Implement GCC's -Wint-to-pointer-cast.

This implementation doesn't warn on anything that GCC doesn't warn on with the
exception of templates specializations (GCC doesn't warn, Clang does). The
specific skipped cases (boolean, constant expressions, enums) are open for
debate/adjustment if anyone wants to demonstrate that GCC is being overly
conservative here. The only really obvious false positive I found was in the
Clang regression suite's MPI test - apparently MPI uses specific flag values in
pointer constants. (eg: #define FOO (void*)~0)

llvm-svn: 166039

3 files changed, 14 insertions, 5 deletions

diff --git a/clang/test/Sema/block-return.c b/clang/test/Sema/block-return.c
index 6967955b087..2ea4d813ab0 100644
--- a/clang/test/Sema/block-return.c
+++ b/clang/test/Sema/block-return.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -pedantic -fsyntax-only %s -verify -fblocks
+// RUN: %clang_cc1 -Wno-int-to-pointer-cast -pedantic -fsyntax-only %s -verify -fblocks
 
 typedef void (^CL)(void);
 
diff --git a/clang/test/Sema/cast.c b/clang/test/Sema/cast.c
index 71c44b4b816..25ef1d03a4f 100644
--- a/clang/test/Sema/cast.c
+++ b/clang/test/Sema/cast.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only %s -verify
+// RUN: %clang_cc1 -fsyntax-only -triple x86_64-unknown-unknown %s -verify
 
 typedef struct { unsigned long bits[(((1) + (64) - 1) / (64))]; } cpumask_t;
 cpumask_t x;
@@ -52,8 +52,8 @@ void testInt(Int v) {
   (void) (CLong) v;
   (void) (CFloat) v;
   (void) (CDouble) v;
-  (void) (VoidPtr) v;
-  (void) (CharPtr) v;
+  (void) (VoidPtr) v; // expected-warning{{cast to 'VoidPtr' (aka 'void *') from smaller integer type 'Int' (aka 'int')}}
+  (void) (CharPtr) v; // expected-warning{{cast to 'CharPtr' (aka 'char *') from smaller integer type 'Int' (aka 'int')}}
 }
 
 void testLong(Long v) {
@@ -157,3 +157,12 @@ void testCharPtr(CharPtr v) {
   (void) (VoidPtr) v;
   (void) (CharPtr) v;
 }
+
+typedef enum { x_a, x_b } X;
+void *intToPointerCast2(X x) {
+  return (void*)x;
+}
+
+void *intToPointerCast3() {
+  return (void*)(1 + 3);
+}
diff --git a/clang/test/Sema/i-c-e.c b/clang/test/Sema/i-c-e.c
index ee61ac34a81..e7b42c4e9a1 100644
--- a/clang/test/Sema/i-c-e.c
+++ b/clang/test/Sema/i-c-e.c
@@ -1,4 +1,4 @@
-// RUN: %clang %s -ffreestanding -fsyntax-only -Xclang -verify -pedantic -fpascal-strings -std=c99
+// RUN: %clang %s -ffreestanding -Wno-int-to-pointer-cast -fsyntax-only -Xclang -verify -pedantic -fpascal-strings -std=c99
 
 #include <stdint.h>
 #include <limits.h>