diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/wasm/wasm-debug.cpp | 70 |
1 files changed, 43 insertions, 27 deletions
diff --git a/src/wasm/wasm-debug.cpp b/src/wasm/wasm-debug.cpp index 20c5dfb62..4181b06f2 100644 --- a/src/wasm/wasm-debug.cpp +++ b/src/wasm/wasm-debug.cpp @@ -123,11 +123,17 @@ struct LineState { bool basicBlock = false; bool prologueEnd = false; bool epilogueBegin = false; - bool endSequence = false; + // Each instruction is part of a sequence, all of which get the same ID. The + // order within a sequence may change if binaryen reorders things, which means + // that we can't track the end_sequence location and assume it is at the end - + // we must track sequences and then emit an end for each one. + // -1 is an invalid marker value (note that this assumes we can fit all ids + // into just under 32 bits). + uint32_t sequenceId = -1; LineState(const LineState& other) = default; - LineState(const llvm::DWARFYAML::LineTable& table) - : isStmt(table.DefaultIsStmt) {} + LineState(const llvm::DWARFYAML::LineTable& table, uint32_t sequenceId) + : isStmt(table.DefaultIsStmt), sequenceId(sequenceId) {} LineState& operator=(const LineState& other) = default; @@ -143,7 +149,6 @@ struct LineState { break; } case llvm::dwarf::DW_LNE_end_sequence: { - endSequence = true; return true; } case llvm::dwarf::DW_LNE_set_discriminator: { @@ -241,17 +246,17 @@ struct LineState { } bool needToEmit() { - // Zero values imply we can ignore this line, unless it has something - // special we must emit. + // Zero values imply we can ignore this line. // https://github.com/WebAssembly/debugging/issues/9#issuecomment-567720872 - return (line != 0 && addr != 0) || endSequence; + return line != 0 && addr != 0; } // Given an old state, emit the diff from it to this state into a new line // table entry (that will be emitted in the updated DWARF debug line section). void emitDiff(const LineState& old, std::vector<llvm::DWARFYAML::LineTableOpcode>& newOpcodes, - const llvm::DWARFYAML::LineTable& table) { + const llvm::DWARFYAML::LineTable& table, + bool endSequence) const { bool useSpecial = false; if (addr != old.addr || line != old.line) { // Try to use a special opcode TODO @@ -299,8 +304,7 @@ struct LineState { assert(basicBlock); newOpcodes.push_back(makeItem(llvm::dwarf::DW_LNS_set_basic_block)); } - if (prologueEnd != old.prologueEnd) { - assert(prologueEnd); + if (prologueEnd) { newOpcodes.push_back(makeItem(llvm::dwarf::DW_LNS_set_prologue_end)); } if (epilogueBegin != old.epilogueBegin) { @@ -314,27 +318,25 @@ struct LineState { if (endSequence) { // len = 1 (subopcode) newOpcodes.push_back(makeItem(llvm::dwarf::DW_LNE_end_sequence, 1)); - // Reset the state. - *this = LineState(table); } else { newOpcodes.push_back(makeItem(llvm::dwarf::DW_LNS_copy)); } } - resetAfterLine(); } // Some flags are automatically reset after each debug line. void resetAfterLine() { prologueEnd = false; } private: - llvm::DWARFYAML::LineTableOpcode makeItem(llvm::dwarf::LineNumberOps opcode) { + llvm::DWARFYAML::LineTableOpcode + makeItem(llvm::dwarf::LineNumberOps opcode) const { llvm::DWARFYAML::LineTableOpcode item = {}; item.Opcode = opcode; return item; } llvm::DWARFYAML::LineTableOpcode - makeItem(llvm::dwarf::LineNumberExtendedOps opcode, uint64_t len) { + makeItem(llvm::dwarf::LineNumberExtendedOps opcode, uint64_t len) const { auto item = makeItem(llvm::dwarf::LineNumberOps(0)); // All the length after the len field itself, including the subopcode // (1 byte). @@ -626,8 +628,9 @@ struct LocationUpdater { static void updateDebugLines(llvm::DWARFYAML::Data& data, LocationUpdater& locationUpdater) { for (auto& table : data.DebugLines) { + uint32_t sequenceId = 0; // Parse the original opcodes and emit new ones. - LineState state(table); + LineState state(table, sequenceId); // All the addresses we need to write out. std::vector<BinaryLocation> newAddrs; std::unordered_map<BinaryLocation, LineState> newAddrInfo; @@ -645,7 +648,7 @@ static void updateDebugLines(llvm::DWARFYAML::Data& data, omittingRange = true; } if (omittingRange) { - state = LineState(table); + state = LineState(table, sequenceId); continue; } // An expression may not exist for this line table item, if we optimized @@ -666,7 +669,7 @@ static void updateDebugLines(llvm::DWARFYAML::Data& data, } else if (locationUpdater.hasOldDelimiter(oldAddr)) { newAddr = locationUpdater.getNewDelimiter(oldAddr); } - if (newAddr) { + if (newAddr && state.needToEmit()) { // LLVM sometimes emits the same address more than once. We should // probably investigate that. if (newAddrInfo.count(newAddr)) { @@ -682,7 +685,11 @@ static void updateDebugLines(llvm::DWARFYAML::Data& data, } if (opcode.Opcode == 0 && opcode.SubOpcode == llvm::dwarf::DW_LNE_end_sequence) { - state = LineState(table); + sequenceId++; + // We assume the number of sequences can fit in 32 bits, and -1 is + // an invalid value. + assert(sequenceId != uint32_t(-1)); + state = LineState(table, sequenceId); } } } @@ -692,15 +699,24 @@ static void updateDebugLines(llvm::DWARFYAML::Data& data, // Emit a new line table. { std::vector<llvm::DWARFYAML::LineTableOpcode> newOpcodes; - LineState state(table); - for (BinaryLocation addr : newAddrs) { - LineState oldState(state); - state = newAddrInfo.at(addr); - if (state.needToEmit()) { - state.emitDiff(oldState, newOpcodes, table); - } else { - state = oldState; + for (size_t i = 0; i < newAddrs.size(); i++) { + LineState state = newAddrInfo.at(newAddrs[i]); + assert(state.needToEmit()); + LineState lastState(table, -1); + if (i != 0) { + lastState = newAddrInfo.at(newAddrs[i - 1]); + // If the last line is in another sequence, clear the old state, as + // there is nothing to diff to. + if (lastState.sequenceId != state.sequenceId) { + lastState = LineState(table, -1); + } } + // This line ends a sequence if there is no next line after it, or if + // the next line is in a different sequence. + bool endSequence = + i + 1 == newAddrs.size() || + newAddrInfo.at(newAddrs[i + 1]).sequenceId != state.sequenceId; + state.emitDiff(lastState, newOpcodes, table, endSequence); } table.Opcodes.swap(newOpcodes); } |