When emitting implicit use/def lists, only emit each unique list once. Though

LLVM is able to merge identical static const globals, GCC isn't, and this caused
some bloat in the generated data.  This has a marginal effect on PPC, shrinking
the implicit sets from 10->4, but shrinks X86 from 179 to 23, a much bigger
reduction.

This should speed up the register allocator as well by reducing the dcache
footprint for this static data.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22879 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 48 insertions, 21 deletions

diff --git a/utils/TableGen/InstrInfoEmitter.cpp b/utils/TableGen/InstrInfoEmitter.cpp
index 2b2a81c1f3..7dc13bc9ce 100644
--- a/utils/TableGen/InstrInfoEmitter.cpp
+++ b/utils/TableGen/InstrInfoEmitter.cpp
@@ -46,14 +46,21 @@ void InstrInfoEmitter::runEnums(std::ostream &OS) {
   OS << "} // End llvm namespace \n";
 }
 
-void InstrInfoEmitter::printDefList(ListInit *LI, const std::string &Name,
-                                    std::ostream &OS) const {
-  OS << "static const unsigned " << Name << "[] = { ";
-  for (unsigned j = 0, e = LI->getSize(); j != e; ++j)
-    if (DefInit *DI = dynamic_cast<DefInit*>(LI->getElement(j)))
-      OS << getQualifiedName(DI->getDef()) << ", ";
+static std::vector<Record*> GetDefList(ListInit *LI, const std::string &Name) {
+  std::vector<Record*> Result;
+  for (unsigned i = 0, e = LI->getSize(); i != e; ++i)
+    if (DefInit *DI = dynamic_cast<DefInit*>(LI->getElement(i)))
+      Result.push_back(DI->getDef());
     else
       throw "Illegal value in '" + Name + "' list!";
+  return Result;
+}
+
+void InstrInfoEmitter::printDefList(const std::vector<Record*> &Uses,
+                                    unsigned Num, std::ostream &OS) const {
+  OS << "static const unsigned ImplicitList" << Num << "[] = { ";
+  for (unsigned i = 0, e = Uses.size(); i != e; ++i)
+    OS << getQualifiedName(Uses[i]) << ", ";
   OS << "0 };\n";
 }
 
@@ -69,34 +76,50 @@ void InstrInfoEmitter::run(std::ostream &OS) {
   Record *PHI = InstrInfo->getValueAsDef("PHIInst");
 
   // Emit empty implicit uses and defs lists
-  OS << "static const unsigned EmptyImpUses[] = { 0 };\n"
-     << "static const unsigned EmptyImpDefs[] = { 0 };\n";
-
-  // Emit all of the instruction's implicit uses and defs...
+  OS << "static const unsigned EmptyImpList[] = { 0 };\n";
+
+  // Keep track of all of the def lists we have emitted already.
+  std::map<std::vector<Record*>, unsigned> EmittedLists;
+  std::map<ListInit*, unsigned> ListNumbers;
+  unsigned ListNumber = 0;
+ 
+  // Emit all of the instruction's implicit uses and defs.
   for (CodeGenTarget::inst_iterator II = Target.inst_begin(),
          E = Target.inst_end(); II != E; ++II) {
     Record *Inst = II->second.TheDef;
     ListInit *LI = Inst->getValueAsListInit("Uses");
-    if (LI->getSize()) printDefList(LI, Inst->getName()+"ImpUses", OS);
+    if (LI->getSize()) {
+      std::vector<Record*> Uses = GetDefList(LI, Inst->getName());
+      unsigned &IL = EmittedLists[Uses];
+      if (!IL) printDefList(Uses, IL = ++ListNumber, OS);
+      ListNumbers[LI] = IL;
+    }
     LI = Inst->getValueAsListInit("Defs");
-    if (LI->getSize()) printDefList(LI, Inst->getName()+"ImpDefs", OS);
+    if (LI->getSize()) {
+      std::vector<Record*> Uses = GetDefList(LI, Inst->getName());
+      unsigned &IL = EmittedLists[Uses];
+      if (!IL) printDefList(Uses, IL = ++ListNumber, OS);
+      ListNumbers[LI] = IL;
+    }
   }
 
   OS << "\nstatic const TargetInstrDescriptor " << TargetName
      << "Insts[] = {\n";
-  emitRecord(Target.getPHIInstruction(), 0, InstrInfo, OS);
+  emitRecord(Target.getPHIInstruction(), 0, InstrInfo, ListNumbers, OS);
 
   unsigned i = 0;
   for (CodeGenTarget::inst_iterator II = Target.inst_begin(),
          E = Target.inst_end(); II != E; ++II)
     if (II->second.TheDef != PHI)
-      emitRecord(II->second, ++i, InstrInfo, OS);
+      emitRecord(II->second, ++i, InstrInfo, ListNumbers, OS);
   OS << "};\n";
   OS << "} // End llvm namespace \n";
 }
 
 void InstrInfoEmitter::emitRecord(const CodeGenInstruction &Inst, unsigned Num,
-                                  Record *InstrInfo, std::ostream &OS) {
+                                  Record *InstrInfo,
+                                  std::map<ListInit*, unsigned> &ListNumbers,
+                                  std::ostream &OS) {
   OS << "  { \"";
   if (Inst.Name.empty())
     OS << Inst.TheDef->getName();
@@ -134,15 +157,15 @@ void InstrInfoEmitter::emitRecord(const CodeGenInstruction &Inst, unsigned Num,
   // Emit the implicit uses and defs lists...
   LI = Inst.TheDef->getValueAsListInit("Uses");
   if (!LI->getSize())
-    OS << "EmptyImpUses, ";
+    OS << "EmptyImpList, ";
   else
-    OS << Inst.TheDef->getName() << "ImpUses, ";
+    OS << "ImplicitList" << ListNumbers[LI] << ", ";
 
   LI = Inst.TheDef->getValueAsListInit("Defs");
   if (!LI->getSize())
-    OS << "EmptyImpDefs ";
+    OS << "EmptyImpList ";
   else
-    OS << Inst.TheDef->getName() << "ImpDefs ";
+    OS << "ImplicitList" << ListNumbers[LI] << " ";
 
   OS << " },  // Inst #" << Num << " = " << Inst.TheDef->getName() << "\n";
 }
diff --git a/utils/TableGen/InstrInfoEmitter.h b/utils/TableGen/InstrInfoEmitter.h
index 005fd3810b..8b516f1978 100644
--- a/utils/TableGen/InstrInfoEmitter.h
+++ b/utils/TableGen/InstrInfoEmitter.h
@@ -16,6 +16,8 @@
 #define INSTRINFO_EMITTER_H
 
 #include "TableGenBackend.h"
+#include <vector>
+#include <map>
 
 namespace llvm {
 
@@ -35,10 +37,12 @@ public:
   // runEnums - Print out enum values for all of the instructions.
   void runEnums(std::ostream &OS);
 private:
-  void printDefList(ListInit *LI, const std::string &Name,
+  void printDefList(const std::vector<Record*> &Uses, unsigned Num,
                     std::ostream &OS) const;
   void emitRecord(const CodeGenInstruction &Inst, unsigned Num,
-                  Record *InstrInfo, std::ostream &OS);
+                  Record *InstrInfo, 
+                  std::map<ListInit*, unsigned> &ListNumbers,
+                  std::ostream &OS);
   void emitShiftedValue(Record *R, StringInit *Val, IntInit *Shift,
                         std::ostream &OS);
 };