Change MRegisterDesc::AliasSet, TargetInstrDescriptor::ImplicitDefs

and TargetInstrDescriptor::ImplicitUses to always point to a null
terminated array and never be null. So there is no need to check for
pointer validity when iterating over those sets. Code that looked
like:

if (const unsigned* AS = TID.ImplicitDefs) {
  for (int i = 0; AS[i]; ++i) {
    // use AS[i]
  }
}

was changed to:

for (const unsigned* AS = TID.ImplicitDefs; *AS; ++AS) {
  // use *AS
}


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8960 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 10 insertions, 4 deletions

diff --git a/utils/TableGen/InstrInfoEmitter.cpp b/utils/TableGen/InstrInfoEmitter.cpp
index c794cd0441..7b64f922f6 100644
--- a/utils/TableGen/InstrInfoEmitter.cpp
+++ b/utils/TableGen/InstrInfoEmitter.cpp
@@ -65,6 +65,10 @@ void InstrInfoEmitter::run(std::ostream &OS) {
   std::vector<Record*> Instructions =
     Records.getAllDerivedDefinitions("Instruction");
   
+  // 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...
   for (unsigned i = 0, e = Instructions.size(); i != e; ++i) {
     Record *Inst = Instructions[i];
@@ -113,13 +117,13 @@ void InstrInfoEmitter::emitRecord(Record *R, unsigned Num, Record *InstrInfo,
   // Emit the implicit uses and defs lists...
   LI = R->getValueAsListInit("Uses");
   if (!LI->getSize())
-    OS << "0, ";
+    OS << "EmptyImpUses, ";
   else 
     OS << R->getName() << "ImpUses, ";
 
   LI = R->getValueAsListInit("Defs");
   if (!LI->getSize())
-    OS << "0 ";
+    OS << "EmptyImpDefs ";
   else 
     OS << R->getName() << "ImpDefs ";
 
diff --git a/utils/TableGen/RegisterInfoEmitter.cpp b/utils/TableGen/RegisterInfoEmitter.cpp
index af3efe3a9c..7652e67772 100644
--- a/utils/TableGen/RegisterInfoEmitter.cpp
+++ b/utils/TableGen/RegisterInfoEmitter.cpp
@@ -138,7 +138,7 @@ void RegisterInfoEmitter::run(std::ostream &OS) {
   std::vector<Record*> RegisterAliasesRecs =
     Records.getAllDerivedDefinitions("RegisterAliases");
   std::map<Record*, std::set<Record*> > RegisterAliases;
-  
+
   for (unsigned i = 0, e = RegisterAliasesRecs.size(); i != e; ++i) {
     Record *AS = RegisterAliasesRecs[i];
     Record *R = AS->getValueAsDef("Reg");
@@ -166,6 +166,8 @@ void RegisterInfoEmitter::run(std::ostream &OS) {
   if (!RegisterAliases.empty())
     OS << "\n\n  // Register Alias Sets...\n";
   
+  // Emit the empty alias list
+  OS << "  const unsigned Empty_AliasSet[] = { 0 };\n";
   // Loop over all of the registers which have aliases, emitting the alias list
   // to memory.
   for (std::map<Record*, std::set<Record*> >::iterator
@@ -192,7 +194,7 @@ void RegisterInfoEmitter::run(std::ostream &OS) {
     if (RegisterAliases.count(Reg))
       OS << Reg->getName() << "_AliasSet,\t";
     else
-      OS << "0,\t\t";
+      OS << "Empty_AliasSet,\t";
     OS << "0, 0 },\n";    
   }
   OS << "  };\n";      // End of register descriptors...