Addr2line enhance 5#4977
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…able overlay
Refactor the wasm symbolicator to make its DWARF workaround explicit
and unconditional. addr2line.py runs one llvm-symbolizer -f -i call
per address, then overlays the outermost frame's function name from a
startup-built DWARF interval table.
The overlay exists because llvm-symbolizer returns the wrong outermost
function name on wasm targets for two independent, source-verified
reasons:
- Symbol-table override on the outermost frame (LLVM design, not a
bug). symbolizeInlinedCode in llvm/lib/DebugInfo/Symbolize/
SymbolizableObjectFile.cpp unconditionally rewrites the outermost
frame's FunctionName from getNameFromSymbolTable when
FunctionNameKind::LinkageName and UseSymbolTable are both set, which
is the default. Inline frames come from getInliningInfoForAddress
(a different code path) and are provably immune.
- AddrDieMap invariant violation from wasm-opt -Oz -g DCE ghosts.
LocationUpdater::getNewFuncStart in binaryen's src/wasm/wasm-debug.cpp
returns 0 as a tombstone when an old address doesn't map to a
surviving IR node, and updateDIE writes it into DW_AT_low_pc without
removing the DW_TAG_subprogram. LLVM's updateAddressDieMap in
DWARFUnit.cpp requires child ranges ⊆ parent ranges; these ghosts
break that invariant so the map's upper_bound − 1 lookup returns
an insertion-order-dependent DIE.
Both mechanisms produce the same "wrong outermost frame name" symptom
and both apply on any supported wasi-sdk, so the overlay runs on every
resolution. build_subprogram_intervals filters three DIE classes at
parse time: DW_AT_declaration=true (forward decls), low_pc == 0
(DWARF Code-section-relative zero is the function-count LEB, not a
real body — this is the DCE-ghost pattern), and high_pc <= low_pc
(degenerate ranges). The innermost covering DW_TAG_subprogram wins.
Also includes accumulated tool improvements:
- --mode flag {interp,aot,fast-interp} for different runtime offset
conventions (interp post-advance, aot at-instruction-start,
fast-interp's transformed in-memory bytecode)
- Inline frame annotation "(inlined into <next>)" for clarity
- llvm-symbolizer preferred over llvm-addr2line for column info
- Fallback for offset=0 (trap at function entry; frame_ip not captured)
- Last-resort function-index name fallback when DWARF lacks PC ranges
Full design rationale, source citations, and empirical truth table in
test-tools/addr2line/README.md.
- README: document the --mode flag and inline expansion behavior, and point to the tool README for the interval-table overlay rationale. - symbolicate.sh: pass --mode aot for the AOT call-stack invocation. - verify.sh (new): assertion-based smoke test that runs the existing symbolicate.sh and grep-checks for inline expansion (trap_helper) in both the wasm and AOT outputs. Replaces the inline assertions the CI step previously carried. - wasm-apps/trap.c: add a trap_helper marked __attribute__((always_inline)) that the trap site falls inside, so addr2line.py can demonstrate inline-frame annotation against this sample. Depends on the addr2line.py refactor (--mode flag).
New self-contained sample demonstrating the full production-debug workflow for optimized WASM: - 4-step build pipeline (clang -Oz -g -flto, wasm-opt -Oz -g, llvm-strip --strip-all, wamrc) producing prod.wasm + prod.aot + debug.wasm companion artifacts. - Two test apps (oob, stackoverflow) split into multi-file C sources to exercise cross-TU LTO inlining. - USE_FAST_INTERP CMake option to build iwasm in classic or fast-interp mode for testing. - symbolicate.sh: end-to-end driver that runs iwasm on the prod binary, captures the call stack, and resolves it via addr2line.py + the debug companion. Auto-detects classic vs fast-interp from the iwasm binary. - verify.sh: per-(app, mode) assertion that the symbolicated output contains the expected source files. Used by CI. Depends on the addr2line.py refactor (--mode flag is invoked from symbolicate.sh).
New test suite at test-tools/addr2line/tests/ exercising addr2line.py against purpose-built C/C++ sources covering the interval-table overlay contract and the tool's other behaviors: - Baseline single-function resolution - Inline expansion (always_inline, 4-level deep chain) - Cross-TU LTO inlining (multi-file recursion + wasm-opt -Oz -g, which exercises both LLVM outermost-name failure modes) - Trap inside loop body (DWARF line-table edge case) - Multi-frame call stack - C++ symbol demangling - AOT mode offset math - fast-interp / --no-addr fallbacks - offset=0 fallback (trap at function entry) - Empty input - Skip-guard invariant on build_subprogram_intervals (test_build_subprogram_intervals_filters_invalid_dies): rejects DW_AT_declaration=true DIEs, low_pc == 0 (wasm-opt DCE ghosts), and high_pc <= low_pc entries at parse time. Layout: test-tools/addr2line/tests/ ├── README.md -- documentation ├── conftest.py -- pytest fixtures (sdk discovery, build, │ run_addr2line invocation, multi-sdk │ parametrization) ├── test_addr2line.py -- 12 test cases ├── pytest.ini -- marker definitions (slow, multi_sdk) ├── run_tests.sh -- thin pytest wrapper ├── apps/ -- 8 purpose-built C/C++ sources └── fixtures/ -- 3 plaintext call-stack inputs Sources under apps/ are NOT copied from samples/; they target specific edge cases independent of sample evolution. Multi-SDK mode (--multi-sdk) parametrizes build-based tests over every detected wasi-sdk under /opt to catch DWARF-encoding differences between clang versions. Depends on the addr2line.py refactor.
compilation_on_android_ubuntu.yml: - Existing build_samples_others step (debug-tools) now calls verify.sh instead of inline grep assertions. - New build_samples_debug_tools_optimized job: builds the new sample twice (classic-interp and fast-interp via -DUSE_FAST_INTERP=ON) and runs verify.sh oob/stackoverflow x wasm/aot for each build. - New addr2line_tests job: runs the pytest suite at test-tools/addr2line/tests/ against the default wasi-sdk on every PR. nightly_run.yml: - New addr2line_tests_multi_sdk job: installs wasi-sdk 29.0 (clang 21) and 33.0 (clang 22) side by side and runs the test suite with --multi-sdk so build-based tests are re-run once per SDK, catching DWARF-encoding differences between clang versions. Depends on: - the addr2line.py refactor (per-PR job runs the test suite) - samples/debug-tools refresh (existing sample CI step now calls verify.sh) - samples/debug-tools-optimized (new job builds and tests it) - the pytest suite (new jobs invoke pytest)
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