The idea here is that there are two ways we can reference a function at runtime:
* Through a direct call, i.e. where the function is comptime-known
* Through a function pointer
This means we can easily perform a form of rudimentary escape analysis
on functions. If we ever see a `decl_ref` or `ref` of a function, we
have a function pointer, which could "leak" into runtime code, so we
emit the function; but for a plain `decl_val`, there's no need to.
This change means that `comptime { _ = f; }` no longer forces a function
to be emitted, which was used for some things (mainly tests). These use
sites have been replaced with `_ = &f;`, which still triggers analysis
of the function body, since you're taking a pointer to the function.
Resolves: #6256Resolves: #15353
Instead of using `zig test` to build a special version of the compiler
that runs all the test-cases, the zig build system is now used as much
as possible - all with the basic steps found in the standard library.
For incremental compilation tests (the ones that look like foo.0.zig,
foo.1.zig, foo.2.zig, etc.), a special version of the compiler is
compiled into a utility executable called "check-case" which checks
exactly one sequence of incremental updates in an independent
subprocess. Previously, all incremental and non-incremental test cases
were done in the same test runner process.
The compile error checking code is now simpler, but also a bit
rudimentary, and so it additionally makes sure that the actual compile
errors do not include *extra* messages, and it makes sure that the
actual compile errors output in the same order as expected. It is also
based on the "ends-with" property of each line rather than the previous
logic, which frankly I didn't want to touch with a ten-meter pole. The
compile error test cases have been updated to pass in light of these
differences.
Previously, 'error' mode with 0 compile errors was used to shoehorn in a
different kind of test-case - one that only checks if a piece of code
compiles without errors. Now there is a 'compile' mode of test-cases,
and 'error' must be only used when there are greater than 0 errors.
link test cases are updated to omit the target object format argument
when calling checkObject since that is no longer needed.
The test/stage2 directory is removed; the 2 files within are moved to be
directly in the test/ directory.
