Given a pointer operand `ptr` and a signed integer operand `idx`
`ptr + idx` and `idx + ptr` -> ptr + @bitCast(usize, @intCast(isize, idx))
`ptr - idx` -> ptr - @bitCast(usize, @intCast(isize, idx))
Thanks @LemonBoy for pointing out that we can take advantage of wraparound
to dramatically simplify the code.
* Now it supports being an lvalue (see additional lines in the test
case).
* Properly handles a pointer result location (see additional lines in
the test case that assign the result of the orelse to a variable
rather than a const).
* Properly sets the result location type when possible, so that type
inference of an `orelse` operand expression knows its result type.
We can now codegen optionals! This includes the following instructions:
- is_null
- is_null_ptr
- is_non_null
- is_non_null_ptr
- optional_payload
- optional_payload_ptr
- br_void
Also includes a test for optionals.
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
```
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
The previous iteration of translate-c used an incorrect block label
in the break statement for a translated C statement expression. This adds
a test to ensure the correct label is used in the new intermediate AST
version of translate-c.
In C, if a function has return type `int` and the return expression
is a boolean expression, there is no implicit cast. Therefore the
translated Zig code needs to call @boolToInt() on the result.
Written with feedback from @Vexu
Fixes#6215
The astgen for switch expressions did not respect the ZIR rules of only
referencing instructions that are in scope:
%14 = block_comptime_flat({
%15 = block_comptime_flat({
%16 = const(TypedValue{ .ty = comptime_int, .val = 1})
})
%17 = block_comptime_flat({
%18 = const(TypedValue{ .ty = comptime_int, .val = 2})
})
})
%19 = block({
%20 = ref(%5)
%21 = deref(%20)
%22 = switchbr(%20, [%15, %17], {
%15 => {
%23 = const(TypedValue{ .ty = comptime_int, .val = 1})
%24 = store(%10, %23)
%25 = const(TypedValue{ .ty = void, .val = {}})
%26 = break("label_19", %25)
},
%17 => {
%27 = const(TypedValue{ .ty = comptime_int, .val = 2})
%28 = store(%10, %27)
%29 = const(TypedValue{ .ty = void, .val = {}})
%30 = break("label_19", %29)
}
}, {
%31 = unreachable_safe()
}, special_prong=else)
})
In this snippet you can see that the comptime expr referenced %15 and
%17 which are not in scope. There also was no test coverage for runtime
switch expressions.
Switch expressions will have to be re-introduced to follow these rules
and with some test coverage. There is some usable code being deleted in
this commit; it will be useful to reference when re-implementing switch
later.
A few more improvements to do while we're at it:
* only use .ref result loc on switch target if any prongs obtain the
payload with |*syntax|
- this improvement should be done to if, while, and for as well.
- this will remove the needless ref/deref instructions above
* remove switchbr and add switch_block, which is both a block and a
switch branch.
- similarly we should remove loop and add loop_block.
This commit introduces a "force_comptime" flag into the GenZIR
scope. The main purpose of this will be to choose the "comptime"
variants of certain key zir instructions, such as function calls and
branches. We will be moving away from using the block_comptime_flat
ZIR instruction, and eventually deleting it.
This commit also contains miscellaneous fixes to this branch that bring
it to the state of passing all the tests.
