From 25d944af5d8d665611e09956954f10896c1071f6 Mon Sep 17 00:00:00 2001 From: Douglas Gregor Date: Tue, 24 Feb 2009 04:26:15 +0000 Subject: [PATCH] In C, when we see a function declaration within a local scope, export that declaration to global scope so that it can be found from other scopes. This allows us to diagnose redeclaration errors for external declarations across scopes. We also warn when name lookup finds such an out-of-scope declaration. This is part of ; we'll also need to do the same thing for variables. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@65373 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/clang/Basic/DiagnosticSemaKinds.def | 2 + lib/Sema/SemaDecl.cpp | 52 +++++++++++++++++++++ lib/Sema/SemaExpr.cpp | 25 +++++++++- test/Sema/function-redecl.c | 28 +++++++++++ 4 files changed, 106 insertions(+), 1 deletion(-) diff --git a/include/clang/Basic/DiagnosticSemaKinds.def b/include/clang/Basic/DiagnosticSemaKinds.def index 2016d4ff47..24bca6a0cf 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.def +++ b/include/clang/Basic/DiagnosticSemaKinds.def @@ -84,6 +84,8 @@ DIAG(err_declarator_need_ident, ERROR, "declarator requires an identifier") DIAG(err_bad_language, ERROR, "unknown linkage language") +DIAG(warn_use_out_of_scope_declaration, WARNING, + "use of out-of-scope declaration of %0") /// Built-in functions. DIAG(ext_implicit_lib_function_decl, EXTWARN, diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp index 634017330d..00136badfe 100644 --- a/lib/Sema/SemaDecl.cpp +++ b/lib/Sema/SemaDecl.cpp @@ -2033,6 +2033,58 @@ Sema::ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC, InvalidDecl = true; } } + + if (!getLangOptions().CPlusPlus && CurContext->isFunctionOrMethod()) { + // If this is a function declaration in local scope, inject its + // name into the top-level scope so that it will be visible to + // later uses and declarations of the same function, since the + // function is external. + // FIXME: We don't do this in C++ because, although we would like + // to get the extra checking that this operation implies, + // the declaration itself is not visible according to C++'s rules. + IdentifierResolver::iterator I = IdResolver.begin(Name), + IEnd = IdResolver.end(); + NamedDecl *PrevIdDecl = 0; + while (I != IEnd && !isa((*I)->getDeclContext())) { + PrevIdDecl = *I; + ++I; + } + + if (I == IEnd) { + // No name with this identifier has been declared at translation + // unit scope. Add this name into the appropriate scope. + if (PrevIdDecl) + IdResolver.AddShadowedDecl(NewFD, PrevIdDecl); + else + IdResolver.AddDecl(NewFD); + TUScope->AddDecl(NewFD); + return NewFD; + } + + if (isa(*I)) { + // The first thing we found was a tag declaration, so insert + // this function so that it will be found before the tag + // declaration. + if (PrevIdDecl) + IdResolver.AddShadowedDecl(NewFD, PrevIdDecl); + else + IdResolver.AddDecl(NewFD); + TUScope->AddDecl(NewFD); + } else if (isa(*I) && NewFD->declarationReplaces(*I)) { + // We found a previous declaration of the same function. Replace + // that declaration with this one. + TUScope->RemoveDecl(*I); + TUScope->AddDecl(NewFD); + IdResolver.RemoveDecl(*I); + if (PrevIdDecl) + IdResolver.AddShadowedDecl(NewFD, PrevIdDecl); + else + IdResolver.AddDecl(NewFD); + } + + return NewFD; + } + return NewFD; } diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp index aef66619f6..a58752cb42 100644 --- a/lib/Sema/SemaExpr.cpp +++ b/lib/Sema/SemaExpr.cpp @@ -70,12 +70,13 @@ bool Sema::DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc) { } // See if this is a deleted function. - if (FunctionDecl *FD = dyn_cast(D)) + if (FunctionDecl *FD = dyn_cast(D)) { if (FD->isDeleted()) { Diag(Loc, diag::err_deleted_function_use); Diag(D->getLocation(), diag::note_unavailable_here) << true; return true; } + } // See if the decl is unavailable if (D->getAttr()) { @@ -83,6 +84,28 @@ bool Sema::DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc) { Diag(D->getLocation(), diag::note_unavailable_here) << 0; } + if (D->getDeclContext()->isFunctionOrMethod() && + !D->getDeclContext()->Encloses(CurContext)) { + // We've found the name of a function or variable that was + // declared with external linkage within another function (and, + // therefore, a scope where we wouldn't normally see the + // declaration). Once we've made sure that no previous declaration + // was properly made visible, produce a warning. + bool HasGlobalScopedDeclaration = false; + for (const FunctionDecl *FD = dyn_cast(D); FD; + FD = FD->getPreviousDeclaration()) { + if (FD->getDeclContext()->isFileContext()) { + HasGlobalScopedDeclaration = true; + break; + } + } + // FIXME: do the same thing for variable declarations + + if (!HasGlobalScopedDeclaration) { + Diag(Loc, diag::warn_use_out_of_scope_declaration) << D; + Diag(D->getLocation(), diag::note_previous_declaration); + } + } return false; } diff --git a/test/Sema/function-redecl.c b/test/Sema/function-redecl.c index 4be0322722..daa5044dd0 100644 --- a/test/Sema/function-redecl.c +++ b/test/Sema/function-redecl.c @@ -58,3 +58,31 @@ void test2() { } } } + +// +int outer1(int); // expected-note{{previous declaration is here}} +struct outer3 { }; +int outer4(int); +int outer5; // expected-note{{previous definition is here}} +int *outer7(int); + +void outer_test() { + int outer1(float); // expected-error{{conflicting types for 'outer1'}} + int outer2(int); // expected-note{{previous declaration is here}} + int outer3(int); // expected-note{{previous declaration is here}} + int outer4(int); // expected-note{{previous declaration is here}} + int outer5(int); // expected-error{{redefinition of 'outer5' as different kind of symbol}} + int* outer6(int); // expected-note{{previous declaration is here}} + int *outer7(int); + + int *ip7 = outer7(6); +} + +int outer2(float); // expected-error{{conflicting types for 'outer2'}} +int outer3(float); // expected-error{{conflicting types for 'outer3'}} +int outer4(float); // expected-error{{conflicting types for 'outer4'}} + +void outer_test2(int x) { + int* ip = outer6(x); // expected-warning{{use of out-of-scope declaration of 'outer6'}} + int *ip2 = outer7(x); +} -- 2.40.0