Add support for OffsetOfExpr that contain exactly 1 component, when that component
is a field.
For example, given:
```c
struct S {
float f;
double d;
};
struct T {
long l;
int i;
struct S s[10];
};
```
Then:
```c
offsetof(struct T, i) // supported
offsetof(struct T, s[2].d) // not supported currently
```
Add a new allocated_registers bitmap to keep track of all callee-saved
registers allocated during generation of this function.
Function(.arm).gen uses this data to generate instructions in the
function prologue and epilogue to push and pop these registers
respectively.
When two pointers are subtracted, both shall point to elements of the
same array object, or one past the last element of the array object;
the result is the difference of the subscripts of the two array elements.
The size of the result is implementation-defined, and its type
(a signed integer type) is ptrdiff_t defined in the <stddef.h> header.
If the result is not representable in an object of that type,
the behavior is undefined.
See C Standard, §6.5.6 [ISO/IEC 9899:2011]
Fixes#7216
If the type is a reference to a global declaration that has not yet
been translated we need to use the global scope for translation
so that other functions can also reference it.
All stage2 tests are passing again in this branch.
Remaining checklist for this branch:
* get the rest of the zig fmt test cases passing
- re-enable the translate-c test case that is blocking on this
* implement the 2 `@panic(TODO)`'s in parse.zig
* use fn_proto not fn_decl for extern function declarations
Now it builds and what remains in this branch is:
* fix the stage2 compiler regressions from this branch
* finish the rest of zig fmt test cases, get them passing
* Merge in Vexu's translate-c AST branch & fix translate-c regressions
This type is not widely applicable enough to be a public part of the
public interface of the std.
The current implementation in only fully utilized by the zig fmt
implementation, which could benefit by even tighter integration as
will be demonstrated in the next commit. Therefore, move the current
io.AutoIndentingStream to lib/std/zig/render.zig.
The C backend of the self hosted compiler also use this type currently,
but it does not require anywhere near its full complexity. Therefore,
implement a greatly simplified version of this interface in
src/codegen/c.zig.
jacob gw