swiftlang/swift

[SR-6082] Produce a better error message if Swift is run on a system without clang++

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#48,637 opened on Oct 6, 2017

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Linuxcompilergood first issueimprovementlegacy driver

Description
Previous ID SR-6082
Radar rdar://problem/23197056
Original Reporter @belkadan
Type Improvement
Votes 0
Component/s Compiler
Labels Improvement, Driver, Linux, StarterBug
Assignee None
Priority Medium

md5: 0ed0a272c70aa068a13e89f859372a45

relates to:

  • SR-834 Very unhelpful error message when clang++ cannot be invoked

Issue Description:

Swift on Linux (and other non-Apple platforms) calls clang++ to perform linking; if it's not found, we used to get this lousy error message:

<unknown>:0: error: link command failed with exit code 127 (use -v to see invocation)

We should do better. (It's possible we already do do better; I just don't have access to a Linux system without clang++ installed at the moment. If you have such a system, you can help out with this bug by downloading Swift from https://swift.org/download/ and seeing what echo 'print("hello")' | swiftc - produces.)

Contributor guide

Tech stack
swift
Domain
developer experiencetooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Swift compiler basicsLinux system without clang++
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
First, verify the current error message on a Linux system without clang++ by running `echo 'print("hello")' | swiftc `. Then, locate the Swift driver code that invokes clang++ for linking (likely in the driver or BuildExecution module). Improve the error message to clearly indicate that clang++ is missing and suggest installation. Refer to the linked issue SR 834 for previous context.