[cfe-commits] r132983 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaType.cpp test/Sema/const-eval.c test/Sema/i-c-e.c test/Sema/struct-decl.c test/Sema/typedef-variable-type.c test/Sema/vla.c test/SemaCXX/c99-variable-length-array.cpp
Chris Lattner
sabre at nondot.org
Mon Jun 13 23:38:11 PDT 2011
Author: lattner
Date: Tue Jun 14 01:38:10 2011
New Revision: 132983
URL: http://llvm.org/viewvc/llvm-project?rev=132983&view=rev
Log:
when compiling in a GNU mode (e.g. gnu99) treat VLAs with a size that can be folded to a constant
as constant size arrays. This has slightly different semantics in some insane cases, but allows
us to accept some constructs that GCC does. Continue to be pedantic in -std=c99 and other
modes. This addressed rdar://8733881 - error "variable-sized object may not be initialized"; g++ accepts same code
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaType.cpp
cfe/trunk/test/Sema/const-eval.c
cfe/trunk/test/Sema/i-c-e.c
cfe/trunk/test/Sema/struct-decl.c
cfe/trunk/test/Sema/typedef-variable-type.c
cfe/trunk/test/Sema/vla.c
cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Jun 14 01:38:10 2011
@@ -48,6 +48,8 @@
"variable length array declaration can not have 'static' storage duration">;
def err_vla_decl_has_extern_linkage : Error<
"variable length array declaration can not have 'extern' linkage">;
+def ext_vla_folded_to_constant : Extension<
+ "variable length array folded to constant array as an extension">;
// C99 variably modified types
def err_variably_modified_template_arg : Error<
Modified: cfe/trunk/lib/Sema/SemaType.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaType.cpp?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaType.cpp (original)
+++ cfe/trunk/lib/Sema/SemaType.cpp Tue Jun 14 01:38:10 2011
@@ -1100,6 +1100,28 @@
return Context.getRValueReferenceType(T);
}
+/// Check whether the specified array size makes the array type a VLA. If so,
+/// return true, if not, return the size of the array in SizeVal.
+static bool isArraySizeVLA(Expr *ArraySize, llvm::APSInt &SizeVal, Sema &S) {
+ // If the size is an ICE, it certainly isn't a VLA.
+ if (ArraySize->isIntegerConstantExpr(SizeVal, S.Context))
+ return false;
+
+ // If we're in a GNU mode (like gnu99, but not c99) accept any evaluatable
+ // value as an extension.
+ Expr::EvalResult Result;
+ if (S.LangOpts.GNUMode && ArraySize->Evaluate(Result, S.Context)) {
+ if (!Result.hasSideEffects() && Result.Val.isInt()) {
+ SizeVal = Result.Val.getInt();
+ S.Diag(ArraySize->getLocStart(), diag::ext_vla_folded_to_constant);
+ return false;
+ }
+ }
+
+ return true;
+}
+
+
/// \brief Build an array type.
///
/// \param T The type of each element in the array.
@@ -1200,11 +1222,13 @@
T = Context.getIncompleteArrayType(T, ASM, Quals);
} else if (ArraySize->isTypeDependent() || ArraySize->isValueDependent()) {
T = Context.getDependentSizedArrayType(T, ArraySize, ASM, Quals, Brackets);
- } else if (!ArraySize->isIntegerConstantExpr(ConstVal, Context) ||
- (!T->isDependentType() && !T->isIncompleteType() &&
- !T->isConstantSizeType())) {
- // Per C99, a variable array is an array with either a non-constant
- // size or an element type that has a non-constant-size
+ } else if (!T->isDependentType() && !T->isIncompleteType() &&
+ !T->isConstantSizeType()) {
+ // C99: an array with an element type that has a non-constant-size is a VLA.
+ T = Context.getVariableArrayType(T, ArraySize, ASM, Quals, Brackets);
+ } else if (isArraySizeVLA(ArraySize, ConstVal, *this)) {
+ // C99: an array with a non-ICE size is a VLA. We accept any expression
+ // that we can fold to a non-zero positive value as an extension.
T = Context.getVariableArrayType(T, ArraySize, ASM, Quals, Brackets);
} else {
// C99 6.7.5.2p1: If the expression is a constant expression, it shall
Modified: cfe/trunk/test/Sema/const-eval.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/const-eval.c?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/test/Sema/const-eval.c (original)
+++ cfe/trunk/test/Sema/const-eval.c Tue Jun 14 01:38:10 2011
@@ -36,7 +36,7 @@
EVAL_EXPR(18, ((int)((void*)10 + 10)) == 20 ? 1 : -1);
struct s {
- int a[(int)-1.0f]; // expected-error {{array size is negative}}
+ int a[(int)-1.0f]; // expected-error {{'a' declared as an array with a negative size}}
};
EVAL_EXPR(19, ((int)&*(char*)10 == 10 ? 1 : -1));
Modified: cfe/trunk/test/Sema/i-c-e.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/i-c-e.c?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/test/Sema/i-c-e.c (original)
+++ cfe/trunk/test/Sema/i-c-e.c Tue Jun 14 01:38:10 2011
@@ -1,4 +1,4 @@
-// RUN: %clang %s -ffreestanding -fsyntax-only -Xclang -verify -pedantic -fpascal-strings
+// RUN: %clang %s -ffreestanding -fsyntax-only -Xclang -verify -pedantic -fpascal-strings -std=c99
#include <stdint.h>
#include <limits.h>
Modified: cfe/trunk/test/Sema/struct-decl.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/struct-decl.c?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/test/Sema/struct-decl.c (original)
+++ cfe/trunk/test/Sema/struct-decl.c Tue Jun 14 01:38:10 2011
@@ -6,7 +6,7 @@
struct foo {
char name[(int)&((struct bar *)0)->n];
- char name2[(int)&((struct bar *)0)->n - 1]; //expected-error{{array size is negative}}
+ char name2[(int)&((struct bar *)0)->n - 1]; //expected-error{{'name2' declared as an array with a negative size}}
};
// PR3430
Modified: cfe/trunk/test/Sema/typedef-variable-type.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/typedef-variable-type.c?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/test/Sema/typedef-variable-type.c (original)
+++ cfe/trunk/test/Sema/typedef-variable-type.c Tue Jun 14 01:38:10 2011
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -verify -fsyntax-only -pedantic -Wno-typedef-redefinition
+// RUN: %clang_cc1 %s -verify -fsyntax-only -pedantic -Wno-typedef-redefinition -std=c99
// Make sure we accept a single typedef
typedef int (*a)[!.0]; // expected-warning{{size of static array must be an integer constant expression}}
Modified: cfe/trunk/test/Sema/vla.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/vla.c?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/test/Sema/vla.c (original)
+++ cfe/trunk/test/Sema/vla.c Tue Jun 14 01:38:10 2011
@@ -42,7 +42,7 @@
}
// PR3663
-static const unsigned array[((2 * (int)((((4) / 2) + 1.0/3.0) * (4) - 1e-8)) + 1)]; // expected-warning {{size of static array must be an integer constant expression}}
+static const unsigned array[((2 * (int)((((4) / 2) + 1.0/3.0) * (4) - 1e-8)) + 1)]; // expected-warning {{variable length array folded to constant array as an extension}}
int a[*]; // expected-error {{star modifier used outside of function prototype}}
int f4(int a[*][*]);
@@ -53,7 +53,7 @@
int (*pr2044c(void))[pr2044b]; // expected-error {{variably modified type}}
const int f5_ci = 1;
-void f5() { char a[][f5_ci] = {""}; } // expected-error {{variable-sized object may not be initialized}}
+void f5() { char a[][f5_ci] = {""}; } // expected-warning {{variable length array folded to constant array as an extension}}
// PR5185
void pr5185(int a[*]);
Modified: cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp?rev=132983&r1=132982&r2=132983&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp (original)
+++ cfe/trunk/test/SemaCXX/c99-variable-length-array.cpp Tue Jun 14 01:38:10 2011
@@ -121,3 +121,12 @@
(void)new vla_type; // expected-error{{variably}}
}
}
+
+namespace rdar8733881 { // rdar://8733881
+
+static const int k_cVal3 = (int)(1000*0.2f);
+ int f() {
+ // Ok, fold to a constant size array as an extension.
+ char rgch[k_cVal3] = {0};
+ }
+}
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