[llvm] r321987 - [X86] Remove side-effects from determineCalleeSaves

[Francis Visoiu Mistrih via llvm-commits]

Author: thegameg
Date: Mon Jan  8 02:46:05 2018
New Revision: 321987

URL: http://llvm.org/viewvc/llvm-project?rev=321987&view=rev
Log:
[X86] Remove side-effects from determineCalleeSaves

(Target)FrameLowering::determineCalleeSaves can be called multiple
times. I don't think it should have side-effects as creating stack
objects and setting global MachineFunctionInfo state as it is doing
today (in other back-ends as well).

This moves the creation of stack objects from determineCalleeSaves to
assignCalleeSavedSpillSlots.

Differential Revision: https://reviews.llvm.org/D41703

Modified:
    llvm/trunk/lib/Target/X86/X86FrameLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=321987&r1=321986&r2=321987&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Mon Jan  8 02:46:05 2018
@@ -1855,6 +1855,32 @@ bool X86FrameLowering::assignCalleeSaved
   unsigned CalleeSavedFrameSize = 0;
   int SpillSlotOffset = getOffsetOfLocalArea() + X86FI->getTCReturnAddrDelta();
 
+  int64_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
+
+  if (TailCallReturnAddrDelta < 0) {
+    // create RETURNADDR area
+    //   arg
+    //   arg
+    //   RETADDR
+    //   { ...
+    //     RETADDR area
+    //     ...
+    //   }
+    //   [EBP]
+    MFI.CreateFixedObject(-TailCallReturnAddrDelta,
+                           TailCallReturnAddrDelta - SlotSize, true);
+  }
+
+  // Spill the BasePtr if it's used.
+  if (this->TRI->hasBasePointer(MF)) {
+    // Allocate a spill slot for EBP if we have a base pointer and EH funclets.
+    if (MF.hasEHFunclets()) {
+      int FI = MFI.CreateSpillStackObject(SlotSize, SlotSize);
+      X86FI->setHasSEHFramePtrSave(true);
+      X86FI->setSEHFramePtrSaveIndex(FI);
+    }
+  }
+
   if (hasFP(MF)) {
     // emitPrologue always spills frame register the first thing.
     SpillSlotOffset -= SlotSize;
@@ -2060,36 +2086,9 @@ void X86FrameLowering::determineCalleeSa
                                             RegScavenger *RS) const {
   TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
 
-  MachineFrameInfo &MFI = MF.getFrameInfo();
-
-  X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
-  int64_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
-
-  if (TailCallReturnAddrDelta < 0) {
-    // create RETURNADDR area
-    //   arg
-    //   arg
-    //   RETADDR
-    //   { ...
-    //     RETADDR area
-    //     ...
-    //   }
-    //   [EBP]
-    MFI.CreateFixedObject(-TailCallReturnAddrDelta,
-                           TailCallReturnAddrDelta - SlotSize, true);
-  }
-
   // Spill the BasePtr if it's used.
-  if (TRI->hasBasePointer(MF)) {
+  if (TRI->hasBasePointer(MF))
     SavedRegs.set(TRI->getBaseRegister());
-
-    // Allocate a spill slot for EBP if we have a base pointer and EH funclets.
-    if (MF.hasEHFunclets()) {
-      int FI = MFI.CreateSpillStackObject(SlotSize, SlotSize);
-      X86FI->setHasSEHFramePtrSave(true);
-      X86FI->setSEHFramePtrSaveIndex(FI);
-    }
-  }
 }
 
 static bool