Add an OtherPreserved field to the CalleeSaved TableGen class.

This field specifies registers that are preserved across function calls,
but that should not be included in the generates SaveList array.

This can be used ot generate regmasks for architectures that save
registers through other means, like SPARC's register windows.

llvm-svn: 189084

include/llvm/Target/TargetCallingConv.td

@@ -143,4 +143,10 @@ class CallingConv<list<CCAction> actions> {
 /// returning from getCallPreservedMask().
 class CalleeSavedRegs<dag saves> {
   dag SaveList = saves;
+
+  // Registers that are also preserved across function calls, but should not be
+  // included in the generated FOO_SaveList array. These registers will be
+  // included in the FOO_RegMask bit mask. This can be used for registers that
+  // are saved automatically, like the SPARC register windows.
+  dag OtherPreserved;
 }

lib/Target/Sparc/SparcCallingConv.td

@@ -117,3 +117,9 @@ def CC_Sparc64 : CallingConv<[
   // arguments whether they are passed in registers or not.
   CCCustom<"CC_Sparc64_Full">
 ]>;
+
+// Callee-saved registers are handled by the register window mechanism.
+def CSR : CalleeSavedRegs<(add)> {
+  let OtherPreserved = (add (sequence "I%u", 0, 7),
+                            (sequence "L%u", 0, 7));
+}

lib/Target/Sparc/SparcRegisterInfo.cpp

@@ -40,8 +40,12 @@ SparcRegisterInfo::SparcRegisterInfo(SparcSubtarget &st)
 
 const uint16_t* SparcRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF)
                                                                          const {
-  static const uint16_t CalleeSavedRegs[] = { 0 };
-  return CalleeSavedRegs;
+  return CSR_SaveList;
+}
+
+const uint32_t*
+SparcRegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
+  return CSR_RegMask;
 }
 
 BitVector SparcRegisterInfo::getReservedRegs(const MachineFunction &MF) const {

lib/Target/Sparc/SparcRegisterInfo.h

@@ -32,6 +32,7 @@ struct SparcRegisterInfo : public SparcGenRegisterInfo {
 
   /// Code Generation virtual methods...
   const uint16_t *getCalleeSavedRegs(const MachineFunction *MF = 0) const;
+  const uint32_t* getCallPreservedMask(CallingConv::ID CC) const;
 
   BitVector getReservedRegs(const MachineFunction &MF) const;
 

utils/TableGen/RegisterInfoEmitter.cpp

@@ -1314,9 +1314,21 @@ RegisterInfoEmitter::runTargetDesc(raw_ostream &OS, CodeGenTarget &Target,
     OS << "0 };\n";
 
     // Emit the *_RegMask bit mask of call-preserved registers.
+    BitVector Covered = RegBank.computeCoveredRegisters(*Regs);
+
+    // Check for an optional OtherPreserved set.
+    // Add those registers to RegMask, but not to SaveList.
+    if (DagInit *OPDag =
+        dyn_cast<DagInit>(CSRSet->getValueInit("OtherPreserved"))) {
+      SetTheory::RecSet OPSet;
+      RegBank.getSets().evaluate(OPDag, OPSet, CSRSet->getLoc());
+      Covered |= RegBank.computeCoveredRegisters(
+        ArrayRef<Record*>(OPSet.begin(), OPSet.end()));
+    }
+
     OS << "static const uint32_t " << CSRSet->getName()
        << "_RegMask[] = { ";
-    printBitVectorAsHex(OS, RegBank.computeCoveredRegisters(*Regs), 32);
+    printBitVectorAsHex(OS, Covered, 32);
     OS << "};\n";
   }
   OS << "\n\n";