[llvm-commits] [llvm] r45567 - /llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp
Chris Lattner
sabre at nondot.org
Thu Jan 3 20:38:35 PST 2008
Author: lattner
Date: Thu Jan 3 22:38:35 2008
New Revision: 45567
URL: http://llvm.org/viewvc/llvm-project?rev=45567&view=rev
Log:
Change the builtin matcher to emit a decision tree, which should help out
the VC++ 'nesting depth' issue.
Modified:
llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp
Modified: llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp?rev=45567&r1=45566&r2=45567&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/IntrinsicEmitter.cpp Thu Jan 3 22:38:35 2008
@@ -338,6 +338,112 @@
OS << "#endif\n\n";
}
+/// EmitBuiltinComparisons - Emit comparisons to determine whether the specified
+/// sorted range of builtin names is equal to the current builtin. This breaks
+/// it down into a simple tree.
+///
+/// At this point, we know that all the builtins in the range have the same name
+/// for the first 'CharStart' characters. Only the end of the name needs to be
+/// discriminated.
+typedef std::map<std::string, std::string>::const_iterator StrMapIterator;
+static void EmitBuiltinComparisons(StrMapIterator Start, StrMapIterator End,
+ unsigned CharStart, unsigned Indent,
+ std::ostream &OS) {
+ if (Start == End) return; // empty range.
+
+ // Determine what, if anything, is the same about all these strings.
+ std::string CommonString = Start->first;
+ unsigned NumInRange = 0;
+ for (StrMapIterator I = Start; I != End; ++I, ++NumInRange) {
+ // Find the first character that doesn't match.
+ const std::string &ThisStr = I->first;
+ unsigned NonMatchChar = CharStart;
+ while (NonMatchChar < CommonString.size() &&
+ NonMatchChar < ThisStr.size() &&
+ CommonString[NonMatchChar] == ThisStr[NonMatchChar])
+ ++NonMatchChar;
+ // Truncate off pieces that don't match.
+ CommonString.resize(NonMatchChar);
+ }
+
+ // Just compare the rest of the string.
+ if (NumInRange == 1) {
+ if (CharStart != CommonString.size()) {
+ OS << std::string(Indent*2, ' ') << "if (!memcmp(BuiltinName";
+ if (CharStart) OS << "+" << CharStart;
+ OS << ", \"" << (CommonString.c_str()+CharStart) << "\", ";
+ OS << CommonString.size() - CharStart << "))\n";
+ ++Indent;
+ }
+ OS << std::string(Indent*2, ' ') << "IntrinsicID = Intrinsic::";
+ OS << Start->second << ";\n";
+ return;
+ }
+
+ // At this point, we potentially have a common prefix for these builtins, emit
+ // a check for this common prefix.
+ if (CommonString.size() != CharStart) {
+ OS << std::string(Indent*2, ' ') << "if (!memcmp(BuiltinName";
+ if (CharStart) OS << "+" << CharStart;
+ OS << ", \"" << (CommonString.c_str()+CharStart) << "\", ";
+ OS << CommonString.size()-CharStart << ")) {\n";
+
+ EmitBuiltinComparisons(Start, End, CommonString.size(), Indent+1, OS);
+ OS << std::string(Indent*2, ' ') << "}\n";
+ return;
+ }
+
+ // Output a switch on the character that differs across the set.
+ OS << std::string(Indent*2, ' ') << "switch (BuiltinName[" << CharStart
+ << "]) {";
+ if (CharStart)
+ OS << " // \"" << std::string(Start->first.begin(),
+ Start->first.begin()+CharStart) << "\"";
+ OS << "\n";
+
+ for (StrMapIterator I = Start; I != End; ) {
+ char ThisChar = I->first[CharStart];
+ OS << std::string(Indent*2, ' ') << "case '" << ThisChar << "':\n";
+ // Figure out the range that has this common character.
+ StrMapIterator NextChar = I;
+ for (++NextChar; NextChar != End && NextChar->first[CharStart] == ThisChar;
+ ++NextChar)
+ /*empty*/;
+ EmitBuiltinComparisons(I, NextChar, CharStart+1, Indent+1, OS);
+ OS << std::string(Indent*2, ' ') << " break;\n";
+ I = NextChar;
+ }
+ OS << std::string(Indent*2, ' ') << "}\n";
+}
+
+/// EmitTargetBuiltins - All of the builtins in the specified map are for the
+/// same target, and we already checked it.
+static void EmitTargetBuiltins(const std::map<std::string, std::string> &BIM,
+ std::ostream &OS) {
+ // Rearrange the builtins by length.
+ std::vector<std::map<std::string, std::string> > BuiltinsByLen;
+ BuiltinsByLen.reserve(100);
+
+ for (StrMapIterator I = BIM.begin(), E = BIM.end(); I != E; ++I) {
+ if (I->first.size() >= BuiltinsByLen.size())
+ BuiltinsByLen.resize(I->first.size()+1);
+ BuiltinsByLen[I->first.size()].insert(*I);
+ }
+
+ // Now that we have all the builtins by their length, emit a switch stmt.
+ OS << " switch (strlen(BuiltinName)) {\n";
+ OS << " default: break;\n";
+ for (unsigned i = 0, e = BuiltinsByLen.size(); i != e; ++i) {
+ if (BuiltinsByLen[i].empty()) continue;
+ OS << " case " << i << ":\n";
+ EmitBuiltinComparisons(BuiltinsByLen[i].begin(), BuiltinsByLen[i].end(),
+ 0, 3, OS);
+ OS << " break;\n";
+ }
+ OS << " }\n";
+}
+
+
void IntrinsicEmitter::
EmitIntrinsicToGCCBuiltinMap(const std::vector<CodeGenIntrinsic> &Ints,
std::ostream &OS) {
@@ -361,6 +467,7 @@
OS << "// in as TargetPrefix. The result is assigned to 'IntrinsicID'.\n";
OS << "#ifdef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN\n";
OS << " IntrinsicID = Intrinsic::not_intrinsic;\n";
+
// Note: this could emit significantly better code if we cared.
for (BIMTy::iterator I = BuiltinMap.begin(), E = BuiltinMap.end();I != E;++I){
OS << " ";
@@ -370,15 +477,8 @@
OS << "/* Target Independent Builtins */ ";
OS << "{\n";
- OS << " if (0);\n";
-
// Emit the comparisons for this target prefix.
- std::map<std::string, std::string> &BIM = I->second;
- for (std::map<std::string, std::string>::iterator J = BIM.begin(),
- E = BIM.end(); J != E; ++J) {
- OS << " else if (!strcmp(BuiltinName, \"" << J->first << "\"))\n";
- OS << " IntrinsicID = Intrinsic::" << J->second << ";\n";
- }
+ EmitTargetBuiltins(I->second, OS);
OS << " }\n";
}
OS << "#endif\n\n";
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