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Don't accept qualified 'int' main return types in C++ or standard C mode

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C++ [basic.start.main]p1: "It shall have a return type of type int"

ISO C is also clear about this, so only accept 'int' with qualifiers in GNUMode
C.

llvm-svn: 212171
This commit is contained in:
Alp Toker
2014-07-02 07:07:20 +00:00
parent f94baeb363
commit 70fc29ca86
3 changed files with 31 additions and 22 deletions
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49
clang/lib/Sema/SemaDecl.cpp
View File

@@ -7878,32 +7878,37 @@ void Sema::CheckMain(FunctionDecl* FD, const DeclSpec& DS) {
assert(T->isFunctionType() && "function decl is not of function type");
const FunctionType* FT = T->castAs<FunctionType>();
// All the standards say that main() should should return 'int'.
if (Context.hasSameUnqualifiedType(FT->getReturnType(), Context.IntTy)) {
if (getLangOpts().GNUMode && !getLangOpts().CPlusPlus) {
// 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.
// GCC in C mode accepts qualified 'int'.
if (Context.hasSameUnqualifiedType(FT->getReturnType(), Context.IntTy))
FD->setHasImplicitReturnZero(true);
else {
Diag(FD->getTypeSpecStartLoc(), diag::ext_main_returns_nonint);
SourceRange RTRange = FD->getReturnTypeSourceRange();
if (RTRange.isValid())
Diag(RTRange.getBegin(), diag::note_main_change_return_type)
<< FixItHint::CreateReplacement(RTRange, "int");
}
} else {
// 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 (getLangOpts().GNUMode && !getLangOpts().CPlusPlus) {
Diag(FD->getTypeSpecStartLoc(), diag::ext_main_returns_nonint);
SourceRange RTRange = FD->getReturnTypeSourceRange();
if (RTRange.isValid())
Diag(RTRange.getBegin(), diag::note_main_change_return_type)
<< FixItHint::CreateReplacement(RTRange, "int");
// Otherwise, this is just a flat-out error.
} else {
SourceRange RTRange = FD->getReturnTypeSourceRange();
Diag(FD->getTypeSpecStartLoc(), diag::err_main_returns_nonint)
<< (RTRange.isValid() ? FixItHint::CreateReplacement(RTRange, "int")
: FixItHint());
FD->setInvalidDecl(true);
// All the standards say that main() should return 'int'.
if (Context.hasSameType(FT->getReturnType(), Context.IntTy))
FD->setHasImplicitReturnZero(true);
else {
// Otherwise, this is just a flat-out error.
SourceRange RTRange = FD->getReturnTypeSourceRange();
Diag(FD->getTypeSpecStartLoc(), diag::err_main_returns_nonint)
<< (RTRange.isValid() ? FixItHint::CreateReplacement(RTRange, "int")
: FixItHint());
FD->setInvalidDecl(true);
}
}
// Treat protoless main() as nullary.

2
clang/test/CXX/basic/basic.start/basic.start.main/p2.cpp
View File

@@ -62,6 +62,8 @@ main( // expected-error {{first parameter of 'main' (argument count) must be of
) {
}
const int main(); // expected-error {{'main' must return 'int'}}
#elif TEST7
// expected-no-diagnostics

2
clang/test/Sema/c89.c
View File

@@ -111,6 +111,8 @@ const array_of_pointer_to_CI mine3;
void main() {} /* expected-error {{'main' must return 'int'}} */
const int main() {} /* expected-error {{'main' must return 'int'}} */
long long ll1 = /* expected-warning {{'long long' is an extension when C99 mode is not enabled}} */
-42LL; /* expected-warning {{'long long' is an extension when C99 mode is not enabled}} */
unsigned long long ull1 = /* expected-warning {{'long long' is an extension when C99 mode is not enabled}} */