Warn about non-int main() results in GNU C mode instead of erroring.
Based on a patch by Vasiliy Korchagin!
llvm-svn: 150500
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index de9fecc..304304b 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5794,9 +5794,23 @@
QualType T = FD->getType();
assert(T->isFunctionType() && "function decl is not of function type");
- const FunctionType* FT = T->getAs<FunctionType>();
+ const FunctionType* FT = T->castAs<FunctionType>();
- if (!Context.hasSameUnqualifiedType(FT->getResultType(), Context.IntTy)) {
+ // All the standards say that main() should should return 'int'.
+ if (Context.hasSameUnqualifiedType(FT->getResultType(), Context.IntTy)) {
+ // In C and C++, main magically returns 0 if you fall off the end;
+ // set the flag which tells us that.
+ // This is C++ [basic.start.main]p5 and C99 5.1.2.2.3.
+ FD->setHasImplicitReturnZero(true);
+
+ // In C with GNU extensions we allow main() to have non-integer return
+ // type, but we should warn about the extension, and we disable the
+ // implicit-return-zero rule.
+ } else if (getLangOptions().GNUMode && !getLangOptions().CPlusPlus) {
+ Diag(FD->getTypeSpecStartLoc(), diag::ext_main_returns_nonint);
+
+ // Otherwise, this is just a flat-out error.
+ } else {
Diag(FD->getTypeSpecStartLoc(), diag::err_main_returns_nonint);
FD->setInvalidDecl(true);
}
@@ -7259,16 +7273,11 @@
if (FD) {
FD->setBody(Body);
- if (FD->isMain()) {
- // C and C++ allow for main to automagically return 0.
- // Implements C++ [basic.start.main]p5 and C99 5.1.2.2.3.
- FD->setHasImplicitReturnZero(true);
+
+ // If the function implicitly returns zero (like 'main') or is naked,
+ // don't complain about missing return statements.
+ if (FD->hasImplicitReturnZero() || FD->hasAttr<NakedAttr>())
WP.disableCheckFallThrough();
- } else if (FD->hasAttr<NakedAttr>()) {
- // If the function is marked 'naked', don't complain about missing return
- // statements.
- WP.disableCheckFallThrough();
- }
// MSVC permits the use of pure specifier (=0) on function definition,
// defined at class scope, warn about this non standard construct.