X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FPrologEpilogInserter.cpp;h=d3b0b11c705957eb2a720b6de1fd0d5e3727a186;hb=f9410141f703f4e8a6aba717617ef958249f6d13;hp=3106455850931defc66aa541e9a1c24491b15ff4;hpb=be680dcea6858c438c6615326ae1c098ff448ae1;p=oota-llvm.git

diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index 31064558509..d3b0b11c705 100644
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -35,12 +35,18 @@ using namespace llvm;
 namespace {
   struct VISIBILITY_HIDDEN PEI : public MachineFunctionPass {
     static char ID;
-    PEI() : MachineFunctionPass((intptr_t)&ID) {}
+    PEI() : MachineFunctionPass(&ID) {}
 
     const char *getPassName() const {
       return "Prolog/Epilog Insertion & Frame Finalization";
     }
 
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addPreservedID(MachineLoopInfoID);
+      AU.addPreservedID(MachineDominatorsID);
+      MachineFunctionPass::getAnalysisUsage(AU);
+    }
+
     /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
     /// frame indexes with appropriate references.
     ///
@@ -68,7 +74,7 @@ namespace {
 
       // Allow the target machine to make final modifications to the function
       // before the frame layout is finalized.
-      Fn.getTarget().getRegisterInfo()->processFunctionBeforeFrameFinalized(Fn);
+      TRI->processFunctionBeforeFrameFinalized(Fn);
 
       // Calculate actual frame offsets for all of the abstract stack objects...
       calculateFrameObjectOffsets(Fn);
@@ -313,11 +319,11 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
   // Loop over all of the stack objects, assigning sequential addresses...
   MachineFrameInfo *FFI = Fn.getFrameInfo();
 
-  unsigned MaxAlign = 0;
+  unsigned MaxAlign = FFI->getMaxAlignment();
 
   // Start at the beginning of the local area.
   // The Offset is the distance from the stack top in the direction
-  // of stack growth -- so it's always positive.
+  // of stack growth -- so it's always nonnegative.
   int64_t Offset = TFI.getOffsetOfLocalArea();
   if (StackGrowsDown)
     Offset = -Offset;
@@ -362,7 +368,8 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
       FFI->setObjectOffset(i, -Offset);        // Set the computed offset
     }
   } else {
-    for (unsigned i = MaxCSFrameIndex; i >= MinCSFrameIndex; --i) {
+    int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex;
+    for (int i = MaxCSFI; i >= MinCSFI ; --i) {
       unsigned Align = FFI->getObjectAlignment(i);
       // If the alignment of this object is greater than that of the stack, then
       // increase the stack alignment to match.
@@ -458,15 +465,20 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
   // Round up the size to a multiple of the alignment, but only if there are
   // calls or alloca's in the function.  This ensures that any calls to
   // subroutines have their stack frames suitable aligned.
+  // Also do this if we need runtime alignment of the stack.  In this case
+  // offsets will be relative to SP not FP; round up the stack size so this
+  // works.
   if (!RegInfo->targetHandlesStackFrameRounding() &&
-      (FFI->hasCalls() || FFI->hasVarSizedObjects())) {
+      (FFI->hasCalls() || FFI->hasVarSizedObjects() || 
+       (RegInfo->needsStackRealignment(Fn) &&
+        FFI->getObjectIndexEnd() != 0))) {
     // If we have reserved argument space for call sites in the function
     // immediately on entry to the current function, count it as part of the
     // overall stack size.
     if (RegInfo->hasReservedCallFrame(Fn))
       Offset += FFI->getMaxCallFrameSize();
 
-    unsigned AlignMask = TFI.getStackAlignment() - 1;
+    unsigned AlignMask = std::max(TFI.getStackAlignment(),MaxAlign) - 1;
     Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
   }
 
@@ -484,14 +496,16 @@ void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
 /// prolog and epilog code to the function.
 ///
 void PEI::insertPrologEpilogCode(MachineFunction &Fn) {
+  const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
+
   // Add prologue to the function...
-  Fn.getTarget().getRegisterInfo()->emitPrologue(Fn);
+  TRI->emitPrologue(Fn);
 
   // Add epilogue to restore the callee-save registers in each exiting block
   for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
     // If last instruction is a return instruction, add an epilogue
     if (!I->empty() && I->back().getDesc().isReturn())
-      Fn.getTarget().getRegisterInfo()->emitEpilogue(Fn, *I);
+      TRI->emitEpilogue(Fn, *I);
   }
 }
 
@@ -517,40 +531,67 @@ void PEI::replaceFrameIndices(MachineFunction &Fn) {
     for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
       MachineInstr *MI = I;
 
+      if (I->getOpcode() == TargetInstrInfo::DECLARE) {
+        // Ignore it.
+        ++I;
+        continue;
+      }
+
       if (I->getOpcode() == FrameSetupOpcode ||
           I->getOpcode() == FrameDestroyOpcode) {
-        // Remember how much SP has been adjustment to create the call frame.
+        // Remember how much SP has been adjusted to create the call
+        // frame.
         int Size = I->getOperand(0).getImm();
+
         if ((!StackGrowsDown && I->getOpcode() == FrameSetupOpcode) ||
             (StackGrowsDown && I->getOpcode() == FrameDestroyOpcode))
           Size = -Size;
+
         SPAdj += Size;
+
         MachineBasicBlock::iterator PrevI = prior(I);
         TRI.eliminateCallFramePseudoInstr(Fn, *BB, I);
+
         // Visit the instructions created by eliminateCallFramePseudoInstr().
         I = next(PrevI);
-        MI = NULL;
-      } else if (I->getOpcode() == TargetInstrInfo::DECLARE)
-        // Ignore it.
-        I++;
-      else {
-        I++;
-        for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
-          if (MI->getOperand(i).isFrameIndex()) {
-            // If this instruction has a FrameIndex operand, we need to use that
-            // target machine register info object to eliminate it.
-            TRI.eliminateFrameIndex(MI, SPAdj, RS);
-
-            // Revisit the instruction in full.  Some instructions (e.g. inline
-            // asm instructions) can have multiple frame indices.
-            --I;
-            MI = 0;
-            break;
-          }
+        continue;
       }
+
+      bool DoIncr = true;
+
+      for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
+        if (MI->getOperand(i).isFI()) {
+          // Some instructions (e.g. inline asm instructions) can have
+          // multiple frame indices and/or cause eliminateFrameIndex
+          // to insert more than one instruction. We need the register
+          // scavenger to go through all of these instructions so that
+          // it can update its register information. We keep the
+          // iterator at the point before insertion so that we can
+          // revisit them in full.
+          bool AtBeginning = (I == BB->begin());
+          if (!AtBeginning) --I;
+
+          // If this instruction has a FrameIndex operand, we need to
+          // use that target machine register info object to eliminate
+          // it.
+          TRI.eliminateFrameIndex(MI, SPAdj, RS);
+
+          // Reset the iterator if we were at the beginning of the BB.
+          if (AtBeginning) {
+            I = BB->begin();
+            DoIncr = false;
+          }
+
+          MI = 0;
+          break;
+        }
+
+      if (DoIncr) ++I;
+
       // Update register states.
       if (RS && MI) RS->forward(MI);
     }
+
     assert(SPAdj == 0 && "Unbalanced call frame setup / destroy pairs?");
   }
 }