[Sema] Fix pointer-to-int-cast diagnostic for _Bool

[Mordante]

Summary

The diagnostic added in D72231 also shows a diagnostic when casting to a _Bool. This is unwanted. This patch removes the diagnostic for _Bool.

[rjmccall]

Can we test the same thing in C++?

[nickdesaulniers]

Also, make sure to run git-clang-format HEAD~ on the patch, as the linter suggests. Thanks for the patch.

[Mordante]

In D74860#1883415, @rjmccall wrote:

Can we test the same thing in C++?

I'll add some tests, but C++ uses a different codepath for c-style casts.

In D74860#1883480, @nickdesaulniers wrote:

Also, make sure to run git-clang-format HEAD~ on the patch, as the linter suggests. Thanks for the patch.

I'd rather not run it on the tests. The new code uses the same style as the surrounding code. If wanted I can run the formatter on the changed test files and commit them separately.

[Mordante]

Added some C++ tests for similar c-style casts.

[rjmccall]

In D74860#1888024, @Mordante wrote:

In D74860#1883415, @rjmccall wrote:

Can we test the same thing in C++?

I'll add some tests, but C++ uses a different codepath for c-style casts.

Since the warning applies in both modes, we generally need to be testing all the cases in both. The implementation being significantly different is a *better* reason to do this.

Anyway, thanks, LGTM.

clang/lib/Sema/SemaCast.cpp

if (!DestType->isIntegralType(Self.Context) &&
       Self.Diag(SrcExpr.get()->getBeginLoc(),
                 diag::err_cast_pointer_to_non_pointer_int)
           << DestType << SrcExpr.get()->getSourceRange();
       SrcExpr = ExprError();
       return;
     }
 
     if ((Self.Context.getTypeSize(SrcType) >
-         Self.Context.getTypeSize(DestType))) {
+         Self.Context.getTypeSize(DestType)) &&
+        !DestType->isBooleanType()) {
       // C 6.3.2.3p6: Any pointer type may be converted to an integer type.
       // Except as previously specified, the result is implementation-defined.
       // If the result cannot be represented in the integer type, the behavior
       // is undefined. The result need not be in the range of values of any
       // integer type.
       unsigned Diag = Self.getLangOpts().MicrosoftExt
                           ? diag::ext_ms_pointer_to_int_cast
                           : SrcType->isVoidPointerType()

clang/test/Sema/MicrosoftExtensions.c

 
 void pointer_to_integral_type_conv(char* ptr) {
    char ch = (char)ptr; // expected-warning{{cast to smaller integer type 'char' from 'char *' is a Microsoft extension}}
    short sh = (short)ptr; // expected-warning{{cast to smaller integer type 'short' from 'char *' is a Microsoft extension}}
    ch = (char)ptr; // expected-warning{{cast to smaller integer type 'char' from 'char *' is a Microsoft extension}}
    sh = (short)ptr; // expected-warning{{cast to smaller integer type 'short' from 'char *' is a Microsoft extension}}
 
    // This is valid ISO C.
-   _Bool b = (_Bool)ptr; // expected-warning{{cast to smaller integer type '_Bool' from 'char *' is a Microsoft extension}}
+   _Bool b = (_Bool)ptr;
 }
 
 typedef struct {
   UNKNOWN u; // expected-error {{unknown type name 'UNKNOWN'}}
 } AA;
 
 typedef struct {
   AA; // expected-warning {{anonymous structs are a Microsoft extension}}

clang/test/Sema/cast.c

void testCDouble(CDouble v) {
   (void) (Double) v;
   (void) (CInt) v;
   (void) (CLong) v;
   (void) (CFloat) v;
   (void) (CDouble) v;
 }
 
 void testVoidPtr(VoidPtr v) {
-  (void) (Bool) v; // expected-warning{{cast to smaller integer type 'Bool' (aka '_Bool') from 'VoidPtr' (aka 'void *')}}
+  (void)(Bool) v;
   (void) (Int) v; // expected-warning{{cast to smaller integer type 'Int' (aka 'int') from 'VoidPtr' (aka 'void *')}}
   (void) (Long) v;
   (void) (VoidPtr) v;
   (void) (CharPtr) v;
   // Test that casts to void* can be controlled separately
   // from other -Wpointer-to-int-cast warnings.
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wvoid-pointer-to-int-cast"
-  (void) (Bool) v; // no-warning
+  (void)(Int) v; // no-warning
 #pragma clang diagnostic pop
 }
 
 void testCharPtr(CharPtr v) {
-  (void) (Bool) v; // expected-warning{{cast to smaller integer type 'Bool' (aka '_Bool') from 'CharPtr' (aka 'char *')}}
+  (void)(Bool) v;
   (void) (Int) v; // expected-warning{{cast to smaller integer type 'Int' (aka 'int') from 'CharPtr' (aka 'char *')}}
   (void) (Long) v;
   (void) (VoidPtr) v;
   (void) (CharPtr) v;
   // Test that casts to void* can be controlled separately
   // from other -Wpointer-to-int-cast warnings.
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wvoid-pointer-to-int-cast"
-  (void) (Bool) v; // expected-warning{{cast to smaller integer type 'Bool' (aka '_Bool') from 'CharPtr' (aka 'char *')}}
+  (void)(Int) v; // expected-warning{{cast to smaller integer type 'Int' (aka 'int') from 'CharPtr' (aka 'char *')}}
 #pragma clang diagnostic pop
 }
 
 typedef enum { x_a, x_b } X;
 void *intToPointerCast2(X x) {
   return (void*)x;
 }
 
 void *intToPointerCast3() {
   return (void*)(1 + 3);
 }

clang/test/SemaCXX/cstyle-cast.cpp

 void integral_conversion()
 {
   void *vp = (void*)(testval);
   long l = (long)(vp);
   (void)(float*)(l);
   fnptr fnp = (fnptr)(l);
   (void)(char)(fnp); // expected-error {{cast from pointer to smaller type 'char' loses information}}
   (void)(long)(fnp);
+
+  (void)(bool)((void*)0);
+  (void)(bool)((int*)0);
+  (void)(char)((void*)0); // expected-error {{cast from pointer to smaller type 'char' loses information}}
+  (void)(char)((int*)0);  // expected-error {{cast from pointer to smaller type 'char' loses information}}
 }
 
 void pointer_conversion()
 {
   int *p1 = 0;
   float *p2 = (float*)(p1);
   structure *p3 = (structure*)(p2);
   typedef int **ppint;