This branch adds "builtin" and "std" to the import table when using the
self-hosted backend.
"builtin" gains one additional item:
```
pub const zig_is_stage2 = true; // false when using stage1 backend
```
This allows the std lib to do conditional compilation based on detecting
which backend is being used. This will be removed from builtin as soon
as self-hosted catches up to feature parity with stage1.
Keep a sharp eye out - people are going to be tempted to abuse this.
The general rule of thumb is do not use `builtin.zig_is_stage2`. However
this commit breaks the rule so that we can gain limited start.zig support
as we incrementally improve the self-hosted compiler.
This commit also implements `fullyQualifiedNameHash` and related
functionality, which effectively puts all Decls in their proper
namespaces. `fullyQualifiedName` is not yet implemented.
Stop printing "todo" log messages for test decls unless we are in test
mode.
Add "previous definition here" error notes for Decl name collisions.
This commit does not bring us yet to a newly passing test case.
Here's what I'm working towards:
```zig
const std = @import("std");
export fn main() c_int {
const a = std.fs.base64_alphabet[0];
return a - 'A';
}
```
Current output:
```
$ ./zig-cache/bin/zig build-exe test.zig
test.zig:3:1: error: TODO implement more analyze elemptr
zig-cache/lib/zig/std/start.zig:38:46: error: TODO implement structInitExpr ty
```
So the next steps are clear:
* Sema: improve elemptr
* AstGen: implement structInitExpr
This refactor inserts an offset table into wasm's data section
where each offset points to the actual data region.
This means we can keep offset indexes consistant and do not
have to perform any computer to determine where in the data section
something like a static string exists. Instead during runtime
it will load the data offset onto the stack.
The following code caused an assertion to be hit:
```
pub fn main() void {
var e: anyerror!c_int = error.Foo;
const i = e catch 69;
assert(69 - i == 0);
}
```
There were several problems, all fixed:
* AstGen was storing field names as references to the original
source code bytes. However, that data would be destroyed when the
source file is updated. Now, it correctly stores the field names in
the Decl arena for the enum. The same fix applies to error set field
names.
* Sema was missing a memset inside `analyzeSwitch`, leaving the "seen
enum fields" array with undefined memory. Now that they are all
properly set to null, the validation works.
* Moved the "enum declared here" note to the end. It looked weird
interrupting the notes for which enum values were missing.
Before, incremental compilation would crash when trying to emit compile
errors for the update after introducing a parse error.
Parse errors are handled by not invalidating any existing semantic
analysis. However, only the parse error must be reported, with all the
other errors suppressed. Once the parse error is fixed, the new file can
be treated as an update to the previously-succeeded update.
* `analyzeContainer` now has an `outdated_decls` set as well as
`deleted_decls`. Instead of queuing up outdated Decls for re-analysis
right away, they are added to this new set. When processing the
`deleted_decls` set, we remove deleted Decls from the
`outdated_decls` set, to avoid deleted Decl pointers from being in
the work_queue. Only after processing the deleted decls do we add
analyze_decl work items to the queue.
* Module.deletion_set is now an `AutoArrayHashMap` rather than `ArrayList`.
`declareDeclDependency` will now remove a Decl from it as appropriate.
When processing the `deletion_set` in `Compilation.performAllTheWork`,
it now assumes all Decl in the set are to be deleted.
* Fix crash when handling parse errors. Currently we unload the
`ast.Tree` if any parse errors occur. Previously the code emitted a
LazySrcLoc pointing to a token index, but then when we try to resolve
the token index to a byte offset to create a compile error message,
the ast.Tree` would be unloaded. Now we use
`LazySrcLoc.byte_abs` instead of `token_abs` so the error message can
be created even with the `ast.Tree` unloaded.
Together, these changes solve a crash that happened with incremental
compilation when Decls were added and removed in some combinations.
off by one error in the bits that describe defaults/field alignments
as soon as we have tests for struct field alignment and default values,
there will be coverage for this.
Now that we're close to supporting all the types, get rid of the `else`
prong and explicitly list out those types that are not yet implemented.
Thanks @g-w1
