Files
clang-p2996/clang/test/Sema/gnu-flags.c
Richard Smith 552c6c2328 PR44406: Follow behavior of array bound constant folding in more recent versions of GCC.
Old GCC used to aggressively fold VLAs to constant-bound arrays at block
scope in GNU mode. That's non-conforming, and more modern versions of
GCC only do this at file scope. Update Clang to do the same.

Also promote the warning for this from off-by-default to on-by-default
in all cases; more recent versions of GCC likewise warn on this by
default.

This is still slightly more permissive than GCC, as pointed out in
PR44406, as we still fold VLAs to constant arrays in structs, but that
seems justifiable given that we don't support VLA-in-struct (and don't
intend to ever support it), but GCC does.

Differential Revision: https://reviews.llvm.org/D89523
2020-10-16 14:34:35 -07:00

174 lines
5.2 KiB
C

// RUN: %clang_cc1 -fsyntax-only -verify %s -DNONE -Wno-gnu
// RUN: %clang_cc1 -fsyntax-only -verify %s -DALL -Wgnu
// RUN: %clang_cc1 -fsyntax-only -verify %s -DALL -Wno-gnu \
// RUN: -Wgnu-alignof-expression -Wgnu-case-range -Wgnu-complex-integer -Wgnu-conditional-omitted-operand \
// RUN: -Wgnu-empty-initializer -Wgnu-label-as-value -Wgnu-statement-expression \
// RUN: -Wgnu-compound-literal-initializer -Wgnu-flexible-array-initializer \
// RUN: -Wgnu-redeclared-enum -Wgnu-folding-constant -Wgnu-empty-struct \
// RUN: -Wgnu-union-cast -Wgnu-variable-sized-type-not-at-end
// RUN: %clang_cc1 -fsyntax-only -verify %s -DNONE -Wgnu \
// RUN: -Wno-gnu-alignof-expression -Wno-gnu-case-range -Wno-gnu-complex-integer -Wno-gnu-conditional-omitted-operand \
// RUN: -Wno-gnu-empty-initializer -Wno-gnu-label-as-value -Wno-gnu-statement-expression \
// RUN: -Wno-gnu-compound-literal-initializer -Wno-gnu-flexible-array-initializer \
// RUN: -Wno-gnu-redeclared-enum -Wno-gnu-folding-constant -Wno-gnu-empty-struct \
// RUN: -Wno-gnu-union-cast -Wno-gnu-variable-sized-type-not-at-end
// Additional disabled tests:
// %clang_cc1 -fsyntax-only -verify %s -DALIGNOF -Wno-gnu -Wgnu-alignof-expression
// %clang_cc1 -fsyntax-only -verify %s -DCASERANGE -Wno-gnu -Wgnu-case-range
// %clang_cc1 -fsyntax-only -verify %s -DCOMPLEXINT -Wno-gnu -Wgnu-complex-integer
// %clang_cc1 -fsyntax-only -verify %s -DOMITTEDOPERAND -Wno-gnu -Wgnu-conditional-omitted-operand
// %clang_cc1 -fsyntax-only -verify %s -DEMPTYINIT -Wno-gnu -Wgnu-empty-initializer
// %clang_cc1 -fsyntax-only -verify %s -DLABELVALUE -Wno-gnu -Wgnu-label-as-value
// %clang_cc1 -fsyntax-only -verify %s -DSTATEMENTEXP -Wno-gnu -Wgnu-statement-expression
// %clang_cc1 -fsyntax-only -verify %s -DCOMPOUNDLITERALINITIALIZER -Wno-gnu -Wgnu-compound-literal-initializer
// %clang_cc1 -fsyntax-only -verify %s -DFLEXIBLEARRAYINITIALIZER -Wno-gnu -Wgnu-flexible-array-initializer
// %clang_cc1 -fsyntax-only -verify %s -DREDECLAREDENUM -Wno-gnu -Wgnu-redeclared-enum
// %clang_cc1 -fsyntax-only -verify %s -DUNIONCAST -Wno-gnu -Wgnu-union-cast
// %clang_cc1 -fsyntax-only -verify %s -DVARIABLESIZEDTYPENOTATEND -Wno-gnu -Wgnu-variable-sized-type-not-at-end
// %clang_cc1 -fsyntax-only -verify %s -DFOLDINGCONSTANT -Wno-gnu -Wgnu-folding-constant
// %clang_cc1 -fsyntax-only -verify %s -DEMPTYSTRUCT -Wno-gnu -Wgnu-empty-struct
#if NONE
// expected-no-diagnostics
#endif
#if ALL || ALIGNOF
// expected-warning@+4 {{'_Alignof' applied to an expression is a GNU extension}}
#endif
char align;
_Static_assert(_Alignof(align) > 0, "align's alignment is wrong");
#if ALL || CASERANGE
// expected-warning@+5 {{use of GNU case range extension}}
#endif
void caserange(int x) {
switch (x) {
case 42 ... 44: ;
}
}
#if ALL || COMPLEXINT
// expected-warning@+3 {{complex integer types are a GNU extension}}
#endif
_Complex short int complexint;
#if ALL || OMITTEDOPERAND
// expected-warning@+3 {{use of GNU ?: conditional expression extension, omitting middle operand}}
#endif
static const char* omittedoperand = (const char*)0 ?: "Null";
#if ALL || EMPTYINIT
// expected-warning@+3 {{use of GNU empty initializer extension}}
#endif
struct { int x; } emptyinit = {};
#if ALL || LABELVALUE
// expected-warning@+6 {{use of GNU address-of-label extension}}
// expected-warning@+7 {{use of GNU indirect-goto extension}}
#endif
void labelvalue() {
void *ptr;
ptr = &&foo;
foo:
goto *ptr;
}
#if ALL || STATEMENTEXP
// expected-warning@+5 {{use of GNU statement expression extension}}
#endif
void statementexp()
{
int a = ({ 1; });
}
#if ALL || COMPOUNDLITERALINITIALIZER
// expected-warning@+4 {{initialization of an array of type 'int [5]' from a compound literal of type 'int [5]' is a GNU extension}}
#endif
typedef int int5[5];
int cli[5] = (int[]){1, 2, 3, 4, 5};
#if ALL || FLEXIBLEARRAYINITIALIZER
// expected-note@+6 {{initialized flexible array member 'y' is here}}
// expected-warning@+6 {{flexible array initialization is a GNU extension}}
#endif
struct fai {
int x;
int y[];
} fai = { 1, { 2, 3, 4 } };
#if ALL || FOLDINGCONSTANT
// expected-warning@+5 {{expression is not an integer constant expression; folding it to a constant is a GNU extension}}
// expected-warning@+7 {{variable length array folded to constant array as an extension}}
#endif
enum {
fic = (int)(0.75 * 1000 * 1000)
};
static const int size = 100;
int data[size];
void foo(void) { int data[size]; } // OK, always a VLA
#if ALL || REDECLAREDENUM
// expected-note@+4 {{previous definition is here}}
// expected-warning@+8 {{redeclaration of already-defined enum 'RE' is a GNU extension}}
#endif
enum RE {
Val1,
Val2
};
enum RE;
#if ALL || UNIONCAST
// expected-warning@+4 {{cast to union type is a GNU extension}}
#endif
union uc { int i; unsigned : 3; };
union uc w = (union uc)2;
#if ALL || VARIABLESIZEDTYPENOTATEND
// expected-warning@+8 {{field 'hdr' with variable sized type 'struct vst' not at the end of a struct or class is a GNU extension}}
#endif
struct vst {
short tag_type;
char tag_data[];
};
struct vstnae {
struct vst hdr;
char data;
};
#if ALL || EMPTYSTRUCT
// expected-warning@+4 {{empty struct is a GNU extension}}
// expected-warning@+4 {{struct without named members is a GNU extension}}
#endif
const struct {} es;
struct {int:5;} swnm;