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[AsmWriter] Ensure getMnemonic doesn't return invalid pointers #75783

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Merged
merged 4 commits into from
Dec 20, 2023
Merged

[AsmWriter] Ensure getMnemonic doesn't return invalid pointers #75783

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62f4b5d
[AsmWriter] Ensure getMnemonic doesn't return invalid pointers
pratlucas Dec 18, 2023
b048817
Merge branch 'llvm:main' into main
pratlucas Dec 18, 2023
1326609
fixup! [AsmWriter] Ensure getMnemonic doesn't return invalid pointers
pratlucas Dec 18, 2023
e3a4ee8
Merge branch 'llvm:main' into main
pratlucas Dec 19, 2023
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5 changes: 4 additions & 1 deletion llvm/lib/MC/MCAsmStreamer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -154,7 +154,10 @@ class MCAsmStreamer final : public MCStreamer {
void emitGNUAttribute(unsigned Tag, unsigned Value) override;

StringRef getMnemonic(MCInst &MI) override {
return InstPrinter->getMnemonic(&MI).first;
auto [Ptr, Bits] = InstPrinter->getMnemonic(&MI);
assert((Bits != 0 || Ptr == nullptr) &&
"Invalid char pointer for instruction with no mnemonic");
return Ptr;
}

void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
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4 changes: 4 additions & 0 deletions llvm/utils/TableGen/AsmWriterEmitter.cpp
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Expand Up @@ -438,6 +438,10 @@ void AsmWriterEmitter::EmitGetMnemonic(
O << " // Emit the opcode for the instruction.\n";
O << BitsString;

// Make sure we don't return an invalid pointer if bits is 0
O << " if (Bits == 0)\n"
" return {nullptr, Bits};\n";

// Return mnemonic string and bits.
O << " return {AsmStrs+(Bits & " << (1 << AsmStrBits) - 1
<< ")-1, Bits};\n\n";
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