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c89 does not perform array -> pointer promotion unless the array is an lvalue. This 

is different than C99.  This fixes the rest of rdar://6095180.

llvm-svn: 54064
This commit is contained in:
Chris Lattner 2008-07-25 21:33:13 +00:00
parent 513165ecf3
commit 61f60a05b2
3 changed files with 34 additions and 8 deletions
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12
clang/lib/Sema/SemaExpr.cpp
View File

@ -58,8 +58,16 @@ void Sema::DefaultFunctionArrayConversion(Expr *&E) {
}
if (Ty->isFunctionType())
ImpCastExprToType(E, Context.getPointerType(Ty));
else if (Ty->isArrayType())
ImpCastExprToType(E, Context.getArrayDecayedType(Ty));
else if (Ty->isArrayType()) {
// In C90 mode, arrays only promote to pointers if the array expression is
// an lvalue. The relevant legalese is C90 6.2.2.1p3: "an lvalue that has
// type 'array of type' is converted to an expression that has type 'pointer
// to type'...". In C99 this was changed to: C99 6.3.2.1p3: "an expression
// that has type 'array of type' ...". The relevant change is "an lvalue"
// (C90) to "an expression" (C99).
if (getLangOptions().C99 || E->isLvalue() == Expr::LV_Valid)
ImpCastExprToType(E, Context.getArrayDecayedType(Ty));
}
}
/// UsualUnaryConversions - Performs various conversions that are common to most

18
clang/test/Sema/expr-comma-c89.c Normal file
View File

@ -0,0 +1,18 @@
// RUN: clang %s -fsyntax-only -verify -std=c99
// rdar://6095180
#include <assert.h>
struct s { char c[17]; };
extern struct s foo(void);
struct s a, b, c;
int A[sizeof((foo().c)) == 17 ? 1 : -1];
int B[sizeof((a.c)) == 17 ? 1 : -1];
// comma does array/function promotion in c99.
int X[sizeof(0, (foo().c)) == sizeof(char*) ? 1 : -1];
int Y[sizeof(0, (a,b).c) == sizeof(char*) ? 1 : -1];
int Z[sizeof(0, (a=b).c) == sizeof(char*) ? 1 : -1];

12
clang/test/Sema/expr-comma.c
View File

@ -1,4 +1,4 @@
// RUN: clang %s -fsyntax-only -verify -std=c99
// RUN: clang %s -fsyntax-only -verify -std=c89
// rdar://6095180
#include <assert.h>
@ -11,8 +11,8 @@ int A[sizeof((foo().c)) == 17 ? 1 : -1];
int B[sizeof((a.c)) == 17 ? 1 : -1];
// comma does array/function promotion in c99.
int X[sizeof(0, (foo().c)) == sizeof(char*) ? 1 : -1];
int Y[sizeof(0, (a,b).c) == sizeof(char*) ? 1 : -1];
int Z[sizeof(0, (a=b).c) == sizeof(char*) ? 1 : -1];
// comma does not promote array/function in c90 unless they are lvalues.
int W[sizeof(0, a.c) == sizeof(char*) ? 1 : -1];
int X[sizeof(0, (foo().c)) == 17 ? 1 : -1];
int Y[sizeof(0, (a,b).c) == 17 ? 1 : -1];
int Z[sizeof(0, (a=b).c) == 17 ? 1 : -1];