[Based on #139] debug: validate fault boundaries and final Wasm DWARF

.github/workflows/browser-debug.yml

@@ -47,6 +47,29 @@ jobs:
         with:
           version: "4.0.21"
 
+      - name: Build Binaryen with final-DWARF repair
+        shell: bash
+        env:
+          BINARYEN_REVISION: 0c439cce601d5812209df1fc1188afe90100fca6
+        run: |
+          set -euo pipefail
+          source_dir="${GITHUB_WORKSPACE}/.tools/binaryen"
+          build_dir="${GITHUB_WORKSPACE}/.tools/binaryen-build"
+          git init "${source_dir}"
+          git -C "${source_dir}" remote add origin \
+            https://github.com/cpunion/binaryen.git
+          git -C "${source_dir}" fetch --depth=1 origin \
+            "${BINARYEN_REVISION}"
+          git -C "${source_dir}" checkout --detach FETCH_HEAD
+          test "$(git -C "${source_dir}" rev-parse HEAD)" = \
+            "${BINARYEN_REVISION}"
+          cmake -S "${source_dir}" -B "${build_dir}" -G Ninja \
+            -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTS=OFF
+          cmake --build "${build_dir}" \
+            --target wasm-opt wasm-emscripten-finalize --parallel 2
+          "${build_dir}/bin/wasm-opt" --version
+          echo "EM_BINARYEN_ROOT=${build_dir}" >> "${GITHUB_ENV}"
+
       - name: Set up Go
         uses: ./.github/actions/setup-go
 
@@ -100,6 +123,19 @@ jobs:
           test -s "${RUNNER_TEMP}/browser-external.debug.wasm"
           ls -lh "${RUNNER_TEMP}"/browser-*.wasm
 
+      - name: Verify final browser DWARF
+        shell: bash
+        run: |
+          set -euo pipefail
+          for artifact in \
+            "${RUNNER_TEMP}/browser-embedded.wasm" \
+            "${RUNNER_TEMP}/browser-external.debug.wasm"
+          do
+            log="${artifact}.verify.log"
+            llvm-dwarfdump --verify "${artifact}" 2>&1 | tee "${log}"
+            grep -Fxq 'No errors.' "${log}"
+          done
+
       - name: Test headless Chrome Language Extension
         shell: bash
         run: |

.github/workflows/llgo.yml

@@ -132,6 +132,7 @@ jobs:
         run: |
           echo "Test lldb with llgo plugin on ${{matrix.os}} with LLVM ${{matrix.llvm}}"
           bash cmd/llgo/lldbtest/runtest.sh -v
+          bash cmd/llgo/debugtest/native/runtest.sh
 
       - name: DWARF standard tests
         if: ${{ startsWith(matrix.os, 'macos') && matrix.os != 'macos-15-intel' }}
@@ -409,3 +410,13 @@ jobs:
           grep -q 'external_debug_info' "$RUNNER_TEMP/runtime-external.sections"
           ! grep -q '\.debug_info' "$RUNNER_TEMP/runtime-external.sections"
           grep -q '\.debug_info' "$RUNNER_TEMP/runtime-external-debug.sections"
+
+          for artifact in \
+            "$RUNNER_TEMP/runtime-debug.wasm" \
+            "$RUNNER_TEMP/runtime-external.debug.wasm"
+          do
+            log="${artifact}.verify.log"
+            llvm-dwarfdump --verify --error-display=quiet \
+              "${artifact}" 2>&1 | tee "${log}"
+            grep -Fxq 'No errors.' "${log}"
+          done

cmd/llgo/debugtest/ACCEPTANCE.md

@@ -24,13 +24,20 @@ compatibility target. Exact commands live in these focused fixtures:
 - WASI: `cmd/llgo/debugtest/wasi`;
 - browser: `cmd/internal/browser` and `internal/browserdebug`.
 
+The browser lane uses Emscripten 4.0.21 and temporarily pins Binaryen commit
+`0c439cce601d5812209df1fc1188afe90100fca6`, which contains the DWARF range
+repair proposed in
+[WebAssembly/binaryen#8964](https://github.com/WebAssembly/binaryen/pull/8964).
+The pin can move back to an Emscripten-provided Binaryen release once that
+repair is upstream and included in the supported SDK.
+
 ## CI baseline
 
 | Gate | Workflow | What must be observed |
 | --- | --- | --- |
-| Native Darwin/Linux | `llgo.yml` | source breakpoints, scopes, locals/globals, runtime values, goroutine ownership/stacks, and raw non-LLGo fallback |
+| Native Darwin/Linux | `llgo.yml` | source breakpoints, scopes, locals/globals, runtime values, goroutine ownership/stacks, panic/fault source locations, optimized inline stepping, Go/C/Go frames, and raw non-LLGo fallback |
 | Emulated embedded | `targets.yml` | host ELF, GDB Remote and LLDB `gdb-remote`, source values/backtrace, identical flashed bytes with/without host DWARF, and verified retained DWARF |
-| WASI | `wasi-debug.yml` | final Wasm DWARF, Wasmtime guest stub, source breakpoint, parameter/local, call stack, and clean exit |
+| WASI | `wasi-debug.yml`, `llgo.yml` | strict final embedded/external Wasm DWARF verification, Wasmtime guest stub, source breakpoint, parameter/local, call stack, and clean exit |
 | Browser | `browser-debug.yml` | embedded and external DWARF, standard build identity, escaped sidecar URL, source remapping, all common runtime-layout categories, real LLGo Wasm registration, and no-extension fallback |
 
 Physical hardware is deliberately outside required PR CI. Its guarded script
@@ -58,21 +65,23 @@ Platform-specific limits remain explicit:
 - A missing external Wasm sidecar and a mismatched `build_id` fail before the
   browser launches. A consumer without the LLGo extension keeps raw/name
   section symbolication but does not get Go runtime presentation.
-- The current Asyncify-transformed browser runtime is accepted by Go's DWARF
-  reader and Chrome, but LLVM's final `llvm-dwarfdump --verify` still reports
-  overlapping/range-containment diagnostics. With Emscripten 4.0.21 and
-  Binaryen 125, relinking the exact same objects without Asyncify passes the
-  verifier across all compile units; Asyncify alone introduces invalid ranges
-  in both LLGo and Emscripten C-library DIEs. This matches Binaryen issue
-  [#6406](https://github.com/WebAssembly/binaryen/issues/6406). A source map
-  can recover source lines but cannot repair Wasm-local variable locations, so
-  it is not a substitute for this gate. This is a final-artifact blocker, not a
-  condition that the acceptance lane may suppress.
-
-Panic/trap source stops, optimized inline stepping, Go/host boundary frames,
-and clean final DWARF after every LTO/post-link transform remain required
-before the umbrella issue itself can be closed. Keep those failures visible in
-focused fixtures rather than weakening the validators.
+- Binaryen updates DWARF after Asyncify with a conservative range-topology
+  repair. Representable parent scopes are rebuilt from surviving children;
+  lost, reversed, or ambiguous scopes are reported as unavailable instead of
+  being assigned unrelated code. The browser lane runs
+  `llvm-dwarfdump --verify` against both the final embedded module and the
+  external DWARF sidecar after all post-link transforms. A verifier diagnostic
+  remains a hard failure; source maps are not accepted as a substitute for
+  variable, scope, or type DWARF.
+
+The native lane additionally stops explicit panic, integer division by zero,
+invalid memory, and a real host trap at their exact source locations. Its
+optimized fixture must preserve nested LLVM inline frames and step back to the
+physical caller, while its callback fixture preserves ordered Go/C/Go frames.
+Equivalent boundary coverage remains platform-specific. Clean final DWARF
+after every LTO/post-link transform is still required before the umbrella
+issue itself can be closed; keep transform failures visible in focused
+fixtures rather than weakening the validators.
 
 ## Artifact-size accounting
 

cmd/llgo/debugtest/native/README.md

@@ -0,0 +1,15 @@
+# Native fault and boundary debugging
+
+This fixture builds one final native LLGo artifact and drives it through stock
+LLDB. It verifies that explicit panic, integer division by zero, and invalid
+memory retain their exact Go source locations at the shared panic path; that a
+real host trap stops on both its C source and Go caller; and that a callback
+stack preserves ordered Go-to-C-to-Go boundary frames. A separate `-O2`
+artifact must expose nested LLVM inline frames and step from the inline leaf
+back to the non-inline caller's next source line.
+
+Run it after installing LLGo and LLDB 18 or newer:
+
+```sh
+bash cmd/llgo/debugtest/native/runtest.sh
+```