Even though 0 is not a boolean constant, allow this common idiom, to
help in those cases where the C preprocessor used by lint does not mark
tokens as coming from system headers (Clang).
The tests in C11 and C23 mode look the same right now but will change
soon.
The warnings in the C11 test disappeared because after the first error,
warnings about unused variables are suppressed by check_variable_usage,
as they are often wrong.
All changes to the global variable 'dcs' are tracked now, to help
identify the cause of the failing tests in expr_sizeof and
gcc_attribute_aligned.
While here, test more invalid type combinations in typedefs.
Even though the test only uses fixed-size types, lint's computed size of
the resulting struct differs between i386 (80) and x86_64 (112). Both
are wrong, probably due to the unrelated struct declaration above, as
already mentioned in the comments.
The macro 'offsetof(t, m)' already expanded to a constant expression for
scalar members but not for arrays. This was because the macro expanded
to '(size_t)(((t *)0)->m)', which lint internally represents as
'addr(indir(ptr(0) + offset(m)))', and build_address simplifies
'addr(indir(x))' to 'x' if the types match. The types only match for
scalar types though, but not for arrays.
When build_address happens, the type information is incomplete,
therefore 'offsetof(t, array)' has to be simplified at a later point.
The C standards do not specify a fixed type for an array subscript, it
just has to be an integer type. Previously, query 4 fired for the
ubiquitous expression 'ptr[sz]' when sz had type 'size_t'.
The test platform_ilp32_long is unaffected by this change, as the
integer constant 0x80000000 has type 'unsigned int', while size_t is
'unsigned long' on those platforms, and even though the types 'unsigned
int' and 'unsigned long' have the same value space, there's still a
conversion, at least for now.
Previously, an unsigned operation that had a negative result went
undetected in a few cases. Now, all results that are not representable
by their type are considered overflows.
The implementation of signed shift-right had been wrong for a few
commits.
rillig