[cfe-commits] r72428 - in /cfe/trunk: include/clang/AST/Decl.h lib/AST/Decl.cpp lib/AST/Expr.cpp lib/AST/ExprConstant.cpp lib/AST/StmtIterator.cpp lib/Frontend/PCHReaderDecl.cpp lib/Sema/SemaDecl.cpp lib/Sema/SemaDeclCXX.cpp
Douglas Gregor
dgregor at apple.com
Tue May 26 11:54:04 PDT 2009
Author: dgregor
Date: Tue May 26 13:54:04 2009
New Revision: 72428
URL: http://llvm.org/viewvc/llvm-project?rev=72428&view=rev
Log:
When evaluating a VarDecl as a constant or determining whether it is
an integral constant expression, maintain a cache of the value and the
is-an-ICE flag within the VarDecl itself. This eliminates
exponential-time behavior of the Fibonacci template metaprogram.
Modified:
cfe/trunk/include/clang/AST/Decl.h
cfe/trunk/lib/AST/Decl.cpp
cfe/trunk/lib/AST/Expr.cpp
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/lib/AST/StmtIterator.cpp
cfe/trunk/lib/Frontend/PCHReaderDecl.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/lib/Sema/SemaDeclCXX.cpp
Modified: cfe/trunk/include/clang/AST/Decl.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Decl.h (original)
+++ cfe/trunk/include/clang/AST/Decl.h Tue May 26 13:54:04 2009
@@ -14,6 +14,7 @@
#ifndef LLVM_CLANG_AST_DECL_H
#define LLVM_CLANG_AST_DECL_H
+#include "clang/AST/APValue.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/ExternalASTSource.h"
@@ -186,6 +187,27 @@
static bool classof(const ValueDecl *D) { return true; }
};
+/// \brief Structure used to store a statement, the constant value to
+/// which it was evaluated (if any), and whether or not the statement
+/// is an integral constant expression (if known).
+struct EvaluatedStmt {
+ EvaluatedStmt() : WasEvaluated(false), CheckedICE(false), IsICE(false) { }
+
+ /// \brief Whether this statement was already evaluated.
+ bool WasEvaluated : 1;
+
+ /// \brief Whether we already checked whether this statement was an
+ /// integral constant expression.
+ bool CheckedICE : 1;
+
+ /// \brief Whether this statement is an integral constant
+ /// expression. Only valid if CheckedICE is true.
+ bool IsICE : 1;
+
+ Stmt *Value;
+ APValue Evaluated;
+};
+
/// VarDecl - An instance of this class is created to represent a variable
/// declaration or definition.
class VarDecl : public ValueDecl {
@@ -201,7 +223,7 @@
static const char *getStorageClassSpecifierString(StorageClass SC);
private:
- Stmt *Init;
+ mutable llvm::PointerUnion<Stmt *, EvaluatedStmt *> Init;
// FIXME: This can be packed into the bitfields in Decl.
unsigned SClass : 3;
bool ThreadSpecified : 1;
@@ -220,7 +242,7 @@
protected:
VarDecl(Kind DK, DeclContext *DC, SourceLocation L, IdentifierInfo *Id,
QualType T, StorageClass SC, SourceLocation TSSL = SourceLocation())
- : ValueDecl(DK, DC, L, Id, T), Init(0),
+ : ValueDecl(DK, DC, L, Id, T), Init(),
ThreadSpecified(false), HasCXXDirectInit(false),
DeclaredInCondition(false), PreviousDeclaration(0),
TypeSpecStartLoc(TSSL) {
@@ -243,10 +265,95 @@
TypeSpecStartLoc = SL;
}
- const Expr *getInit() const { return (const Expr*) Init; }
- Expr *getInit() { return (Expr*) Init; }
- void setInit(Expr *I) { Init = (Stmt*) I; }
-
+ const Expr *getInit() const {
+ if (Init.isNull())
+ return 0;
+
+ const Stmt *S = Init.dyn_cast<Stmt *>();
+ if (!S)
+ S = Init.get<EvaluatedStmt *>()->Value;
+
+ return (const Expr*) S;
+ }
+ Expr *getInit() {
+ if (Init.isNull())
+ return 0;
+
+ Stmt *S = Init.dyn_cast<Stmt *>();
+ if (!S)
+ S = Init.get<EvaluatedStmt *>()->Value;
+
+ return (Expr*) S;
+ }
+
+ /// \brief Retrieve the address of the initializer expression.
+ Stmt **getInitAddress() {
+ if (Init.is<Stmt *>())
+ return reinterpret_cast<Stmt **>(&Init); // FIXME: ugly hack
+ return &Init.get<EvaluatedStmt *>()->Value;
+ }
+
+ void setInit(ASTContext &C, Expr *I);
+
+ /// \brief Note that constant evaluation has computed the given
+ /// value for this variable's initializer.
+ void setEvaluatedValue(ASTContext &C, const APValue &Value) const {
+ EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>();
+ if (!Eval) {
+ Stmt *S = Init.get<Stmt *>();
+ Eval = new (C) EvaluatedStmt;
+ Eval->Value = S;
+ Init = Eval;
+ }
+
+ Eval->WasEvaluated = true;
+ Eval->Evaluated = Value;
+ }
+
+ /// \brief Return the already-evaluated value of this variable's
+ /// initializer, or NULL if the value is not yet known.
+ APValue *getEvaluatedValue() const {
+ if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>())
+ if (Eval->WasEvaluated)
+ return &Eval->Evaluated;
+
+ return 0;
+ }
+
+ /// \brief Determines whether it is already known whether the
+ /// initializer is an integral constant expression or not.
+ bool isInitKnownICE() const {
+ if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>())
+ return Eval->CheckedICE;
+
+ return false;
+ }
+
+ /// \brief Determines whether the initializer is an integral
+ /// constant expression.
+ ///
+ /// \pre isInitKnownICE()
+ bool isInitICE() const {
+ assert(isInitKnownICE() &&
+ "Check whether we already know that the initializer is an ICE");
+ return Init.get<EvaluatedStmt *>()->IsICE;
+ }
+
+ /// \brief Note that we now know whether the initializer is an
+ /// integral constant expression.
+ void setInitKnownICE(ASTContext &C, bool IsICE) const {
+ EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>();
+ if (!Eval) {
+ Stmt *S = Init.get<Stmt *>();
+ Eval = new (C) EvaluatedStmt;
+ Eval->Value = S;
+ Init = Eval;
+ }
+
+ Eval->CheckedICE = true;
+ Eval->IsICE = IsICE;
+ }
+
/// \brief Retrieve the definition of this variable, which may come
/// from a previous declaration. Def will be set to the VarDecl that
/// contains the initializer, and the result will be that
Modified: cfe/trunk/lib/AST/Decl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Decl.cpp?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Decl.cpp (original)
+++ cfe/trunk/lib/AST/Decl.cpp Tue May 26 13:54:04 2009
@@ -89,6 +89,15 @@
return getType();
}
+void VarDecl::setInit(ASTContext &C, Expr *I) {
+ if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>()) {
+ Eval->~EvaluatedStmt();
+ C.Deallocate(Eval);
+ }
+
+ Init = I;
+ }
+
bool VarDecl::isExternC(ASTContext &Context) const {
if (!Context.getLangOptions().CPlusPlus)
return (getDeclContext()->isTranslationUnit() &&
@@ -287,8 +296,13 @@
void VarDecl::Destroy(ASTContext& C) {
Expr *Init = getInit();
- if (Init)
+ if (Init) {
Init->Destroy(C);
+ if (EvaluatedStmt *Eval = this->Init.dyn_cast<EvaluatedStmt *>()) {
+ Eval->~EvaluatedStmt();
+ C.Deallocate(Eval);
+ }
+ }
this->~VarDecl();
C.Deallocate((void *)this);
}
Modified: cfe/trunk/lib/AST/Expr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Expr.cpp (original)
+++ cfe/trunk/lib/AST/Expr.cpp Tue May 26 13:54:04 2009
@@ -1210,8 +1210,21 @@
// type initialized by an ICE can be used in ICEs.
if (const VarDecl *Dcl =
dyn_cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl())) {
- if (const Expr *Init = Dcl->getInit())
- return CheckICE(Init, Ctx);
+ if (Dcl->isInitKnownICE()) {
+ // We have already checked whether this subexpression is an
+ // integral constant expression.
+ if (Dcl->isInitICE())
+ return NoDiag();
+ else
+ return ICEDiag(2, E->getLocStart());
+ }
+
+ if (const Expr *Init = Dcl->getInit()) {
+ ICEDiag Result = CheckICE(Init, Ctx);
+ // Cache the result of the ICE test.
+ Dcl->setInitKnownICE(Ctx, Result.Val == 0);
+ return Result;
+ }
}
}
return ICEDiag(2, E->getLocStart());
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Tue May 26 13:54:04 2009
@@ -700,8 +700,17 @@
// In C, they can also be folded, although they are not ICEs.
if (E->getType().getCVRQualifiers() == QualType::Const) {
if (const VarDecl *D = dyn_cast<VarDecl>(E->getDecl())) {
- if (const Expr *Init = D->getInit())
- return Visit(const_cast<Expr*>(Init));
+ if (APValue *V = D->getEvaluatedValue())
+ return Success(V->getInt(), E);
+ if (const Expr *Init = D->getInit()) {
+ if (Visit(const_cast<Expr*>(Init))) {
+ // Cache the evaluated value in the variable declaration.
+ D->setEvaluatedValue(Info.Ctx, Result);
+ return true;
+ }
+
+ return false;
+ }
}
}
Modified: cfe/trunk/lib/AST/StmtIterator.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/StmtIterator.cpp?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/lib/AST/StmtIterator.cpp (original)
+++ cfe/trunk/lib/AST/StmtIterator.cpp Tue May 26 13:54:04 2009
@@ -140,14 +140,14 @@
if (inDeclGroup()) {
VarDecl* VD = cast<VarDecl>(*DGI);
- return VD->Init;
+ return *VD->getInitAddress();
}
assert (inDecl());
if (VarDecl* VD = dyn_cast<VarDecl>(decl)) {
assert (VD->Init);
- return VD->Init;
+ return *VD->getInitAddress();
}
EnumConstantDecl* ECD = cast<EnumConstantDecl>(decl);
Modified: cfe/trunk/lib/Frontend/PCHReaderDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/PCHReaderDecl.cpp?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/PCHReaderDecl.cpp (original)
+++ cfe/trunk/lib/Frontend/PCHReaderDecl.cpp Tue May 26 13:54:04 2009
@@ -342,7 +342,7 @@
cast_or_null<VarDecl>(Reader.GetDecl(Record[Idx++])));
VD->setTypeSpecStartLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
if (Record[Idx++])
- VD->setInit(Reader.ReadDeclExpr());
+ VD->setInit(*Reader.getContext(), Reader.ReadDeclExpr());
}
void PCHDeclReader::VisitImplicitParamDecl(ImplicitParamDecl *PD) {
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Tue May 26 13:54:04 2009
@@ -2581,7 +2581,7 @@
// };
// Attach the initializer
- VDecl->setInit(Init);
+ VDecl->setInit(Context, Init);
// C++ [class.mem]p4:
// A member-declarator can contain a constant-initializer only
@@ -2644,7 +2644,7 @@
}
// Attach the initializer to the decl.
- VDecl->setInit(Init);
+ VDecl->setInit(Context, Init);
// If the previous declaration of VDecl was a tentative definition,
// remove it from the set of tentative definitions.
Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=72428&r1=72427&r2=72428&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Tue May 26 13:54:04 2009
@@ -1776,7 +1776,7 @@
Expr **Exprs, unsigned NumExprs) {
Expr *Temp = CXXConstructExpr::Create(Context, VD, DeclInitType, Constructor,
false, Exprs, NumExprs);
- VD->setInit(Temp);
+ VD->setInit(Context, Temp);
}
/// AddCXXDirectInitializerToDecl - This action is called immediately after
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