microsoft / microsoft/DirectXShaderCompiler

depfile generation isn't supported in the same invocation as compilation

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bug high-impact
Dominant language
C++
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Merged PRs (30d)
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Description

Description
Clang and other compilers with a similar CLI like glslc support -MD -MF in the same invocation of the compiler that does the compilation, which e.g. enables this common pattern in CMake: https://stackoverflow.com/questions/71003674/using-glslcs-depfile-to-make-included-files-automatically-trigger-recompile-of

Steps to Reproduce

dxc -T lib_6_7 -O3 -MD -MF source.d -Fo source.cso source.hlsl

Actual Behavior
The above command line produces source.d but doesn't produce source.cso and doesn't print any errors or warnings either, which is confusing.

Definitely related to #4723

As a workaround for CMake, the add_custom_command can have two COMMAND options for two DXC invocations.

Environment

  • DXC version: 1.7.2207
  • Host Operating System: Win 10

Contributor guide

Open the contributing guide

First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the reported command with DXC and trace the command-line handling for -MD and -MF when compilation is requested in the same invocation. Done means the command produces both source.d and source.cso, reports appropriate diagnostics, and has regression coverage for this invocation.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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