forked from OSchip/llvm-project
facb3ac385
Salvage debug info of instruction that is about to be deleted as dead in Combiner pass. Currently supported instructions are COPY and G_TRUNC. It allows to salvage debug info of some dead arguments of functions, by putting DWARF expression corresponding to the instruction being deleted into related DBG_VALUE instruction. Here is an example of missing variables location https://godbolt.org/z/K48osb9dK. We see that arguments x, y of function foo are not available in debugger, and corresponding DBG_VALUE instructions have undefined register operand instead of variables locaton after Aarch64PreLegalizerCombiner pass. The reason is that registers where variables are located are removed as dead (with instruction G_TRUNC). We can use salvageDebugInfo analogue for gMIR to preserve debug locations of dead variables. Statistics of llvm object files built with vs without this commit on -O2 optimization level (CMAKE_BUILD_TYPE=RelWithDebInfo, -fglobal-isel) on Aarch64 (macOS): Number of variables with 100% of parent scope covered by DW_AT_location has been increased by 7,9%. Number of variables with 0% coverage of parent scope has been decreased by 1,2%. Number of variables processed by location statistics has been increased by 2,9%. Average PC ranges coverage has been increased by 1,8 percentage points. Coverage can be improved by supporting more instructions, or by calling salvageDebugInfo for instructions that are deleted during Combiner rules exection. Reviewed By: aprantl Differential Revision: https://reviews.llvm.org/D129909 |
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| .. | ||
| Analysis | ||
| Assembler | ||
| Bindings | ||
| Bitcode | ||
| BugPoint | ||
| CodeGen | ||
| DebugInfo | ||
| Demangle | ||
| Examples | ||
| ExecutionEngine | ||
| Feature | ||
| FileCheck | ||
| Instrumentation | ||
| Integer | ||
| JitListener | ||
| LTO | ||
| Linker | ||
| MC | ||
| MachineVerifier | ||
| Object | ||
| ObjectYAML | ||
| Other | ||
| SafepointIRVerifier | ||
| Support | ||
| SymbolRewriter | ||
| TableGen | ||
| ThinLTO/X86 | ||
| Transforms | ||
| Unit | ||
| Verifier | ||
| YAMLParser | ||
| tools | ||
| .clang-format | ||
| CMakeLists.txt | ||
| TestRunner.sh | ||
| lit.cfg.py | ||
| lit.site.cfg.py.in | ||