PrologEpilogInserter: Rewrite API to determine callee save regsiters.

[oota-llvm.git] / lib / CodeGen / PrologEpilogInserter.cpp

diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index 7e162332de6ff5de879593010b0e5a64a4bf7203..6ca69a12429785a547a0993792a59117a5dd2cfe 100644 (file)
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -82,7 +82,8 @@ private:
 
   void calculateSets(MachineFunction &Fn);
   void calculateCallsInformation(MachineFunction &Fn);
-  void calculateCalleeSavedRegisters(MachineFunction &Fn);
+  void assignCalleeSavedSpillSlots(MachineFunction &Fn,
+                                   const BitVector &SavedRegs);
   void insertCSRSpillsAndRestores(MachineFunction &Fn);
   void calculateFrameObjectOffsets(MachineFunction &Fn);
   void replaceFrameIndices(MachineFunction &Fn);
@@ -183,13 +184,12 @@ bool PEI::runOnMachineFunction(MachineFunction &Fn) {
   // instructions.
   calculateCallsInformation(Fn);
 
-  // Allow the target machine to make some adjustments to the function
-  // e.g. UsedPhysRegs before calculateCalleeSavedRegisters.
-  TFI->processFunctionBeforeCalleeSavedScan(Fn, RS);
+  // Determine which of the registers in the callee save list should be saved.
+  BitVector SavedRegs;
+  TFI->determineCalleeSaves(Fn, SavedRegs, RS);
 
-  // Scan the function for modified callee saved registers and insert spill code
-  // for any callee saved registers that are modified.
-  calculateCalleeSavedRegisters(Fn);
+  // Insert spill code for any callee saved registers that are modified.
+  assignCalleeSavedSpillSlots(Fn, SavedRegs);
 
   // Determine placement of CSR spill/restore code:
   // place all spills in the entry block, all restores in return blocks.
@@ -295,39 +295,27 @@ void PEI::calculateCallsInformation(MachineFunction &Fn) {
   }
 }
 
-
-/// calculateCalleeSavedRegisters - Scan the function for modified callee saved
-/// registers.
-void PEI::calculateCalleeSavedRegisters(MachineFunction &F) {
-  const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
-  const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
-  MachineFrameInfo *MFI = F.getFrameInfo();
-
-  // Get the callee saved register list...
-  const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
-
+void PEI::assignCalleeSavedSpillSlots(MachineFunction &F,
+                                      const BitVector &SavedRegs) {
   // These are used to keep track the callee-save area. Initialize them.
   MinCSFrameIndex = INT_MAX;
   MaxCSFrameIndex = 0;
 
-  // Early exit for targets which have no callee saved registers.
-  if (!CSRegs || CSRegs[0] == 0)
+  if (SavedRegs.empty())
     return;
 
-  // In Naked functions we aren't going to save any registers.
-  if (F.getFunction()->hasFnAttribute(Attribute::Naked))
-    return;
+  const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
+  const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
 
   std::vector<CalleeSavedInfo> CSI;
   for (unsigned i = 0; CSRegs[i]; ++i) {
     unsigned Reg = CSRegs[i];
-    // Functions which call __builtin_unwind_init get all their registers saved.
-    if (F.getRegInfo().isPhysRegUsed(Reg) || F.getMMI().callsUnwindInit()) {
-      // If the reg is modified, save it!
+    if (SavedRegs.test(Reg))
       CSI.push_back(CalleeSavedInfo(Reg));
-    }
   }
 
+  const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
+  MachineFrameInfo *MFI = F.getFrameInfo();
   if (!TFI->assignCalleeSavedSpillSlots(F, RegInfo, CSI)) {
     // If target doesn't implement this, use generic code.