Issue #100 demonstrated that register allocation for aliased registers is
fundamentally broken. The root of the issue is that currently accesses to the
same virtual register with different masks are treated as different registers.
This PR takes a different approach:
* Liveness analysis is masked: we now properly consider which parts of a register are live
* Register allocation produces a mapping from virtual to physical ID, and aliasing is applied later
In addition, a new pass ZeroExtend32BitOutputs accounts for the fact that 32-bit writes in 64-bit mode should actually be treated as 64-bit writes (the result is zero-extended).
Closes#100
Go added the TOPFRAME attribute in https://golang.org/cl/169726/. This diff adds the new attribute to avo, and also updates handling of the REFLECTMETHOD attribute.
Adds support for a `CancellingInputs` instruction flag, to indicate cases like `XORQ R10, R10` where the instruction actually does not depend on the value of `R10` at all.
Closes#89
In jump-table-like constructs, the natural way of writing the code can sometimes produce redundant jumps or labels. Therefore some basic cleanup steps have been proposed. This diff adds two transforms:
1. Remove unconditional jumps to a label immediately following.
2. Remove labels with no references at all.
Fixes#75
In some cases natural use of abstraction in avo programs can lead to redundant move instructions, specifically self-moves such as MOVQ AX, AX. This does not produce incorrect code but it is incorrect and inelegant.
This diff introduces a PruneSelfMoves pass that removes such unnecessary instructions.
Closes#76
The Go assembler merges MOVD/MOVQ instruction forms. The logic in the
avo instruction loader was discarding the MOVD forms. This diff should
merge them correctly.
Updates #50
Run asmfmt suring linting and confirm git repository isn't dirty.
This introduces a developer tools dependency on asmfmt, but not a
runtime dependency.
Updates #8
The Context.Label method and LABEL global function did not agree. Also
breaks the convention I'd like to set that capitalized functions must
agree with existing Go assembly syntax.
To help avoid a conflict with `avo.Label`, attributes were moved to
their own package.
Fixes#35
Adds methods for referencing sub- or super-registers. For example, for
general purpose registers you can now reference As8(), As16(), ... and
for vector AsX(), AsY(), AsZ().
Closes#1
