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llvm-mc/AsmParser: Separate instruction ordering for ambiguity detection.

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- We want the ordering operation to be simple, since we run it on every
   match. The old ordering is also not a strict weak ordering when there are
   ambiguities, which makes MSVC unhappy.

 - While we are at it, detect all ambiguities instead of just the adjacent
   ones. There are actually 655, for X86.

llvm-svn: 78526
This commit is contained in:
Daniel Dunbar 2009-08-09 06:05:33 +00:00
parent 326491672e
commit 1d76f6d593
1 changed files with 47 additions and 38 deletions
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85
utils/TableGen/AsmMatcherEmitter.cpp
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@ -263,7 +263,7 @@ static bool IsAssemblerInstruction(const StringRef &Name,
DEBUG({
errs() << "warning: '" << Name << "': "
<< "ignoring instruction; tied operand '"
<< Tokens[i] << "', \n";
<< Tokens[i] << "'\n";
});
return false;
}
@ -368,36 +368,47 @@ struct InstructionInfo {
/// operator< - Compare two instructions.
bool operator<(const InstructionInfo &RHS) const {
// Order first by the number of operands (which is unambiguous).
if (Operands.size() != RHS.Operands.size())
return Operands.size() < RHS.Operands.size();
// Otherwise, order by lexicographic comparison of tokens and operand kinds
// (these can never be ambiguous).
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
if (Operands[i].Class->Kind != RHS.Operands[i].Class->Kind ||
Operands[i].Class->Kind == ClassInfo::Token)
if (*Operands[i].Class < *RHS.Operands[i].Class)
return true;
// Finally, order by the component wise comparison of operand classes. We
// don't want to rely on the lexigraphic ordering of elements, so we define
// only define the ordering when it is unambiguous. That is, when some pair
// compares less than and no pair compares greater than.
// Check that no pair compares greater than.
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
if (*RHS.Operands[i].Class < *Operands[i].Class)
return false;
// Otherwise, return true if some pair compares less than.
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
if (*Operands[i].Class < *RHS.Operands[i].Class)
return true;
return false;
}
/// CouldMatchAmiguouslyWith - Check whether this instruction could
/// ambiguously match the same set of operands as \arg RHS (without being a
/// strictly superior match).
bool CouldMatchAmiguouslyWith(const InstructionInfo &RHS) {
// The number of operands is unambiguous.
if (Operands.size() != RHS.Operands.size())
return false;
// Tokens and operand kinds are unambiguous (assuming a correct target
// specific parser).
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
if (Operands[i].Class->Kind != RHS.Operands[i].Class->Kind ||
Operands[i].Class->Kind == ClassInfo::Token)
if (*Operands[i].Class < *RHS.Operands[i].Class ||
*RHS.Operands[i].Class < *Operands[i].Class)
return false;
// Otherwise, this operand could commute if all operands are equivalent, or
// there is a pair of operands that compare less than and a pair that
// compare greater than.
bool HasLT = false, HasGT = false;
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (*Operands[i].Class < *RHS.Operands[i].Class)
HasLT = true;
if (*RHS.Operands[i].Class < *Operands[i].Class)
HasGT = true;
}
return !(HasLT ^ HasGT);
}
public:
void dump();
};
@ -991,23 +1002,21 @@ void AsmMatcherEmitter::run(raw_ostream &OS) {
// Check for ambiguous instructions.
unsigned NumAmbiguous = 0;
for (std::vector<InstructionInfo*>::const_iterator it =
Info.Instructions.begin(), ie = Info.Instructions.end() - 1;
it != ie;) {
InstructionInfo &II = **it;
++it;
InstructionInfo &Next = **it;
for (unsigned i = 0, e = Info.Instructions.size(); i != e; ++i) {
for (unsigned j = i + 1; j != e; ++j) {
InstructionInfo &A = *Info.Instructions[i];
InstructionInfo &B = *Info.Instructions[j];
if (!(II < Next)){
DEBUG_WITH_TYPE("ambiguous_instrs", {
errs() << "warning: ambiguous instruction match:\n";
II.dump();
errs() << "\nis incomparable with:\n";
Next.dump();
errs() << "\n\n";
});
++NumAmbiguous;
if (A.CouldMatchAmiguouslyWith(B)) {
DEBUG_WITH_TYPE("ambiguous_instrs", {
errs() << "warning: ambiguous instruction match:\n";
A.dump();
errs() << "\nis incomparable with:\n";
B.dump();
errs() << "\n\n";
});
++NumAmbiguous;
}
}
}
if (NumAmbiguous)