[SR-4716] Better diagnostics for multifile executable without a main.swift file · swiftlang/swift#47293

(5 留言) (0 反應) (0 負責人)Swift (69,989 star) (10,719 fork)batch import

compilerdiagnostics qualitygood first issueimprovementlegacy driver

描述


Previous ID	SR-4716
Radar	None
Original Reporter	@huonw
Type	Improvement
Status	In Progress
Resolution


Votes	0
Component/s	Compiler
Labels	Improvement, DiagnosticsQoI, Driver, StarterBug
Assignee	None
Priority	Medium

md5: 107a386ff1ef4614f95e66bc776c43f4

Issue Description:

$ touch file1.swift file2.swift
$ swiftc file1.swift file2.swift
Undefined symbols for architecture x86_64:
  "_main", referenced from:
     implicit entry/start for main executable
ld: symbol(s) not found for architecture x86_64
<unknown>:0: error: link command failed with exit code 1 (use -v to see invocation)

The problem here is neither file is called main.swift, so the top-level-code `main` function doesn't get emitted. The compiler should check the file names and emit an error rather than going all the way through compilation to hit the link error.

貢獻者指南

技術棧: swift
領域: developer experiencetooling
議題類型: feature
難度: 3
預計時間: half day
活動狀態: stale
清晰度: clear
前置要求: Swift compiler driver knowledgeFamiliarity with file name detection in compilation pipeline
新手友善度: 50
研究方向: Investigate the Swift compiler driver code, specifically where it determines whether to emit the top level code entry point. The issue suggests adding a check for file names (e.g., main.swift) before the linking step to emit a clear diagnostic. Look for the driver's handling of multiple source files and the condition that checks for a main.swift file. The fix likely involves modifying the driver to produce an error when no main.swift is present among the input files.