debuginfo: Line-tables-only mode emits much more debuginfo than Clang #64405
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A-debuginfo
Area: Debugging information in compiled programs (DWARF, PDB, etc.)
A-LLVM
Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues.
C-cleanup
Category: PRs that clean code up or issues documenting cleanup.
C-feature-request
Category: A feature request, i.e: not implemented / a PR.
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
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michaelwoerister
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C-cleanup
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How can we possibly reduce the amount of debug info in |
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The only route I see is adding more flags ( |
Changing the exact behavior of a codegen flag seems like a very liberal definition of "breaking" ... what if we added a new |
This was referenced Mar 18, 2023
saethlin
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to saethlin/miri
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this issue
Apr 10, 2023
Extend -Cdebuginfo with new options and named aliases This is a rebase of rust-lang/rust#83947, along with my best guess at what the new options mean. I tried to follow the LLVM source code to get a better idea but ran into quite a lot of trouble (https://rust-lang.zulipchat.com/#narrow/stream/187780-t-compiler.2Fwg-llvm/topic/go-to-definition.20in.20src.2Fllvm-project.3F). The description for the original PR follows below. Note that the changes in this PR have already been through FCP: rust-lang/rust#83947 (comment) Closes rust-lang/rust#109311. Helps with rust-lang/rust#104968. r? `@michaelwoerister` cc `@cuviper` --- The -Cdebuginfo=1 option was never line tables only and can't be due to backwards compatibility issues. This was clarified and an option for emitting line tables only was added. Additionally an option for emitting line info directives only was added, which is needed for some targets, i.e. nvptx. The debug info options should now behave similarly to clang's debug info options. Fix rust-lang/rust#60020 Fix rust-lang/rust#64405
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We probably could emit less debuginfo when compiling with
-Cdebuginfo=1than we do at the moment. Clang 8.0 emits a lot less debuginfo when compiling with-gline-tables-only, with debuginfo not containing anyDW_TAG_subprogramentries; while stepping through the code with gdb still works.However, reducing the amount of debuginfo emitted should be done with care since external tools rely on the current behavior (see e.g. #60020).
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