Converting a pointer to an integer whose result cannot represented in the
integer type is undefined behavior is C and prohibited in C++. C++ already
has a diagnostic when casting. This adds a diagnostic for C.
Since this diagnostic uses the range of the conversion it also modifies
int-to-pointer-cast diagnostic to use a range.
Fixes PR8718: No warning on casting between pointer and non-pointer-sized int
Differential Revision: https://reviews.llvm.org/D72231
null comparison when the pointer is known to be non-null.
This catches the array to pointer decay, function to pointer decay and
address of variables. This does not catch address of function since this
has been previously used to silence a warning.
Pointer to bool conversion is under -Wbool-conversion.
Pointer to null comparison is under -Wtautological-pointer-compare, a sub-group
of -Wtautological-compare.
void foo() {
int arr[5];
int x;
// warn on these conditionals
if (foo);
if (arr);
if (&x);
if (foo == null);
if (arr == null);
if (&x == null);
if (&foo); // no warning
}
llvm-svn: 202216
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
llvm-svn: 91446
helper isConstantInitializer) to check whether an initializer is
constant. This passes tests, but it's possible that it'll cause
regressions with real-world code.
Future work:
1. The diagnostics obtained this way are lower quality at the moment;
some work both here and in Evaluate is needed for accurate diagnostics.
2. We probably need some extra code when we're in -pedantic mode so we
can strictly enforce the rules in C99 6.6p7.
3. Dead code cleanup (this should wait until after 2, because we might
want to re-use some of the code).
llvm-svn: 65265
required by the standard (the standard doesn't know anything about
implicit casts).
Disallow pointers cast to non-integral arithmetic types as constant
expressions. This was previously allowed by accident.
llvm-svn: 51779
Mark de Wever