Added Aarch64 extern function support

[RealA10N]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 39 lines in your changes missing coverage. Please review.

Project coverage is 42.32%. Comparing base (6cbf2ca) to head (dd8855f).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
aarch64/isa/bl.go	0.00%	19 Missing ⚠️
aarch64/codegen/file.go	0.00%	12 Missing ⚠️
aarch64/translation/file.go	0.00%	6 Missing ⚠️
aarch64/codegen/instruction.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #46      +/-   ##
==========================================
- Coverage   42.60%   42.32%   -0.28%     
==========================================
  Files         114      114              
  Lines        4253     4281      +28     
==========================================
  Hits         1812     1812              
- Misses       2355     2383      +28     
  Partials       86       86              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Copilot]

Pull Request Overview

This pull request introduces support for Aarch64 extern functions by updating symbol handling, branch relocation registration, and file code generation context.

• Conditionally set symbol properties for defined functions in the translation phase.
• Register relocations for branch instructions when target offsets are unavailable.
• Add helper methods for computing instruction offsets and manage function indices and relocations in file codegen.

Reviewed Changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated no comments.

File	Description
aarch64/translation/file.go	Updates symbol creation to conditionally set section and offset for defined functions.
aarch64/isa/bl.go	Adds relocation registration and updates branch instruction generation.
aarch64/codegen/instruction.go	Introduces a helper to compute instruction offset in file.
aarch64/codegen/file.go	Enhances file codegen context with function indices and relocations management.

Files not reviewed (2)

• examples/aarch64/bl-extern.usm: Language not supported
• go.mod: Language not supported

Comments suppressed due to low confidence (2)

aarch64/translation/file.go:37

• The conditional update of symbol properties for defined functions may leave undefined symbols with zero or uninitialized section and offset values; please confirm that this behavior is intentional and that it will not adversely affect symbol resolution.

if function.IsDefined() {

aarch64/isa/bl.go:43

• Returning a BL(0) placeholder when the target offset lookup fails could inadvertently introduce an incorrect branch target; consider defining a clear fallback strategy or documenting why BL(0) is safe in this context.

targetOffset, ok := ctx.FunctionOffsets[b.Target]