Add DWARF line table parser for source-level backtraces#329
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Parse DWARF .debug_line, .debug_info, .debug_abbrev, and .debug_ranges sections from WASM custom sections to resolve code addresses to source file/line/column locations. Used by Caller.captureBacktrace() to provide source-level information in stack traces. Key components: - DWARFLineTable: parses DWARF v4/v5 line number programs with CU-aware resolution using .debug_info address ranges - Code section offset conversion between file-level and DWARF addresses - binaryOffsetCorrection in Translator to fix buffer-relative offsets - Backtrace.Symbol.sourceLocation for resolved source locations - Precise line resolution via instruction mapping with function-start fallback - Translator fix from expose-debugging-api for folded instruction mapping - codeSectionStart exposed via ParsingPayload.codeSection - 13 unit tests for the DWARF parser Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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There's ongoing work on offline symbolication for Swift on other platforms. If we could agree on a format that WasmKit outputs, maybe the symbolicator could accept that and we wouldn't need DWARF parsing in WasmKit at all
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Could be optional of course, but handy during debugging. Still need something to decode the translated PC values to correct offsets that can be used offline. I don't believe the current PC values would work.
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I'd be happy to adjust values to whatever symbolicator is expecting. Probably also need to align WasmKit with output from other Wasm runtimes so that the symbolicator can expect consistent input.
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Looking at the failing unit tests now. |
This was polluting iseqToWasm, and breaking a debugger test.
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Parse DWARF .debug_line, .debug_info, .debug_abbrev, and .debug_ranges sections from WASM custom sections to resolve code addresses to source file/line/column locations. Used by Caller.captureBacktrace() to provide source-level information in stack traces.
Key components: