From af78d7a3dfc5fd7f0a983c0faa4a4cffeaa352d8 Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Fri, 23 Aug 2013 02:25:47 +0000
Subject: [PATCH] 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 |  6 ++++++
 lib/Target/Sparc/SparcCallingConv.td     |  6 ++++++
 lib/Target/Sparc/SparcRegisterInfo.cpp   |  8 ++++++--
 lib/Target/Sparc/SparcRegisterInfo.h     |  1 +
 utils/TableGen/RegisterInfoEmitter.cpp   | 14 +++++++++++++-
 5 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/include/llvm/Target/TargetCallingConv.td b/include/llvm/Target/TargetCallingConv.td
index a53ed29f1ec..c1bef28652e 100644
--- a/include/llvm/Target/TargetCallingConv.td
+++ b/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;
 }
diff --git a/lib/Target/Sparc/SparcCallingConv.td b/lib/Target/Sparc/SparcCallingConv.td
index a181bcf3d26..181165d6ddd 100644
--- a/lib/Target/Sparc/SparcCallingConv.td
+++ b/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));
+}
diff --git a/lib/Target/Sparc/SparcRegisterInfo.cpp b/lib/Target/Sparc/SparcRegisterInfo.cpp
index dc97f06b7ca..0b0fe2d4fe8 100644
--- a/lib/Target/Sparc/SparcRegisterInfo.cpp
+++ b/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 {
diff --git a/lib/Target/Sparc/SparcRegisterInfo.h b/lib/Target/Sparc/SparcRegisterInfo.h
index 6b77d4efa21..ae056cdcf29 100644
--- a/lib/Target/Sparc/SparcRegisterInfo.h
+++ b/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;
 
diff --git a/utils/TableGen/RegisterInfoEmitter.cpp b/utils/TableGen/RegisterInfoEmitter.cpp
index 731dccf75e8..9a30e159be4 100644
--- a/utils/TableGen/RegisterInfoEmitter.cpp
+++ b/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";