[llvm] Avoid out-of-order evaluation in DebugInfo #125116
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@llvm/pr-subscribers-llvm-transforms @llvm/pr-subscribers-debuginfo Author: Elvin Wang (elvinw-intel) ChangesThis is an upstream proposal from intel/intel-graphics-compiler@e60884c Full diff: https://github.com/llvm/llvm-project/pull/125116.diff 1 Files Affected:
diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index 4ce518009bd3ea..ea1d79d436041f 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -798,7 +798,11 @@ class DebugTypeInfoRemoval {
return getReplacementMDNode(N);
};
- Replacements[N] = doRemap(N);
+ // Seperate recursive doRemap and operator [] into 2 lines to avoid
+ // out-of-order evaluations since both of them can access the same memory
+ // location in map Replacements.
+ auto Value = doRemap(N);
+ Replacements[N] = Value;
}
/// Do the remapping traversal.
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We also added the culprit IR that can reproduce the issue on godbolt llvm 's opt14 and opt15, with arg invalid output: correct output: |
Can you include this in the PR as a regression test? |
Sure, where shall I add this lit test? under llvm/test/Transforms/StripNonLineTableDebugInfo or somewhere else? |
seems the existing functionality is tested in llvm/test/Transforms/strip-nonlinetable-debuginfo-* so, another file with that naming pattern, probably? |
This is an upstream proposal from intel/intel-graphics-compiler@e60884c We experienced malfunctioning StripNonLineTableDebugInfo during debugging and it's caused by out-of-order evaluation, this is a C++ level semantic ambiguity issue, refer https://en.cppreference.com/w/cpp/language/eval_order Solution is simply separating one line into two.
added to llvm/test/Transforms/StripNonLineTableDebugInfo/ to follow the name pattern, file named pr125116.ll |
It looks like there isn't already an |
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Hi @dwblaikie test was moved to Transform/Util last week, can u help with the process to move fwd.? |
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This is an upstream proposal from intel/intel-graphics-compiler@e60884c We observed malfunctioning StripNonLineTableDebugInfo during debugging and it's caused by out-of-order evaluation, this is a C++ level semantic ambiguity issue, refer https://en.cppreference.com/w/cpp/language/eval_order Solution is simply separating one line into two.
This is an upstream proposal from intel/intel-graphics-compiler@e60884c We observed malfunctioning StripNonLineTableDebugInfo during debugging and it's caused by out-of-order evaluation, this is a C++ level semantic ambiguity issue, refer https://en.cppreference.com/w/cpp/language/eval_order Solution is simply separating one line into two.
This is an upstream proposal from intel/intel-graphics-compiler@e60884c We observed malfunctioning StripNonLineTableDebugInfo during debugging and it's caused by out-of-order evaluation, this is a C++ level semantic ambiguity issue, refer https://en.cppreference.com/w/cpp/language/eval_order Solution is simply separating one line into two.
This is an upstream proposal from intel/intel-graphics-compiler@e60884c We observed malfunctioning StripNonLineTableDebugInfo during debugging and it's caused by out-of-order evaluation, this is a C++ level semantic ambiguity issue, refer https://en.cppreference.com/w/cpp/language/eval_order Solution is simply separating one line into two.
This is an upstream proposal from intel/intel-graphics-compiler@e60884c
We observed malfunctioning StripNonLineTableDebugInfo during debugging and it's caused by out-of-order evaluation, this is a C++ level semantic ambiguity issue, refer https://en.cppreference.com/w/cpp/language/eval_order
Solution is simply separating one line into two.