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DWARF: Fix debug lines in fannkuch -O0 #2611

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Merged
merged 6 commits into from
Jan 22, 2020
Merged

DWARF: Fix debug lines in fannkuch -O0 #2611

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abcb338
NEW Check function end first in debug_line, as in practice it seems L…
kripken Jan 19, 2020
63cdc0f
NEW Skip debug lines if the address already appear earlier [ci skip]
kripken Jan 22, 2020
ec03155
NEW Fix prologue in fannkuch -O0 [ci skip] DO THIS BEFORE RANGES
kripken Jan 20, 2020
f344792
fix
kripken Jan 22, 2020
016334c
fix
kripken Jan 22, 2020
0d93890
style
kripken Jan 22, 2020
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24 changes: 18 additions & 6 deletions src/wasm/wasm-debug.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -118,7 +118,6 @@ struct LineState {
uint32_t discriminator = 0;
bool isStmt;
bool basicBlock = false;
// XXX these two should be just prologue, epilogue?
bool prologueEnd = false;
bool epilogueBegin = false;
bool endSequence = false;
Expand Down Expand Up @@ -314,8 +313,12 @@ struct LineState {
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 item = {};
Expand Down Expand Up @@ -597,21 +600,32 @@ static void updateDebugLines(llvm::DWARFYAML::Data& data,
BinaryLocation newAddr = 0;
if (locationUpdater.hasOldExprAddr(oldAddr)) {
newAddr = locationUpdater.getNewExprAddr(oldAddr);
}
// Test for a function's end address first, as LLVM output appears to
// use 1-past-the-end-of-the-function as a location in that function,
// and not the next (but the first byte of the next function, which is
// ambiguously identical to that value, is used at least in low_pc).
else if (locationUpdater.hasOldFuncEndAddr(oldAddr)) {
newAddr = locationUpdater.getNewFuncEndAddr(oldAddr);
} else if (locationUpdater.hasOldFuncStartAddr(oldAddr)) {
newAddr = locationUpdater.getNewFuncStartAddr(oldAddr);
} else if (locationUpdater.hasOldFuncEndAddr(oldAddr)) {
newAddr = locationUpdater.getNewFuncEndAddr(oldAddr);
} else if (locationUpdater.hasOldExtraAddr(oldAddr)) {
newAddr = locationUpdater.getNewExtraAddr(oldAddr);
}
// TODO: last 'end' of a function
if (newAddr) {
// LLVM sometimes emits the same address more than once. We should
// probably investigate that.
if (newAddrInfo.count(newAddr)) {
continue;
}
newAddrs.push_back(newAddr);
assert(newAddrInfo.count(newAddr) == 0);
newAddrInfo.emplace(newAddr, state);
auto& updatedState = newAddrInfo.at(newAddr);
// The only difference is the address TODO other stuff?
updatedState.addr = newAddr;
// Reset relevant state.
state.resetAfterLine();
}
if (opcode.Opcode == 0 &&
opcode.SubOpcode == llvm::dwarf::DW_LNE_end_sequence) {
Expand Down Expand Up @@ -765,8 +779,6 @@ void writeDWARFSections(Module& wasm, const BinaryLocations& newLocations) {

updateCompileUnits(info, data, locationUpdater);

// TODO: Actually update, and remove sections we don't know how to update yet?

// Convert to binary sections.
auto newSections =
EmitDebugSections(data, false /* EmitFixups for debug_info */);
Expand Down
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