[cfe-commits] r54533 - in /cfe/trunk: lib/Sema/Sema.h lib/Sema/SemaDecl.cpp test/Sema/tentative-decls.c
Steve Naroff
snaroff at apple.com
Fri Aug 8 10:50:36 PDT 2008
Author: snaroff
Date: Fri Aug 8 12:50:35 2008
New Revision: 54533
URL: http://llvm.org/viewvc/llvm-project?rev=54533&view=rev
Log:
Fix issues with C "tentative" definitions.
- Move checking from MergeVarDecl->FinializeDeclaratorGroup. Since MergeVarDecl is called before the initializer is attacted, it can't be done there (this removes a long standing FIXME).
- Add Sema::isTentativeDefinition() and Sema::CheckForFileScopedRedefinitions().
- Remove FIXME's and touch-up test case.
Still some more work to do (forthcoming)...
Modified:
cfe/trunk/lib/Sema/Sema.h
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/test/Sema/tentative-decls.c
Modified: cfe/trunk/lib/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/Sema.h?rev=54533&r1=54532&r2=54533&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/Sema.h (original)
+++ cfe/trunk/lib/Sema/Sema.h Fri Aug 8 12:50:35 2008
@@ -290,7 +290,9 @@
bool &Redeclaration);
VarDecl *MergeVarDecl(VarDecl *New, Decl *Old);
FunctionDecl *MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old);
-
+ bool isTentativeDefinition(VarDecl *VD);
+ void CheckForFileScopedRedefinitions(Scope *S, VarDecl *VD);
+
/// Helpers for dealing with function parameters
bool CheckParmsForFunctionDef(FunctionDecl *FD);
ImplicitParamDecl *CreateImplicitParameter(Scope *S, IdentifierInfo *Id,
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=54533&r1=54532&r2=54533&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Fri Aug 8 12:50:35 2008
@@ -104,7 +104,6 @@
return;
}
}
-
IdResolver.AddDecl(D);
}
@@ -411,12 +410,51 @@
return NewQType == OldQType;
}
+/// Predicate for C "tentative" external object definitions (C99 6.9.2).
+bool Sema::isTentativeDefinition(VarDecl *VD) {
+ if (VD->isFileVarDecl())
+ return (!VD->getInit() &&
+ (VD->getStorageClass() == VarDecl::None ||
+ VD->getStorageClass() == VarDecl::Static));
+ return false;
+}
+
+/// CheckForFileScopedRedefinitions - Make sure we forgo redefinition errors
+/// when dealing with C "tentative" external object definitions (C99 6.9.2).
+void Sema::CheckForFileScopedRedefinitions(Scope *S, VarDecl *VD) {
+ bool VDIsTentative = isTentativeDefinition(VD);
+
+ for (IdentifierResolver::iterator
+ I = IdResolver.begin(VD->getIdentifier(),
+ VD->getDeclContext(), false/*LookInParentCtx*/),
+ E = IdResolver.end(); I != E; ++I) {
+ if (*I != VD && IdResolver.isDeclInScope(*I, VD->getDeclContext(), S)) {
+ VarDecl *OldDecl = dyn_cast<VarDecl>(*I);
+
+ // Check for "tentative" definitions. We can't accomplish this in
+ // MergeVarDecl since the initializer hasn't been attached.
+ if (!OldDecl || isTentativeDefinition(OldDecl) || VDIsTentative)
+ continue;
+
+ // Handle __private_extern__ just like extern.
+ if (OldDecl->getStorageClass() != VarDecl::Extern &&
+ OldDecl->getStorageClass() != VarDecl::PrivateExtern &&
+ VD->getStorageClass() != VarDecl::Extern &&
+ VD->getStorageClass() != VarDecl::PrivateExtern) {
+ Diag(VD->getLocation(), diag::err_redefinition, VD->getName());
+ Diag(OldDecl->getLocation(), diag::err_previous_definition);
+ }
+ }
+ }
+}
+
/// MergeVarDecl - We just parsed a variable 'New' which has the same name
/// and scope as a previous declaration 'Old'. Figure out how to resolve this
/// situation, merging decls or emitting diagnostics as appropriate.
///
-/// FIXME: Need to carefully consider tentative definition rules (C99 6.9.2p2).
-/// For example, we incorrectly complain about i1, i4 from C99 6.9.2p4.
+/// Tentative definition rules (C99 6.9.2p2) are checked by
+/// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
+/// definitions here, since the initializer hasn't been attached.
///
VarDecl *Sema::MergeVarDecl(VarDecl *New, Decl *OldD) {
// Verify the old decl was also a variable.
@@ -454,34 +492,8 @@
Diag(Old->getLocation(), diag::err_previous_definition);
return New;
}
- // We've verified the types match, now handle "tentative" definitions.
- if (Old->isFileVarDecl() && New->isFileVarDecl()) {
- // Handle C "tentative" external object definitions (C99 6.9.2).
- bool OldIsTentative = false;
- bool NewIsTentative = false;
-
- if (!Old->getInit() &&
- (Old->getStorageClass() == VarDecl::None ||
- Old->getStorageClass() == VarDecl::Static))
- OldIsTentative = true;
-
- // FIXME: this check doesn't work (since the initializer hasn't been
- // attached yet). This check should be moved to FinalizeDeclaratorGroup.
- // Unfortunately, by the time we get to FinializeDeclaratorGroup, we've
- // thrown out the old decl.
- if (!New->getInit() &&
- (New->getStorageClass() == VarDecl::None ||
- New->getStorageClass() == VarDecl::Static))
- ; // change to NewIsTentative = true; once the code is moved.
-
- if (NewIsTentative || OldIsTentative)
- return New;
- }
- // Handle __private_extern__ just like extern.
- if (Old->getStorageClass() != VarDecl::Extern &&
- Old->getStorageClass() != VarDecl::PrivateExtern &&
- New->getStorageClass() != VarDecl::Extern &&
- New->getStorageClass() != VarDecl::PrivateExtern) {
+ // File scoped variables are analyzed in FinalizeDeclaratorGroup.
+ if (!New->isFileVarDecl()) {
Diag(New->getLocation(), diag::err_redefinition, New->getName());
Diag(Old->getLocation(), diag::err_previous_definition);
}
@@ -1431,9 +1443,7 @@
// storage-class specifier or with the storage-class specifier "static",
// constitutes a tentative definition. Note: A tentative definition with
// external linkage is valid (C99 6.2.2p5).
- if (IDecl && !IDecl->getInit() &&
- (IDecl->getStorageClass() == VarDecl::Static ||
- IDecl->getStorageClass() == VarDecl::None)) {
+ if (isTentativeDefinition(IDecl)) {
if (T->isIncompleteArrayType()) {
// C99 6.9.2 (p2, p5): Implicit initialization causes an incomplete
// array to be completed. Don't issue a diagnostic.
@@ -1446,6 +1456,8 @@
IDecl->setInvalidDecl();
}
}
+ if (IDecl->isFileVarDecl())
+ CheckForFileScopedRedefinitions(S, IDecl);
}
return NewGroup;
}
Modified: cfe/trunk/test/Sema/tentative-decls.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/tentative-decls.c?rev=54533&r1=54532&r2=54533&view=diff
==============================================================================
--- cfe/trunk/test/Sema/tentative-decls.c (original)
+++ cfe/trunk/test/Sema/tentative-decls.c Fri Aug 8 12:50:35 2008
@@ -11,16 +11,19 @@
int i1 = 1; // expected-error{{previous definition is here}}
int i1 = 2; // expected-error{{redefinition of 'i1'}} // expected-error{{previous definition is here}}
-// FIXME: the following should not be an error (see related FIXME in Sema::MergeVarDecl).
-int i1; // expected-error{{redefinition of 'i1'}}
+int i1;
int i1;
extern int i1; // expected-error{{previous definition is here}}
static int i1; // expected-error{{static declaration of 'i1' follows non-static declaration}} expected-error{{previous definition is here}}
-int i1 = 3; // expected-error{{non-static declaration of 'i1' follows static declaration}}
+int i1 = 3; // expected-error{{redefinition of 'i1'}} expected-error{{non-static declaration of 'i1' follows static declaration}}
__private_extern__ int pExtern;
int pExtern = 0;
+int i4;
+int i4;
+extern int i4;
+
void func() {
extern int i1; // expected-error{{previous definition is here}}
static int i1; // expected-error{{static declaration of 'i1' follows non-static declaration}}
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