Make more explicit and add some currently disabled error messages for

stack realignment on ARM.

Also check for function attributes as we do on X86 as well as
make explicit that we're checking can as well as needs in this function.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108582 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 4 deletions

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 182bd99371..3f0a2f1569 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -627,12 +627,26 @@ bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const {
 bool ARMBaseRegisterInfo::
 needsStackRealignment(const MachineFunction &MF) const {
   const MachineFrameInfo *MFI = MF.getFrameInfo();
+  const Function *F = MF.getFunction();
   const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
   unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
-  return (RealignStack &&
-          !AFI->isThumb1OnlyFunction() &&
-          (MFI->getMaxAlignment() > StackAlign) &&
-          !MFI->hasVarSizedObjects());
+  bool requiresRealignment =
+    RealignStack && ((MFI->getMaxAlignment() > StackAlign) ||
+                     F->hasFnAttr(Attribute::StackAlignment));
+    
+  // FIXME: Currently we don't support stack realignment for functions with
+  //        variable-sized allocas.
+  // FIXME: It's more complicated than this...
+  if (0 && requiresRealignment && MFI->hasVarSizedObjects())
+    report_fatal_error(
+      "Stack realignment in presense of dynamic allocas is not supported");
+  
+  // FIXME: This probably isn't the right place for this.
+  if (0 && requiresRealignment && AFI->isThumb1OnlyFunction())
+    report_fatal_error(
+      "Stack realignment in thumb1 functions is not supported");
+  
+  return requiresRealignment && canRealignStack(MF);
 }
 
 bool ARMBaseRegisterInfo::