Many of the Managed methods accepted by-val parameters which could
reference Limb slices that became invalid memory after any
ensureCapacity calls. Now, Managed methods accept `*const Managed`
parameters so that if the function allows aliasing and the
ensure-capacity call resizes the Limb slice, it also affects the
aliased parameters, avoiding use-after-free bugs.
This is a breaking change that reduces the requirement for callsites to
manually make the ensure-capacity changes prior to calling many of the
Managed methods.
Closes#11897
This reverts commit 8bf3e1f8d0902abd4133e2729b3625c25011c3ff, which
introduced miscompilations for peer expressions any time they needed
coercions to runtime types.
I opened #11957 as a proposal to accomplish the goal of the reverted
commit.
Closes#11898
This comment is now deleted because the task is completed in this
commit:
```
// TODO: Update this to behave like `beginComptimePtrLoad` and properly check/use
// `container_ty` and `array_ty`, instead of trusting that the parent decl type
// matches the type used to derive the elem_ptr/field_ptr/etc.
//
// This is needed because the types will not match if the pointer we're mutating
// through is reinterpreting comptime memory.
```
The main strategy is to change the ComptimePtrMutationKit struct so that
instead of `val: *Value` it now returns a tagged union which can be one
of three possibilities:
* The pointer type matches the actual comptime Value so a direct
modification is possible. Before this commit, the implementation
incorrectly assumed this was always the case.
* In the case of needing to write through a reinterpreted pointer, a
mutable base Value pointer is provided along with a byte offset
pointing to the element value in virtual memory.
* Otherwise, it means a compile error must be emitted because one or
both of the types (the owner of the value, or the pointer type being
used to write through) do not have a well-defined memory layout.
After calling beginComptimePtrMutation, the one callsite now switches on
this tagged union and does the appropriate thing. The main new logic is
for the second case, which involves pointer reinterpretation, which now
takes this strategy:
1. write the base value to a memory buffer.
2. perform the pointer store at the proper byte offset, thereby
modifying a subset of the buffer.
3. read the base value from the memory buffer, overwriting the old base
value.
This commit does not change any behavior, but changes the type of
the runtime_index field from u32 to a non-exhaustive enum. This allows
us to put `std.math.maxInt(u32)` only in the enum type definition and
give it an official meaning.
And use it to debug a LazySrcLoc in stage2 that is set to a bogus value.
The actual fix in this commit is:
```diff
- try sema.emitBackwardBranch(&child_block, call_src);
+ try sema.emitBackwardBranch(block, call_src);
```
This function took is_ptr: bool and then branched on it three times.
Now, instead, each implementation does no branching and the logic is
easier to follow, both for maintainers and compilers.
I also fixed a bug with TryPtr not ensuring enough capacity in the extra
array.
* Introduce "_ptr" variants of ZIR try instruction to disallow constructs
such as `try` on a pointer value instead of an error union value.
* Disable the "_inline" variants of the ZIR try instruction for now because
we are out of ZIR tags. I will free up some space in an independent commit.
* AstGen: fix tryExpr calling rvalue() on ResultLoc.ref
Implements semantic analysis for the new try/try_inline ZIR
instruction. Adds the new try/try_ptr AIR instructions and implements
them for the LLVM backend.
Fixes not calling rvalue() for tryExpr in AstGen.
This is part of an effort to implement #11772.
