Add TableGen support for callee saved registers.

Targets can now add CalleeSavedRegs defs to their *CallingConv.td file.
TableGen will use this to create a *_SaveList array suitable for
returning from getCalleeSavedRegs() as well as a *_RegMask bit mask
suitable for returning from getCallPreservedMask().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148346 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 67 insertions, 0 deletions

diff --git a/include/llvm/Target/TargetCallingConv.td b/include/llvm/Target/TargetCallingConv.td
index 6da3ba1..a53ed29 100644
--- a/include/llvm/Target/TargetCallingConv.td
+++ b/include/llvm/Target/TargetCallingConv.td
@@ -133,3 +133,14 @@ class CCDelegateTo<CallingConv cc> : CCAction {
 class CallingConv<list<CCAction> actions> {
   list<CCAction> Actions = actions;
 }
+
+/// CalleeSavedRegs - A list of callee saved registers for a given calling
+/// convention.  The order of registers is used by PrologEpilogInsertion when
+/// allocation stack slots for saved registers.
+///
+/// For each CalleeSavedRegs def, TableGen will emit a FOO_SaveList array for
+/// returning from getCalleeSavedRegs(), and a FOO_RegMask bit mask suitable for
+/// returning from getCallPreservedMask().
+class CalleeSavedRegs<dag saves> {
+  dag SaveList = saves;
+}
diff --git a/utils/TableGen/CodeGenRegisters.cpp b/utils/TableGen/CodeGenRegisters.cpp
index 889acdd..89358c8 100644
--- a/utils/TableGen/CodeGenRegisters.cpp
+++ b/utils/TableGen/CodeGenRegisters.cpp
@@ -526,6 +526,7 @@ CodeGenRegisterClass::getSuperRegClasses(Record *SubIdx, BitVector &Out) const {
 CodeGenRegBank::CodeGenRegBank(RecordKeeper &Records) : Records(Records) {
   // Configure register Sets to understand register classes and tuples.
   Sets.addFieldExpander("RegisterClass", "MemberList");
+  Sets.addFieldExpander("CalleeSavedRegs", "SaveList");
   Sets.addExpander("RegisterTuples", new TupleExpander());
 
   // Read in the user-defined (named) sub-register indices.
@@ -991,3 +992,25 @@ CodeGenRegBank::getRegClassForRegister(Record *R) {
   }
   return FoundRC;
 }
+
+BitVector CodeGenRegBank::computeCoveredRegisters(ArrayRef<Record*> Regs) {
+  SetVector<CodeGenRegister*> Set;
+
+  // First add Regs with all sub-registers.
+  for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
+    CodeGenRegister *Reg = getReg(Regs[i]);
+    if (Set.insert(Reg))
+      // Reg is new, add all sub-registers.
+      // The pre-ordering is not important here.
+      Reg->addSubRegsPreOrder(Set);
+  }
+
+  // Second, find all super-registers that are completely covered by the set.
+  // FIXME: Implement CoveredBySubRegs bit.
+
+  // Convert to BitVector.
+  BitVector BV(Registers.size() + 1);
+  for (unsigned i = 0, e = Set.size(); i != e; ++i)
+    BV.set(Set[i]->EnumValue);
+  return BV;
+}
diff --git a/utils/TableGen/CodeGenRegisters.h b/utils/TableGen/CodeGenRegisters.h
index 1d1454c..6153fe5 100644
--- a/utils/TableGen/CodeGenRegisters.h
+++ b/utils/TableGen/CodeGenRegisters.h
@@ -320,6 +320,15 @@ namespace llvm {
     // If R1 is a sub-register of R2, Map[R1] is a subset of Map[R2].
     void computeOverlaps(std::map<const CodeGenRegister*,
                                   CodeGenRegister::Set> &Map);
+
+    // Compute the set of registers completely covered by the registers in Regs.
+    // The returned BitVector will have a bit set for each register in Regs,
+    // all sub-registers, and all super-registers that are covered by the
+    // registers in Regs.
+    //
+    // This is used to compute the mask of call-preserved registers from a list
+    // of callee-saves.
+    BitVector computeCoveredRegisters(ArrayRef<Record*> Regs);
   };
 }
 
diff --git a/utils/TableGen/RegisterInfoEmitter.cpp b/utils/TableGen/RegisterInfoEmitter.cpp
index 5fa2fe0..1263e3d 100644
--- a/utils/TableGen/RegisterInfoEmitter.cpp
+++ b/utils/TableGen/RegisterInfoEmitter.cpp
@@ -879,6 +879,30 @@ RegisterInfoEmitter::runTargetDesc(raw_ostream &OS, CodeGenTarget &Target,
 
   OS << "}\n\n";
 
+
+  // Emit CalleeSavedRegs information.
+  std::vector<Record*> CSRSets =
+    Records.getAllDerivedDefinitions("CalleeSavedRegs");
+  for (unsigned i = 0, e = CSRSets.size(); i != e; ++i) {
+    Record *CSRSet = CSRSets[i];
+    const SetTheory::RecVec *Regs = RegBank.getSets().expand(CSRSet);
+    assert(Regs && "Cannot expand CalleeSavedRegs instance");
+
+    // Emit the *_SaveList list of callee-saved registers.
+    OS << "static const unsigned " << CSRSet->getName()
+       << "_SaveList[] = { ";
+    for (unsigned r = 0, re = Regs->size(); r != re; ++r)
+      OS << getQualifiedName((*Regs)[r]) << ", ";
+    OS << "0 };\n";
+
+    // Emit the *_RegMask bit mask of call-preserved registers.
+    OS << "static const uint32_t " << CSRSet->getName()
+       << "_RegMask[] = { ";
+    printBitVectorAsHex(OS, RegBank.computeCoveredRegisters(*Regs), 32);
+    OS << "};\n";
+  }
+  OS << "\n\n";
+
   OS << "} // End llvm namespace \n";
   OS << "#endif // GET_REGINFO_TARGET_DESC\n\n";
 }