Optional args are no longer allocated as they are discovered.

(This can be improved to avoid making the initial pass over the method.)
Also, ensure automatic vars and reg. spills areas are not extended
if their sizes are used for computing some other offset.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2310 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 51 deletions

diff --git a/lib/CodeGen/MachineFunction.cpp b/lib/CodeGen/MachineFunction.cpp
index bb52ef298e..06e0666ec8 100644
--- a/lib/CodeGen/MachineFunction.cpp
+++ b/lib/CodeGen/MachineFunction.cpp
@@ -1,10 +1,10 @@
-//===-- MachineCodeForFunction.cpp ------------------------------------------=//
+//===-- MachineCodeForMethod.cpp -------------------------------------------=//
 // 
 // Purpose:
 //   Collect native machine code information for a function.
 //   This allows target-specific information about the generated code
 //   to be stored with each function.
-//===----------------------------------------------------------------------===//
+//===---------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/MachineCodeForMethod.h"
 #include "llvm/CodeGen/MachineInstr.h"  // For debug output
@@ -55,7 +55,8 @@ MachineCodeForMethod::get(const Function *F)
 }
 
 static unsigned
-ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F)
+ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F,
+                           unsigned &maxOptionalNumArgs)
 {
   const MachineFrameInfo& frameInfo = target.getFrameInfo();
   
@@ -68,7 +69,7 @@ ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F)
         if (CallInst *callInst = dyn_cast<CallInst>(*I))
           {
             unsigned int numOperands = callInst->getNumOperands() - 1;
-            int numExtra = (int)numOperands-frameInfo.getNumFixedOutgoingArgs();
+            int numExtra =(int)numOperands-frameInfo.getNumFixedOutgoingArgs();
             if (numExtra <= 0)
               continue;
             
@@ -91,6 +92,9 @@ ComputeMaxOptionalArgsSize(const TargetMachine& target, const Function *F)
             
             if (maxSize < sizeForThisCall)
               maxSize = sizeForThisCall;
+            
+            if (((int) maxOptionalNumArgs) < numExtra)
+              maxOptionalNumArgs = (unsigned) numExtra;
           }
     }
   
@@ -121,12 +125,14 @@ SizeToAlignment(unsigned int size, const TargetMachine& target)
 MachineCodeForMethod::MachineCodeForMethod(const Function *F,
                                            const TargetMachine& target)
   : Annotation(MCFM_AID),
-    method(F), compiledAsLeaf(false), staticStackSize(0),
+    method(F), staticStackSize(0),
     automaticVarsSize(0), regSpillsSize(0),
-    currentOptionalArgsSize(0), maxOptionalArgsSize(0),
-    currentTmpValuesSize(0), maxTmpValuesSize(0)
+    maxOptionalArgsSize(0), maxOptionalNumArgs(0),
+    currentTmpValuesSize(0), maxTmpValuesSize(0), compiledAsLeaf(false),
+    spillsAreaFrozen(false), automaticVarsAreaFrozen(false)
 {
-  maxOptionalArgsSize = ComputeMaxOptionalArgsSize(target, method);
+  maxOptionalArgsSize = ComputeMaxOptionalArgsSize(target, method,
+                                                   maxOptionalNumArgs);
   staticStackSize = maxOptionalArgsSize
                     + target.getFrameInfo().getMinStackFrameSize();
 }
@@ -172,6 +178,10 @@ MachineCodeForMethod::allocateLocalVar(const TargetMachine& target,
                                        const Value* val,
                                        unsigned int sizeToUse = 0)
 {
+  assert(! automaticVarsAreaFrozen &&
+         "Size of auto vars area has been used to compute an offset so "
+         "no more automatic vars should be allocated!");
+  
   // Check if we've allocated a stack slot for this value already
   // 
   int offset = getOffset(val);
@@ -190,6 +200,10 @@ int
 MachineCodeForMethod::allocateSpilledValue(const TargetMachine& target,
                                            const Type* type)
 {
+  assert(! spillsAreaFrozen &&
+         "Size of reg spills area has been used to compute an offset so "
+         "no more register spill slots should be allocated!");
+  
   unsigned int size  = target.findOptimalStorageSize(type);
   unsigned char align = target.DataLayout.getTypeAlignment(type);
   
@@ -215,49 +229,6 @@ MachineCodeForMethod::allocateSpilledValue(const TargetMachine& target,
 }
 
 int
-MachineCodeForMethod::allocateOptionalArg(const TargetMachine& target,
-                                          const Type* type)
-{
-  const MachineFrameInfo& frameInfo = target.getFrameInfo();
-  
-  int size = INT_MAX;
-  if (frameInfo.argsOnStackHaveFixedSize())
-    size = frameInfo.getSizeOfEachArgOnStack(); 
-  else
-    {
-      size = target.findOptimalStorageSize(type);
-      assert(0 && "UNTESTED CODE: Size per stack argument is not fixed on this architecture: use actual argument sizes for computing optional arg offsets");
-    }
-  unsigned char align = target.DataLayout.getTypeAlignment(type);
-  
-  bool growUp;
-  int firstOffset = frameInfo.getFirstOptionalOutgoingArgOffset(*this, growUp);
-  
-  int offset = getCurrentOptionalArgsSize();
-  if (! growUp)
-    offset += size; 
-  
-  if (unsigned int mod = offset % align)
-    {
-      offset += align - mod;
-      size   += align - mod;
-    }
-  
-  offset = growUp? firstOffset + offset
-                 : firstOffset - offset;
-  
-  incrementCurrentOptionalArgsSize(size);
-  
-  return offset;
-}
-
-void
-MachineCodeForMethod::resetOptionalArgs(const TargetMachine& target)
-{
-  currentOptionalArgsSize = 0;
-}
-
-int
 MachineCodeForMethod::pushTempValue(const TargetMachine& target,
                                     unsigned int size)
 {