[cfe-commits] r147561 - in /cfe/trunk: include/clang/AST/APValue.h lib/AST/APValue.cpp lib/AST/Expr.cpp lib/AST/ExprConstant.cpp lib/CodeGen/CGExprConstant.cpp lib/Sema/SemaChecking.cpp test/CodeGenCXX/const-init.cpp
Eli Friedman
eli.friedman at gmail.com
Wed Jan 4 15:13:47 PST 2012
Author: efriedma
Date: Wed Jan 4 17:13:47 2012
New Revision: 147561
URL: http://llvm.org/viewvc/llvm-project?rev=147561&view=rev
Log:
Add an APValue representation for the difference between two address-of-label expressions. Add support to Evaluate and CGExprConstant for generating/handling them. Remove the special-case for such differences in Expr::isConstantInitializer.
With that done, remove a bunch of buggy code from CGExprConstant for handling scalar expressions which is no longer necessary.
Fixes PR11705.
Modified:
cfe/trunk/include/clang/AST/APValue.h
cfe/trunk/lib/AST/APValue.cpp
cfe/trunk/lib/AST/Expr.cpp
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/lib/CodeGen/CGExprConstant.cpp
cfe/trunk/lib/Sema/SemaChecking.cpp
cfe/trunk/test/CodeGenCXX/const-init.cpp
Modified: cfe/trunk/include/clang/AST/APValue.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/APValue.h?rev=147561&r1=147560&r2=147561&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/APValue.h (original)
+++ cfe/trunk/include/clang/AST/APValue.h Wed Jan 4 17:13:47 2012
@@ -21,6 +21,7 @@
#include "llvm/ADT/PointerUnion.h"
namespace clang {
+ class AddrLabelExpr;
class ASTContext;
class CharUnits;
class DiagnosticBuilder;
@@ -49,7 +50,8 @@
Array,
Struct,
Union,
- MemberPointer
+ MemberPointer,
+ AddrLabelDiff
};
typedef llvm::PointerUnion<const ValueDecl *, const Expr *> LValueBase;
typedef llvm::PointerIntPair<const Decl *, 1, bool> BaseOrMemberType;
@@ -100,6 +102,10 @@
UnionData();
~UnionData();
};
+ struct AddrLabelDiffData {
+ const AddrLabelExpr* LHSExpr;
+ const AddrLabelExpr* RHSExpr;
+ };
struct MemberPointerData;
enum {
@@ -155,6 +161,10 @@
ArrayRef<const CXXRecordDecl*> Path) : Kind(Uninitialized) {
MakeMemberPointer(Member, IsDerivedMember, Path);
}
+ APValue(const AddrLabelExpr* LHSExpr, const AddrLabelExpr* RHSExpr)
+ : Kind(Uninitialized) {
+ MakeAddrLabelDiff(); setAddrLabelDiff(LHSExpr, RHSExpr);
+ }
~APValue() {
MakeUninit();
@@ -172,6 +182,7 @@
bool isStruct() const { return Kind == Struct; }
bool isUnion() const { return Kind == Union; }
bool isMemberPointer() const { return Kind == MemberPointer; }
+ bool isAddrLabelDiff() const { return Kind == AddrLabelDiff; }
void dump() const;
void dump(raw_ostream &OS) const;
@@ -316,6 +327,15 @@
bool isMemberPointerToDerivedMember() const;
ArrayRef<const CXXRecordDecl*> getMemberPointerPath() const;
+ const AddrLabelExpr* getAddrLabelDiffLHS() const {
+ assert(isAddrLabelDiff() && "Invalid accessor");
+ return ((AddrLabelDiffData*)(char*)Data)->LHSExpr;
+ }
+ const AddrLabelExpr* getAddrLabelDiffRHS() const {
+ assert(isAddrLabelDiff() && "Invalid accessor");
+ return ((AddrLabelDiffData*)(char*)Data)->RHSExpr;
+ }
+
void setInt(const APSInt &I) {
assert(isInt() && "Invalid accessor");
*(APSInt*)(char*)Data = I;
@@ -353,6 +373,11 @@
((UnionData*)(char*)Data)->Field = Field;
*((UnionData*)(char*)Data)->Value = Value;
}
+ void setAddrLabelDiff(const AddrLabelExpr* LHSExpr,
+ const AddrLabelExpr* RHSExpr) {
+ ((AddrLabelDiffData*)(char*)Data)->LHSExpr = LHSExpr;
+ ((AddrLabelDiffData*)(char*)Data)->RHSExpr = RHSExpr;
+ }
const APValue &operator=(const APValue &RHS);
@@ -397,6 +422,11 @@
}
void MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
ArrayRef<const CXXRecordDecl*> Path);
+ void MakeAddrLabelDiff() {
+ assert(isUninit() && "Bad state change");
+ new ((void*)(char*)Data) AddrLabelDiffData();
+ Kind = AddrLabelDiff;
+ }
};
} // end namespace clang.
Modified: cfe/trunk/lib/AST/APValue.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/APValue.cpp?rev=147561&r1=147560&r2=147561&view=diff
==============================================================================
--- cfe/trunk/lib/AST/APValue.cpp (original)
+++ cfe/trunk/lib/AST/APValue.cpp Wed Jan 4 17:13:47 2012
@@ -149,6 +149,8 @@
MakeMemberPointer(RHS.getMemberPointerDecl(),
RHS.isMemberPointerToDerivedMember(),
RHS.getMemberPointerPath());
+ else if (RHS.isAddrLabelDiff())
+ MakeAddrLabelDiff();
}
if (isInt())
setInt(RHS.getInt());
@@ -177,8 +179,11 @@
getStructBase(I) = RHS.getStructBase(I);
for (unsigned I = 0, N = RHS.getStructNumFields(); I != N; ++I)
getStructField(I) = RHS.getStructField(I);
- } else if (isUnion())
+ } else if (isUnion()) {
setUnion(RHS.getUnionField(), RHS.getUnionValue());
+ } else if (isAddrLabelDiff()) {
+ setAddrLabelDiff(RHS.getAddrLabelDiffLHS(), RHS.getAddrLabelDiffRHS());
+ }
return *this;
}
@@ -203,6 +208,8 @@
((UnionData*)(char*)Data)->~UnionData();
else if (Kind == MemberPointer)
((MemberPointerData*)(char*)Data)->~MemberPointerData();
+ else if (Kind == AddrLabelDiff)
+ ((AddrLabelDiffData*)(char*)Data)->~AddrLabelDiffData();
Kind = Uninitialized;
}
@@ -285,6 +292,9 @@
case MemberPointer:
OS << "MemberPointer: <todo>";
return;
+ case AddrLabelDiff:
+ OS << "AddrLabelDiff: <todo>";
+ return;
}
llvm_unreachable("Unknown APValue kind!");
}
@@ -472,6 +482,11 @@
}
Out << "0";
return;
+ case APValue::AddrLabelDiff:
+ Out << "&&" << getAddrLabelDiffLHS()->getLabel()->getName();
+ Out << " - ";
+ Out << "&&" << getAddrLabelDiffRHS()->getLabel()->getName();
+ return;
}
llvm_unreachable("Unknown APValue kind!");
}
Modified: cfe/trunk/lib/AST/Expr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=147561&r1=147560&r2=147561&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Expr.cpp (original)
+++ cfe/trunk/lib/AST/Expr.cpp Wed Jan 4 17:13:47 2012
@@ -2530,16 +2530,6 @@
return Exp->getSubExpr()->isConstantInitializer(Ctx, false);
break;
}
- case BinaryOperatorClass: {
- // Special case &&foo - &&bar. It would be nice to generalize this somehow
- // but this handles the common case.
- const BinaryOperator *Exp = cast<BinaryOperator>(this);
- if (Exp->getOpcode() == BO_Sub &&
- isa<AddrLabelExpr>(Exp->getLHS()->IgnoreParenNoopCasts(Ctx)) &&
- isa<AddrLabelExpr>(Exp->getRHS()->IgnoreParenNoopCasts(Ctx)))
- return true;
- break;
- }
case CXXFunctionalCastExprClass:
case CXXStaticCastExprClass:
case ImplicitCastExprClass:
@@ -2558,23 +2548,6 @@
CE->getCastKind() == CK_ConstructorConversion)
return CE->getSubExpr()->isConstantInitializer(Ctx, false);
- // Handle things like (int)(&&x-&&y). It's a bit nasty, but we support it.
- if (CE->getCastKind() == CK_IntegralCast) {
- const Expr *E = CE->getSubExpr()->IgnoreParenNoopCasts(Ctx);
- while (const CastExpr *InnerCE = dyn_cast<CastExpr>(E)) {
- if (InnerCE->getCastKind() != CK_IntegralCast)
- break;
- E = InnerCE->getSubExpr()->IgnoreParenNoopCasts(Ctx);
- }
-
- if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
- if (BO->getOpcode() == BO_Sub &&
- isa<AddrLabelExpr>(BO->getLHS()->IgnoreParenNoopCasts(Ctx)) &&
- isa<AddrLabelExpr>(BO->getRHS()->IgnoreParenNoopCasts(Ctx)))
- return true;
- }
- }
-
break;
}
case MaterializeTemporaryExprClass:
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=147561&r1=147560&r2=147561&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Wed Jan 4 17:13:47 2012
@@ -210,6 +210,8 @@
CCValue(const ValueDecl *D, bool IsDerivedMember,
ArrayRef<const CXXRecordDecl*> Path) :
APValue(D, IsDerivedMember, Path) {}
+ CCValue(const AddrLabelExpr* LHSExpr, const AddrLabelExpr* RHSExpr) :
+ APValue(LHSExpr, RHSExpr) {}
CallStackFrame *getLValueFrame() const {
assert(getKind() == LValue);
@@ -856,6 +858,7 @@
case APValue::Array:
case APValue::Struct:
case APValue::Union:
+ case APValue::AddrLabelDiff:
return false;
}
@@ -3997,6 +4000,23 @@
// Reject differing bases from the normal codepath; we special-case
// comparisons to null.
if (!HasSameBase(LHSValue, RHSValue)) {
+ if (E->getOpcode() == BO_Sub) {
+ // Handle &&A - &&B.
+ // FIXME: We're missing a check that both labels have the same
+ // associated function; I'm not sure how to write this check.
+ if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
+ return false;
+ const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr*>();
+ const Expr *RHSExpr = LHSValue.Base.dyn_cast<const Expr*>();
+ if (!LHSExpr || !RHSExpr)
+ return false;
+ const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
+ const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
+ if (!LHSAddrExpr || !RHSAddrExpr)
+ return false;
+ Result = CCValue(LHSAddrExpr, RHSAddrExpr);
+ return true;
+ }
// Inequalities and subtractions between unrelated pointers have
// unspecified or undefined behavior.
if (!E->isEqualityOp())
@@ -4091,6 +4111,25 @@
return true;
}
+ if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
+ // Handle (intptr_t)&&A - (intptr_t)&&B.
+ // FIXME: We're missing a check that both labels have the same
+ // associated function; I'm not sure how to write this check.
+ if (!LHSVal.getLValueOffset().isZero() ||
+ !RHSVal.getLValueOffset().isZero())
+ return false;
+ const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
+ const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
+ if (!LHSExpr || !RHSExpr)
+ return false;
+ const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
+ const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
+ if (!LHSAddrExpr || !RHSAddrExpr)
+ return false;
+ Result = CCValue(LHSAddrExpr, RHSAddrExpr);
+ return true;
+ }
+
// All the following cases expect both operands to be an integer
if (!LHSVal.isInt() || !RHSVal.isInt())
return Error(E);
@@ -4398,6 +4437,13 @@
return false;
if (!Result.isInt()) {
+ // Allow casts of address-of-label differences if they are no-ops
+ // or narrowing. (The narrowing case isn't actually guaranteed to
+ // be constant-evaluatable except in some narrow cases which are hard
+ // to detect here. We let it through on the assumption the user knows
+ // what they are doing.)
+ if (Result.isAddrLabelDiff())
+ return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
// Only allow casts of lvalues if they are lossless.
return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
}
Modified: cfe/trunk/lib/CodeGen/CGExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprConstant.cpp?rev=147561&r1=147560&r2=147561&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprConstant.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp Wed Jan 4 17:13:47 2012
@@ -500,27 +500,6 @@
return 0;
}
- llvm::Constant *VisitBinSub(BinaryOperator *E) {
- // This must be a pointer/pointer subtraction. This only happens for
- // address of label.
- if (!isa<AddrLabelExpr>(E->getLHS()->IgnoreParenNoopCasts(CGM.getContext())) ||
- !isa<AddrLabelExpr>(E->getRHS()->IgnoreParenNoopCasts(CGM.getContext())))
- return 0;
-
- llvm::Constant *LHS = CGM.EmitConstantExpr(E->getLHS(),
- E->getLHS()->getType(), CGF);
- llvm::Constant *RHS = CGM.EmitConstantExpr(E->getRHS(),
- E->getRHS()->getType(), CGF);
-
- llvm::Type *ResultType = ConvertType(E->getType());
- LHS = llvm::ConstantExpr::getPtrToInt(LHS, ResultType);
- RHS = llvm::ConstantExpr::getPtrToInt(RHS, ResultType);
-
- // No need to divide by element size, since addr of label is always void*,
- // which has size 1 in GNUish.
- return llvm::ConstantExpr::getSub(LHS, RHS);
- }
-
llvm::Constant *VisitCastExpr(CastExpr* E) {
Expr *subExpr = E->getSubExpr();
llvm::Constant *C = CGM.EmitConstantExpr(subExpr, subExpr->getType(), CGF);
@@ -570,13 +549,6 @@
case CK_NoOp:
return C;
- case CK_CPointerToObjCPointerCast:
- case CK_BlockPointerToObjCPointerCast:
- case CK_AnyPointerToBlockPointerCast:
- case CK_BitCast:
- if (C->getType() == destType) return C;
- return llvm::ConstantExpr::getBitCast(C, destType);
-
case CK_Dependent: llvm_unreachable("saw dependent cast!");
// These will never be supported.
@@ -595,7 +567,12 @@
case CK_ConstructorConversion:
return 0;
- // These should eventually be supported.
+ // These don't need to be handled here because Evaluate knows how to
+ // evaluate all scalar expressions which can be constant-evaluated.
+ case CK_CPointerToObjCPointerCast:
+ case CK_BlockPointerToObjCPointerCast:
+ case CK_AnyPointerToBlockPointerCast:
+ case CK_BitCast:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay:
case CK_BaseToDerived:
@@ -613,53 +590,17 @@
case CK_IntegralComplexToBoolean:
case CK_IntegralComplexCast:
case CK_IntegralComplexToFloatingComplex:
- return 0;
-
case CK_PointerToIntegral:
- if (!E->getType()->isBooleanType())
- return llvm::ConstantExpr::getPtrToInt(C, destType);
- // fallthrough
-
case CK_PointerToBoolean:
- return llvm::ConstantExpr::getICmp(llvm::CmpInst::ICMP_EQ, C,
- llvm::ConstantPointerNull::get(cast<llvm::PointerType>(C->getType())));
-
case CK_NullToPointer:
- return llvm::ConstantPointerNull::get(cast<llvm::PointerType>(destType));
-
- case CK_IntegralCast: {
- bool isSigned = subExpr->getType()->isSignedIntegerOrEnumerationType();
- return llvm::ConstantExpr::getIntegerCast(C, destType, isSigned);
- }
-
- case CK_IntegralToPointer: {
- bool isSigned = subExpr->getType()->isSignedIntegerOrEnumerationType();
- C = llvm::ConstantExpr::getIntegerCast(C, CGM.IntPtrTy, isSigned);
- return llvm::ConstantExpr::getIntToPtr(C, destType);
- }
-
+ case CK_IntegralCast:
+ case CK_IntegralToPointer:
case CK_IntegralToBoolean:
- return llvm::ConstantExpr::getICmp(llvm::CmpInst::ICMP_EQ, C,
- llvm::Constant::getNullValue(C->getType()));
-
case CK_IntegralToFloating:
- if (subExpr->getType()->isSignedIntegerOrEnumerationType())
- return llvm::ConstantExpr::getSIToFP(C, destType);
- else
- return llvm::ConstantExpr::getUIToFP(C, destType);
-
case CK_FloatingToIntegral:
- if (E->getType()->isSignedIntegerOrEnumerationType())
- return llvm::ConstantExpr::getFPToSI(C, destType);
- else
- return llvm::ConstantExpr::getFPToUI(C, destType);
-
case CK_FloatingToBoolean:
- return llvm::ConstantExpr::getFCmp(llvm::CmpInst::FCMP_UNE, C,
- llvm::Constant::getNullValue(C->getType()));
-
case CK_FloatingCast:
- return llvm::ConstantExpr::getFPCast(C, destType);
+ return 0;
}
llvm_unreachable("Invalid CastKind");
}
@@ -1081,6 +1022,23 @@
}
return llvm::ConstantVector::get(Inits);
}
+ case APValue::AddrLabelDiff: {
+ const AddrLabelExpr *LHSExpr = Result.Val.getAddrLabelDiffLHS();
+ const AddrLabelExpr *RHSExpr = Result.Val.getAddrLabelDiffRHS();
+ llvm::Constant *LHS = EmitConstantExpr(LHSExpr, LHSExpr->getType(), CGF);
+ llvm::Constant *RHS = EmitConstantExpr(RHSExpr, RHSExpr->getType(), CGF);
+
+ // Compute difference
+ llvm::Type *ResultType = getTypes().ConvertType(E->getType());
+ LHS = llvm::ConstantExpr::getPtrToInt(LHS, IntPtrTy);
+ RHS = llvm::ConstantExpr::getPtrToInt(RHS, IntPtrTy);
+ llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
+
+ // LLVM os a bit sensitive about the exact format of the
+ // address-of-label difference; make sure to truncate after
+ // the subtraction.
+ return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);
+ }
case APValue::Array:
case APValue::Struct:
case APValue::Union:
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=147561&r1=147560&r2=147561&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Wed Jan 4 17:13:47 2012
@@ -3239,7 +3239,7 @@
// FIXME: The only reason we need to pass the type in here is to get
// the sign right on this one case. It would be nice if APValue
// preserved this.
- assert(result.isLValue());
+ assert(result.isLValue() || result.isAddrLabelDiff());
return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType());
}
Modified: cfe/trunk/test/CodeGenCXX/const-init.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/const-init.cpp?rev=147561&r1=147560&r2=147561&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/const-init.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/const-init.cpp Wed Jan 4 17:13:47 2012
@@ -56,3 +56,16 @@
const MutableMember MM = { 0 };
return ++MM.n;
}
+
+// Make sure we don't try to fold this in the frontend; the backend can't
+// handle it.
+// CHECK: @PR11705 = global i128 0
+__int128_t PR11705 = (__int128_t)&PR11705;
+
+// Make sure we don't try to fold this either.
+// CHECK: @_ZZ23UnfoldableAddrLabelDiffvE1x = internal global i128 0
+void UnfoldableAddrLabelDiff() { static __int128_t x = (long)&&a-(long)&&b; a:b:return;}
+
+// But make sure we do fold this.
+// CHECK: @_ZZ21FoldableAddrLabelDiffvE1x = internal global i64 sub (i64 ptrtoint (i8* blockaddress(@_Z21FoldableAddrLabelDiffv, %a)
+void FoldableAddrLabelDiff() { static long x = (long)&&a-(long)&&b; a:b:return;}
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