[SR-6055] When given the -output-file-map= option, the driver should check the map file exists (and other improvements) · swiftlang/swift#48612

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

compilergood first issueimprovementlegacy driver

描述


Previous ID	SR-6055
Radar	None
Original Reporter	@modocache
Type	Improvement


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

md5: f1f04b7b7601fefc78802b4bc77a7cb3

Issue Description:

This task tracks two TODOs left in swift/lib/Driver/Driver.cpp three years ago: "perform some preflight checks to ensure the [output map] file exists", and "emit [a] diagnostic with error string [explaining why the file could not be opened]".

Other parts of this Driver.cpp file use the llvm::sys::fs::exists() function in order to check a file exists before the driver proceeds with execution. The same should be done here, so that the user can be notified of a missing file before the driver attempts to open and read on the next line.

Further, assuming the file exists, but the driver is unable to open it on the next line for some reason, an error diagnostic with the reason why should be surfaced. swift/lib/Driver/OutputFileMap.cpp appears to use LLVM functions to open and read the file, and these functions return error objects/codes. Those errors should have a message associated with them, although I don't know the API to read that message off the top of my head.

貢獻者指南

技術棧: swiftcpp
領域: backendtooling
議題類型: feature
難度: 3
預計時間: 1-3 hours
活動狀態: stale
清晰度: mostly clear
前置要求: C++LLVM error handlingSwift compiler driver
新手友善度: 40
研究方向: The issue points to two TODOs in `swift/lib/Driver/Driver.cpp` at lines 1667-1671. The goal is to add a preflight check using `llvm::sys::fs::exists()` to verify the output file map exists before attempting to open it, and to surface an error diagnostic if opening fails. Look at how `Driver.cpp` uses `llvm::sys::fs::exists()` elsewhere for similar checks, and examine `swift/lib/Driver/OutputFileMap.cpp` to understand how LLVM error objects can be queried for error messages. The remaining research is to determine the exact API for extracting the error string from the LLVM error return.