build: add command tracing and entry module name

[cpunion]

Summary

• Add -x flag to print build commands for tracing, separate from -v.
• Keep entry module name as entry_main to avoid confusing it with a real main package in logs/traces.

Details

• -x prints the exact commands executed during compile/link/run, and can be combined with -v.
• Command tracing also covers relevant Cgo clang invocations.

Testing

• Not run (PR description only)

[gemini-code-assist]

Summary of Changes

Hello @cpunion, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the build system's observability by introducing a dedicated command tracing mechanism via the -x flag. This allows users to see the exact commands being executed at various stages of compilation, linking, and execution. Additionally, it refines the internal naming convention for the main entry module during linking, contributing to overall system consistency and improved debugging capabilities.

Highlights

• Command Tracing Flag: Introduced a new command-line flag, -x, to enable detailed tracing of commands executed during the build, compile, link, and run phases. This provides greater visibility into the build process.
• Refactored Flag Handling: The -x flag was refactored from a combined flag with -n in cmd/internal/base/pass.go to its own explicit definition in cmd/internal/flags/flags.go, improving clarity and control.
• Entry Module Naming: Standardized the name of the main entry module during the linking process to a fixed string "entry_main" instead of using a dynamic package path.
• Integrated Verbosity: The new command tracing functionality is integrated with existing verbose logging, allowing either the -x flag or the verbose flag to trigger command output for various operations.
• Cgo Command Tracing: Extended command tracing to include clang invocations related to Cgo processing, specifically for extracting macro and function names, enhancing debugging for Cgo interactions.

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[xgopilot]

Code Review Summary

This PR successfully adds command tracing (-x flag) separate from verbose mode, improving debugging capabilities. The implementation is largely sound with good separation of concerns.

Key improvements:
✅ Clean separation of -x (print commands) from -v (verbose output)
✅ Consistent command printing across compilation, linking, and runtime phases
✅ Better tracing context with package names in output

Issues identified:
⚠️ Inconsistent verbose parameter handling in buildPkg (see inline comment)
💡 Entry module name change needs documentation
💡 Consider helper method for shouldPrintCommands pattern

Testing recommendation: Add tests verifying -x behavior independently and combined with -v.

Overall, this is a valuable addition that will help users understand build processes. The inline comments highlight areas for refinement.

[gemini-code-assist]

Code Review

This pull request introduces command tracing via a new -x flag and refines the entry module naming for better logging. The changes are well-implemented and consistently applied across the build system. The new flag enhances debuggability by allowing users to see the exact commands being executed. I have a couple of minor suggestions to improve code readability and maintainability.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.01%. Comparing base (298669b) to head (ed21fe3).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1584   +/-   ##
=======================================
  Coverage   91.01%   91.01%           
=======================================
  Files          45       45           
  Lines       11971    11971           
=======================================
  Hits        10896    10896           
  Misses        899      899           
  Partials      176      176           

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