[llvm-commits] [llvm] r82693 - /llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp

[Bob Wilson]

Author: bwilson
Date: Thu Sep 24 11:42:27 2009
New Revision: 82693

URL: http://llvm.org/viewvc/llvm-project?rev=82693&view=rev
Log:
Fix a hypothetical problem for targets with StackGrowsUp and a non-zero
LocalAreaOffset.  (We don't have any of those right now.)
PEI::calculateFrameObjectOffsets includes the absolute value of the
LocalAreaOffset in the cumulative offset value used to calculate the
stack frame size.  It then adds the raw value of the LocalAreaOffset
to the stack size.  For a StackGrowsDown target, that raw value is negative
and has the effect of cancelling out the absolute value that was added
earlier, but that obviously won't work for a StackGrowsUp target.  Change
to subtract the absolute value of the LocalAreaOffset.

Modified:
    llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp

Modified: llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp?rev=82693&r1=82692&r2=82693&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp (original)
+++ llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp Thu Sep 24 11:42:27 2009
@@ -471,11 +471,12 @@
   // 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 nonnegative.
-  int64_t Offset = TFI.getOffsetOfLocalArea();
+  int LocalAreaOffset = TFI.getOffsetOfLocalArea();
   if (StackGrowsDown)
-    Offset = -Offset;
-  assert(Offset >= 0
+    LocalAreaOffset = -LocalAreaOffset;
+  assert(LocalAreaOffset >= 0
          && "Local area offset should be in direction of stack growth");
+  int64_t Offset = LocalAreaOffset;
 
   // If there are fixed sized objects that are preallocated in the local area,
   // non-fixed objects can't be allocated right at the start of local area.
@@ -588,7 +589,7 @@
   }
 
   // Update frame info to pretend that this is part of the stack...
-  FFI->setStackSize(Offset+TFI.getOffsetOfLocalArea());
+  FFI->setStackSize(Offset - LocalAreaOffset);
 
   // Remember the required stack alignment in case targets need it to perform
   // dynamic stack alignment.