Build Target Task 1: Basic Target Parameter Support for llgo build/run/test commands

[cpunion]

Overview

This issue tracks the implementation of Task 1 from the overall cross-platform compilation design (#1176): Adding -target parameter support for llgo build, llgo run, and llgo test commands.

Scope

Build and link parameter configuration support including:

• llvm-target
• goos/goarch
• cflags/ldflags
• linker
• cpu
• features
• build-tags

Implementation Details

Target Configuration System

• Introduce @/targets directory containing JSON configuration files
• Support multi-level inheritance via inherits field
• Automatic parameter merging and overriding

Supported Configuration Fields

• inherits: Array for multi-level inheritance
• llvm-target: LLVM backend target triple
• goos/goarch: Go OS and architecture identifiers
• build-tags: Go build tags for conditional compilation
• cflags/ldflags: C compiler and linker parameters
• features/cpu: CPU features, model
• linker: Specifies the linker to use

Command Integration

Add -target flag support to:

• llgo build -target <target_name>
• llgo run -target <target_name>
• llgo test -target <target_name>

Migration Strategy

• Retain logic for native builds
• Retain wasm/wasip1 logic (SDK download, sysroot/resource-dir automation)
• Use JSON target configs for all other platforms

Related Issues

• Parent issue: Proposal: Build Target Design #1176 (Overall cross-platform compilation design)

Implementation Status

• Status: In Progress
• PR: Build targets task 1: Basic Target Parameter Support for llgo build/run/test commands #1193

Acceptance Criteria

• -target parameter works for build/run/test commands
• Target configuration inheritance system functional
• JSON target configuration parsing implemented
• Existing native and wasm builds unaffected
• Documentation updated