[Clang] [Sema] Make -Wincompatible-pointer-types an error by default

clang/docs/ReleaseNotes.rst

@@ -58,6 +58,9 @@ C/C++ Language Potentially Breaking Changes
 
 - The ``__has_builtin`` function now only considers the currently active target when being used with target offloading.
 
+- The ``-Wincompatible-pointer-types`` diagnostic now defaults to an error;
+  it can still be downgraded to a warning by passing ``-Wno-error=incompatible-pointer-types``.
+
 C++ Specific Potentially Breaking Changes
 -----------------------------------------
 - For C++20 modules, the Reduced BMI mode will be the default option. This may introduce

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -9048,7 +9048,7 @@ def ext_typecheck_convert_incompatible_pointer : ExtWarn<
   "; take the address with &|"
   "; remove *|"
   "; remove &}3">,
-  InGroup<IncompatiblePointerTypes>;
+  InGroup<IncompatiblePointerTypes>, DefaultError;
 def err_typecheck_convert_incompatible_pointer : Error<
   "incompatible pointer types "
   "%select{%diff{assigning to $ from $|assigning to different types}0,1"

clang/test/APINotes/nullability.c

@@ -15,7 +15,7 @@ int main() {
 
   take_pointer_and_int(0, 0); // expected-warning{{null passed to a callee that requires a non-null argument}}
 
-  float *fp = global_int; // expected-warning{{incompatible pointer types initializing 'float *' with an expression of type 'int * _Nonnull'}}
+  float *fp = global_int; // expected-error{{incompatible pointer types initializing 'float *' with an expression of type 'int * _Nonnull'}}
   return 0;
 }
 

clang/test/APINotes/nullability.m

@@ -11,10 +11,10 @@ int main() {
   A *a;
 
 #if SWIFT_VERSION_3_0
-  float *fp =  // expected-warning{{incompatible pointer types initializing 'float *' with an expression of type 'A * _Nullable'}}
+  float *fp =  // expected-error{{incompatible pointer types initializing 'float *' with an expression of type 'A * _Nullable'}}
     [a transform: 0 integer: 0];
 #else
-  float *fp =  // expected-warning{{incompatible pointer types initializing 'float *' with an expression of type 'A *'}}
+  float *fp =  // expected-error{{incompatible pointer types initializing 'float *' with an expression of type 'A *'}}
     [a transform: 0 integer: 0]; // expected-warning{{null passed to a callee that requires a non-null argument}}
 #endif
 

clang/test/APINotes/types.m

@@ -12,17 +12,17 @@
 // CHECK-NEXT: } AnonEnumWithTypedefName
 
 void test(OverriddenTypes *overridden) {
-  int *ip1 = global_int_ptr; // expected-warning{{incompatible pointer types initializing 'int *' with an expression of type 'double (*)(int, int)'}}
+  int *ip1 = global_int_ptr; // expected-error{{incompatible pointer types initializing 'int *' with an expression of type 'double (*)(int, int)'}}
 
-  int *ip2 = global_int_fun( // expected-warning{{incompatible pointer types initializing 'int *' with an expression of type 'char *'}}
-               ip2, // expected-warning{{incompatible pointer types passing 'int *' to parameter of type 'double *'}}
-               ip2); // expected-warning{{incompatible pointer types passing 'int *' to parameter of type 'float *'}}
+  int *ip2 = global_int_fun( // expected-error{{incompatible pointer types initializing 'int *' with an expression of type 'char *'}}
+               ip2, // expected-error{{incompatible pointer types passing 'int *' to parameter of type 'double *'}}
+               ip2); // expected-error{{incompatible pointer types passing 'int *' to parameter of type 'float *'}}
 
-  int *ip3 = [overridden // expected-warning{{incompatible pointer types initializing 'int *' with an expression of type 'char *'}}
-                methodToMangle: ip3 // expected-warning{{incompatible pointer types sending 'int *' to parameter of type 'double *'}}
-                        second: ip3]; // expected-warning{{incompatible pointer types sending 'int *' to parameter of type 'float *'}}
+  int *ip3 = [overridden // expected-error{{incompatible pointer types initializing 'int *' with an expression of type 'char *'}}
+                methodToMangle: ip3 // expected-error{{incompatible pointer types sending 'int *' to parameter of type 'double *'}}
+                        second: ip3]; // expected-error{{incompatible pointer types sending 'int *' to parameter of type 'float *'}}
 
-  int *ip4 = overridden.intPropertyToMangle; // expected-warning{{incompatible pointer types initializing 'int *' with an expression of type 'double *'}}
+  int *ip4 = overridden.intPropertyToMangle; // expected-error{{incompatible pointer types initializing 'int *' with an expression of type 'double *'}}
 }
 
 // expected-note@SomeKit/SomeKit.h:42{{passing argument to parameter 'ptr' here}}

clang/test/AST/ByteCode/atomic.c

@@ -8,8 +8,8 @@ _Atomic int ai = 0;
 // FIXME: &ai is an address constant, so this should be accepted as an
 // initializer, but the bit-cast inserted due to the pointer conversion is
 // tripping up the test for whether the initializer is a constant expression.
-// The warning is correct but the error is not.
-_Atomic(int *) aip3 = &ai; // both-warning {{incompatible pointer types initializing '_Atomic(int *)' with an expression of type '_Atomic(int) *'}} \
+// The first error is correct; the second is not.
+_Atomic(int *) aip3 = &ai; // both-error {{incompatible pointer types initializing '_Atomic(int *)' with an expression of type '_Atomic(int) *'}} \
                            // both-error {{initializer element is not a compile-time constant}}
 
 #include <stdatomic.h>

clang/test/AST/ByteCode/c.c

@@ -349,7 +349,7 @@ const unsigned char _str2[] = {S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7]};
 const int compared = strcmp(_str, (const char *)_str2); // all-error {{initializer element is not a compile-time constant}}
 
 
-const int compared2 = strcmp(strcmp, _str); // all-warning {{incompatible pointer types}} \
+const int compared2 = strcmp(strcmp, _str); // all-error {{incompatible pointer types}} \
                                             // all-error {{initializer element is not a compile-time constant}}
 
 int foo(x) // all-warning {{a function definition without a prototype is deprecated in all versions of C}}

clang/test/Analysis/OSAtomic_mac.c

@@ -15,7 +15,7 @@ int *invalidSLocOnRedecl(void) {
   // something like "The "compare" part of CompareAndSwap depends on an
   // undefined value".
   int *b;
-  OSAtomicCompareAndSwapPtrBarrier(0, 0, &b); // no-crash
+  OSAtomicCompareAndSwapPtrBarrier(0, 0, (void**)&b); // no-crash
   return b;
 }
 

clang/test/Analysis/bsd-string.c

@@ -137,5 +137,5 @@ void f11(void) {
 int a, b;
 void unknown_val_crash(void) {
   // We're unable to evaluate the integer-to-pointer cast.
-  strlcat(&b, a, 0); // no-crash
+  strlcat((char*)&b, a, 0); // no-crash
 }

clang/test/Analysis/novoidtypecrash.c

@@ -3,7 +3,7 @@ x;
 y(void **z) { // no-crash
   *z = x;
   int *w;
-  y(&w);
+  y((void**)&w);
   *w;
 }
 

clang/test/Analysis/override-werror.c

@@ -5,9 +5,9 @@
 // -Werror.  This allows basic warnings not to interfere with producing
 // analyzer results.
 
-char* f(int *p) {
-  return p; // expected-warning{{incompatible pointer types}} \
-               werror-warning{{incompatible pointer types}}
+void f(int *p) {
+  int; // expected-warning{{declaration does not declare anything}} \
+          werror-warning{{declaration does not declare anything}}
 }
 
 void g(int *p) {

clang/test/Analysis/uninit-vals-union.c

@@ -1,4 +1,5 @@
 // RUN: %clang_analyze_cc1 -analyzer-checker=core.builtin -verify -Wno-unused %s
+// expected-no-diagnostics
 
 typedef union {
   int y;
@@ -8,6 +9,6 @@ typedef struct { int x; } A;
 
 void foo(void) {
   U u = {};
-  A *a = &u; // expected-warning{{incompatible pointer types}}
+  A *a = (A*)&u;
   a->x;      // no-crash
 }

clang/test/C/C23/n3007.c

@@ -13,7 +13,7 @@ void test_qualifiers(int x, const int y, int * restrict z) {
   static auto c = 1UL;
   int* pa = &a; // expected-warning {{initializing 'int *' with an expression of type 'const int *' discards qualifiers}}
   const int* pb = &b;
-  int* pc = &c; // expected-warning {{incompatible pointer types initializing 'int *' with an expression of type 'unsigned long *'}}
+  int* pc = &c; // expected-error {{incompatible pointer types initializing 'int *' with an expression of type 'unsigned long *'}}
 
   const int ci = 12;
   auto yup = ci;

clang/test/C/C2y/n3369.c

@@ -100,11 +100,11 @@ void test_funcs() {
   int i5[5];
   char c35[3][5];
   test_func_fix_fix(5, &c35, &i3, NULL);
-  test_func_fix_fix(5, &c35, &i5, NULL); // expected-warning {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
+  test_func_fix_fix(5, &c35, &i5, NULL); // expected-error {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
   test_func_fix_var(5, &c35, &i3, NULL);
-  test_func_fix_var(5, &c35, &i5, NULL); // expected-warning {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
+  test_func_fix_var(5, &c35, &i5, NULL); // expected-error {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
   test_func_fix_uns(5, &c35, &i3, NULL);
-  test_func_fix_uns(5, &c35, &i5, NULL); // expected-warning {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
+  test_func_fix_uns(5, &c35, &i5, NULL); // expected-error {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
 }
 
 void test_multidimensional_arrays() {

clang/test/C/drs/dr0xx.c

@@ -459,7 +459,7 @@ void dr088_1(void) {
   /* Distinct type from the file scope forward declaration. */
   struct dr088_t_1;
   /* FIXME: this diagnostic could be improved to not be utterly baffling. */
-  dr088_f((struct dr088_t_1 *)0); /* expected-warning {{incompatible pointer types passing 'struct dr088_t_1 *' to parameter of type 'struct dr088_t_1 *'}} */
+  dr088_f((struct dr088_t_1 *)0); /* expected-error {{incompatible pointer types passing 'struct dr088_t_1 *' to parameter of type 'struct dr088_t_1 *'}} */
 }
 
 void dr088_2(struct dr088_t_1 *p) { /* Pointer to incomplete type. */ }

clang/test/CodeGen/2008-03-05-syncPtr.c

@@ -34,7 +34,7 @@ int* foo5(int** a, int* b) {
 
 
 int* foo6(int** a, int*** b) {
-  return __sync_lock_test_and_set (a, b);
+  return __sync_lock_test_and_set (a, (int*)b);
 }
 // CHECK-LABEL: define{{.*}} ptr @foo6
 // CHECK: atomicrmw xchg {{.*}}, align 8

clang/test/CodeGen/X86/cmpccxadd-builtins-error.c

@@ -12,5 +12,5 @@ long long test_cmpccxadd64(void *__A, long long __B, long long __C) {
 }
 
 long long test_cmpccxadd64_2(int *__A, long long __B, long long __C) {
-  return _cmpccxadd_epi64(__A, __B, __C, 3); // expected-warning {{incompatible pointer types passing 'int *' to parameter of type 'long long *'}}
+  return _cmpccxadd_epi64(__A, __B, __C, 3); // expected-error {{incompatible pointer types passing 'int *' to parameter of type 'long long *'}}
 }

clang/test/CodeGen/X86/math-builtins.c

@@ -1,9 +1,9 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -w -o - -emit-llvm %s | FileCheck %s -check-prefix=NO__ERRNO
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -w -o - -emit-llvm -fmath-errno %s | FileCheck %s -check-prefix=HAS_ERRNO
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -w -o - -emit-llvm -disable-llvm-passes -O2 %s | FileCheck %s -check-prefix=NO__ERRNO
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -w -o - -emit-llvm -disable-llvm-passes -O2 -fmath-errno %s | FileCheck %s -check-prefix=HAS_ERRNO
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown-gnu -w -o - -emit-llvm -fmath-errno %s | FileCheck %s --check-prefix=HAS_ERRNO_GNU
-// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -w -o - -emit-llvm -fmath-errno %s | FileCheck %s --check-prefix=HAS_ERRNO_WIN
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -triple x86_64-unknown-unknown -w -o - -emit-llvm %s | FileCheck %s -check-prefix=NO__ERRNO
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -triple x86_64-unknown-unknown -w -o - -emit-llvm -fmath-errno %s | FileCheck %s -check-prefix=HAS_ERRNO
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -triple x86_64-unknown-unknown -w -o - -emit-llvm -disable-llvm-passes -O2 %s | FileCheck %s -check-prefix=NO__ERRNO
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -triple x86_64-unknown-unknown -w -o - -emit-llvm -disable-llvm-passes -O2 -fmath-errno %s | FileCheck %s -check-prefix=HAS_ERRNO
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -triple x86_64-unknown-unknown-gnu -w -o - -emit-llvm -fmath-errno %s | FileCheck %s --check-prefix=HAS_ERRNO_GNU
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -triple x86_64-unknown-windows-msvc -w -o - -emit-llvm -fmath-errno %s | FileCheck %s --check-prefix=HAS_ERRNO_WIN
 
 // Test attributes and codegen of math builtins.
 

clang/test/CodeGen/arm64-microsoft-intrinsics.c

@@ -4,14 +4,21 @@
 // RUN: not %clang_cc1 -triple arm64-linux -Werror -S -o /dev/null %s 2>&1 \
 // RUN:    | FileCheck %s -check-prefix CHECK-LINUX
 
-// RUN: %clang_cc1 -triple arm64-darwin -Wno-implicit-function-declaration -fms-compatibility -emit-llvm -o - %s \
+// RUN: %clang_cc1 -triple arm64-darwin -Wno-implicit-function-declaration -fms-compatibility -emit-llvm -o - -DARM64_DARWIN %s \
 // RUN:    | FileCheck %s -check-prefix CHECK-MSCOMPAT
 
-long test_InterlockedAdd(long volatile *Addend, long Value) {
+// For some reason '_InterlockedAdd` on arm64-darwin takes an 'int*' rather than a 'long*'.
+#ifdef ARM64_DARWIN
+typedef int int32_t;
+#else
+typedef long int32_t;
+#endif
+
+long test_InterlockedAdd(int32_t volatile *Addend, long Value) {
   return _InterlockedAdd(Addend, Value);
 }
 
-long test_InterlockedAdd_constant(long volatile *Addend) {
+long test_InterlockedAdd_constant(int32_t volatile *Addend) {
   return _InterlockedAdd(Addend, -1);
 }
 
@@ -21,7 +28,7 @@ long test_InterlockedAdd_constant(long volatile *Addend) {
 // CHECK-MSVC: ret i32 %[[NEWVAL:[0-9]+]]
 // CHECK-LINUX: error: call to undeclared function '_InterlockedAdd'
 
-long test_InterlockedAdd_acq(long volatile *Addend, long Value) {
+long test_InterlockedAdd_acq(int32_t volatile *Addend, long Value) {
   return _InterlockedAdd_acq(Addend, Value);
 }
 
@@ -31,7 +38,7 @@ long test_InterlockedAdd_acq(long volatile *Addend, long Value) {
 // CHECK-MSVC: ret i32 %[[NEWVAL:[0-9]+]]
 // CHECK-LINUX: error: call to undeclared function '_InterlockedAdd_acq'
 
-long test_InterlockedAdd_nf(long volatile *Addend, long Value) {
+long test_InterlockedAdd_nf(int32_t volatile *Addend, long Value) {
   return _InterlockedAdd_nf(Addend, Value);
 }
 
@@ -41,7 +48,7 @@ long test_InterlockedAdd_nf(long volatile *Addend, long Value) {
 // CHECK-MSVC: ret i32 %[[NEWVAL:[0-9]+]]
 // CHECK-LINUX: error: call to undeclared function '_InterlockedAdd_nf'
 
-long test_InterlockedAdd_rel(long volatile *Addend, long Value) {
+long test_InterlockedAdd_rel(int32_t volatile *Addend, long Value) {
   return _InterlockedAdd_rel(Addend, Value);
 }
 

clang/test/CodeGen/builtin-rename.c

@@ -4,5 +4,5 @@
 int printf(const char *, ...);
 
 int foo(void) {
-  return printf(printf);
+  return printf((const char*)printf);
 }

clang/test/CodeGen/ms-intrinsics-underaligned.c

@@ -111,6 +111,6 @@ long test_InterlockedAdd(X *x) {
 // CHECK-AARCH64-LABEL: @test_InterlockedAdd64(
 // CHECK-AARCH64:   atomicrmw {{.*}} align 8
 long test_InterlockedAdd64(X *x) {
-  return _InterlockedAdd64(&x->c, 4);
+  return _InterlockedAdd64((volatile long long*)&x->c, 4);
 }
 #endif

clang/test/CodeGen/ubsan-pass-object-size.c

@@ -14,7 +14,8 @@ int foo(int *const p __attribute__((pass_object_size(0))), int n) {
   // CHECK: __ubsan_handle_out_of_bounds
 
   {
-    int **p = &p; // Shadow the parameter. The pass_object_size info is lost.
+    int **q = &p;
+    int **p = q; // Shadow the parameter. The pass_object_size info is lost.
     // CHECK-NOT: __ubsan_handle_out_of_bounds
     x = *p[n];
   }

clang/test/CodeGen/vla.c

@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -Wno-int-conversion -triple i386-unknown-unknown %s -emit-llvm -o - | FileCheck %s -check-prefixes=CHECK,NULL-INVALID
-// RUN: %clang_cc1 -Wno-int-conversion -triple i386-unknown-unknown %s -emit-llvm -fno-delete-null-pointer-checks -o - | FileCheck %s -check-prefixes=CHECK,NULL-VALID
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -Wno-int-conversion -triple i386-unknown-unknown %s -emit-llvm -o - | FileCheck %s -check-prefixes=CHECK,NULL-INVALID
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types -Wno-int-conversion -triple i386-unknown-unknown %s -emit-llvm -fno-delete-null-pointer-checks -o - | FileCheck %s -check-prefixes=CHECK,NULL-VALID
 
 int b(char* x);
 

clang/test/CodeGen/vlt_to_pointer.c

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -Wno-error=incompatible-pointer-types %s -emit-llvm -o - | FileCheck %s
 
 int c[1][3*2];
 // CHECK: @{{.+}} ={{.*}}global [1 x [6 x {{i[0-9]+}}]] zeroinitializer

clang/test/FixIt/fixit-objc-arc.m

@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 -pedantic -verify %s
+// RUN: %clang_cc1 -pedantic -verify %s -Wno-error=incompatible-pointer-types
 // RUN: cp %s %t
-// RUN: not %clang_cc1 -pedantic -fobjc-arc -fixit -x objective-c %t
-// RUN: %clang_cc1 -pedantic -fobjc-arc -Werror -x objective-c %t
+// RUN: not %clang_cc1 -pedantic -fobjc-arc -fixit -x objective-c %t -Wno-error=incompatible-pointer-types
+// RUN: %clang_cc1 -pedantic -fobjc-arc -Werror -x objective-c %t -Wno-error=incompatible-pointer-types
 
 @class A;
 @class NSString;

clang/test/Frontend/fixed_point_unknown_conversions.c

@@ -26,11 +26,11 @@ void func(void) {
   accum = ic;      // expected-error{{conversion between fixed point and '_Complex int' is not yet supported}}
   accum = s;       // expected-error{{assigning to '_Accum' from incompatible type 'struct S'}}
   accum = ptr;     // expected-error{{assigning to '_Accum' from incompatible type 'int *'}}
-  accum_ptr = ptr; // expected-warning{{incompatible pointer types assigning to '_Accum *' from 'int *'}}
+  accum_ptr = ptr; // expected-error{{incompatible pointer types assigning to '_Accum *' from 'int *'}}
 
   dc = accum;      // expected-error{{conversion between fixed point and '_Complex double' is not yet supported}}
   ic = accum;      // expected-error{{conversion between fixed point and '_Complex int' is not yet supported}}
   s = accum;       // expected-error{{assigning to 'struct S' from incompatible type '_Accum'}}
   ptr = accum;     // expected-error{{assigning to 'int *' from incompatible type '_Accum'}}
-  ptr = accum_ptr; // expected-warning{{incompatible pointer types assigning to 'int *' from '_Accum *'}}
+  ptr = accum_ptr; // expected-error{{incompatible pointer types assigning to 'int *' from '_Accum *'}}
 }

clang/test/Index/preamble.c

@@ -21,7 +21,7 @@ void f(int x) {
 // CHECK: preamble.h:5:10: IntegerLiteral= Extent=[5:10 - 5:11]
 // CHECK: preamble.c:8:5: FunctionDecl=wibble:8:5 Extent=[8:1 - 8:16]
 // CHECK: preamble.c:8:15: ParmDecl=:8:15 (Definition) Extent=[8:12 - 8:15]
-// CHECK-DIAG: preamble.h:4:7:{4:9-4:13}: warning: incompatible pointer types assigning to 'int *' from 'float *'
+// CHECK-DIAG: preamble.h:4:7:{4:9-4:13}: error: incompatible pointer types assigning to 'int *' from 'float *'
 // FIXME: Should see:
 //     preamble.c:5:9: warning: macro is not used
 // CHECK-DIAG-NOT: preamble.c:6:9: warning: macro is not used

clang/test/Index/warning-flags.c

@@ -1,5 +1,5 @@
 int foo(void) { }
-int *bar(float *f) { return f; }
+void bar(void) { int; }
 
 // RUN: c-index-test -test-load-source all %s 2>&1|FileCheck -check-prefix=CHECK-BOTH-WARNINGS %s
 // RUN: c-index-test -test-load-source-reparse 5 all %s 2>&1|FileCheck -check-prefix=CHECK-BOTH-WARNINGS %s
@@ -10,9 +10,9 @@ int *bar(float *f) { return f; }
 // RUN: c-index-test -test-load-source all -w -O4 %s 2>&1 | FileCheck -check-prefix=NOWARNINGS %s
 
 // CHECK-BOTH-WARNINGS: warning: non-void function does not return a value
-// CHECK-BOTH-WARNINGS: warning: incompatible pointer types returning 'float *' from a function with result type 'int *'
+// CHECK-BOTH-WARNINGS: warning: declaration does not declare anything
 
 // CHECK-SECOND-WARNING-NOT:non-void function does not return a value
-// CHECK-SECOND-WARNING: warning: incompatible pointer types returning 'float *' from a function with result type 'int *'
+// CHECK-SECOND-WARNING: warning: declaration does not declare anything
 
 // NOWARNINGS-NOT: warning: