAddrLValue(Addr, E->getType(), BaseInfo, TBAAInfo);
+ LValue LV = MakeAddrLValue(Addr, E->getType(), EltBaseInfo, EltTBAAInfo);
if (getLangOpts().ObjC1 &&
getLangOpts().getGC() != LangOptions::NonGC) {
@@ -3374,9 +3366,12 @@
return CGF.Builder.CreateElementBitCast(Addr,
CGF.ConvertTypeForMem(ElTy));
}
- LValueBaseInfo TypeInfo;
- CharUnits Align = CGF.getNaturalTypeAlignment(ElTy, &TypeInfo);
- BaseInfo.mergeForCast(TypeInfo);
+ LValueBaseInfo TypeBaseInfo;
+ TBAAAccessInfo TypeTBAAInfo;
+ CharUnits Align = CGF.getNaturalTypeAlignment(ElTy, &TypeBaseInfo,
+ &TypeTBAAInfo);
+ BaseInfo.mergeForCast(TypeBaseInfo);
+ TBAAInfo = CGF.CGM.mergeTBAAInfoForCast(TBAAInfo, TypeTBAAInfo);
return Address(CGF.Builder.CreateLoad(BaseLVal.getAddress()), Align);
}
return CGF.EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
@@ -3522,7 +3517,7 @@
ResultExprTy, !getLangOpts().isSignedOverflowDefined(),
/*SignedIndices=*/false, E->getExprLoc());
BaseInfo = ArrayLV.getBaseInfo();
- TBAAInfo = CGM.getTBAAAccessInfo(ResultExprTy);
+ TBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, ResultExprTy);
} else {
Address Base = emitOMPArraySectionBase(*this, E->getBase(), BaseInfo,
TBAAInfo, BaseTy, ResultExprTy,
@@ -3712,7 +3707,7 @@
QualType fieldType =
field->getType().withCVRQualifiers(base.getVRQualifiers());
// TODO: Support TBAA for bit fields.
- LValueBaseInfo FieldBaseInfo(BaseInfo.getAlignmentSource(), false);
+ LValueBaseInfo FieldBaseInfo(BaseInfo.getAlignmentSource());
return LValue::MakeBitfield(Addr, Info, fieldType, FieldBaseInfo,
TBAAAccessInfo());
}
@@ -3723,16 +3718,14 @@
QualType FieldType = field->getType();
const RecordDecl *rec = field->getParent();
AlignmentSource BaseAlignSource = BaseInfo.getAlignmentSource();
- LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(BaseAlignSource), false);
+ LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(BaseAlignSource));
TBAAAccessInfo FieldTBAAInfo;
- if (BaseInfo.getMayAlias() || rec->hasAttr<MayAliasAttr>() ||
- FieldType->isVectorType()) {
- FieldBaseInfo.setMayAlias(true);
- FieldTBAAInfo = CGM.getTBAAMayAliasAccessInfo();
+ if (base.getTBAAInfo().isMayAlias() ||
+ rec->hasAttr<MayAliasAttr>() || FieldType->isVectorType()) {
+ FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo();
} else if (rec->isUnion()) {
// TODO: Support TBAA for unions.
- FieldBaseInfo.setMayAlias(true);
- FieldTBAAInfo = CGM.getTBAAMayAliasAccessInfo();
+ FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo();
} else {
// If no base type been assigned for the base access, then try to generate
// one for this base lvalue.
@@ -3818,13 +3811,14 @@
llvm::Type *llvmType = ConvertTypeForMem(FieldType);
V = Builder.CreateElementBitCast(V, llvmType, Field->getName());
- // TODO: access-path TBAA?
+ // TODO: Generate TBAA information that describes this access as a structure
+ // member access and not just an access to an object of the field's type. This
+ // should be similar to what we do in EmitLValueForField().
LValueBaseInfo BaseInfo = Base.getBaseInfo();
- LValueBaseInfo FieldBaseInfo(
- getFieldAlignmentSource(BaseInfo.getAlignmentSource()),
- BaseInfo.getMayAlias());
+ AlignmentSource FieldAlignSource = BaseInfo.getAlignmentSource();
+ LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(FieldAlignSource));
return MakeAddrLValue(V, FieldType, FieldBaseInfo,
- CGM.getTBAAAccessInfo(FieldType));
+ CGM.getTBAAInfoForSubobject(Base, FieldType));
}
LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
@@ -3937,11 +3931,10 @@
AlignmentSource alignSource =
std::max(lhs->getBaseInfo().getAlignmentSource(),
rhs->getBaseInfo().getAlignmentSource());
- bool MayAlias = lhs->getBaseInfo().getMayAlias() ||
- rhs->getBaseInfo().getMayAlias();
- return MakeAddrLValue(result, expr->getType(),
- LValueBaseInfo(alignSource, MayAlias),
- CGM.getTBAAAccessInfo(expr->getType()));
+ TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForConditionalOperator(
+ lhs->getTBAAInfo(), rhs->getTBAAInfo());
+ return MakeAddrLValue(result, expr->getType(), LValueBaseInfo(alignSource),
+ TBAAInfo);
} else {
assert((lhs || rhs) &&
"both operands of glvalue conditional are throw-expressions?");
@@ -4039,8 +4032,11 @@
This, DerivedClassDecl, E->path_begin(), E->path_end(),
/*NullCheckValue=*/false, E->getExprLoc());
+ // TODO: Support accesses to members of base classes in TBAA. For now, we
+ // conservatively pretend that the complete object is of the base class
+ // type.
return MakeAddrLValue(Base, E->getType(), LV.getBaseInfo(),
- CGM.getTBAAAccessInfo(E->getType()));
+ CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_ToUnion:
return EmitAggExprToLValue(E);
@@ -4068,7 +4064,7 @@
CFITCK_DerivedCast, E->getLocStart());
return MakeAddrLValue(Derived, E->getType(), LV.getBaseInfo(),
- CGM.getTBAAAccessInfo(E->getType()));
+ CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_LValueBitCast: {
// This must be a reinterpret_cast (or c-style equivalent).
@@ -4085,14 +4081,14 @@
CFITCK_UnrelatedCast, E->getLocStart());
return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(),
- CGM.getTBAAAccessInfo(E->getType()));
+ CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_ObjCObjectLValueCast: {
LValue LV = EmitLValue(E->getSubExpr());
Address V = Builder.CreateElementBitCast(LV.getAddress(),
ConvertType(E->getType()));
return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(),
- CGM.getTBAAAccessInfo(E->getType()));
+ CGM.getTBAAInfoForSubobject(LV, E->getType()));
}
case CK_ZeroToOCLQueue:
llvm_unreachable("NULL to OpenCL queue lvalue cast is not valid");