Unify alloca, outgoing arg, and prolog construction

src/IceTargetLoweringARM32.cpp

 //===- subzero/src/IceTargetLoweringARM32.cpp - ARM32 lowering ------------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 831 matching lines @@
   uint32_t SpillAreaPaddingBytes = 0;
   uint32_t LocalsSlotsPaddingBytes = 0;
   alignStackSpillAreas(PreservedRegsSizeBytes, SpillAreaAlignmentBytes,
                        GlobalsSize, LocalsSlotsAlignmentBytes,
                        &SpillAreaPaddingBytes, &LocalsSlotsPaddingBytes);
   SpillAreaSizeBytes += SpillAreaPaddingBytes + LocalsSlotsPaddingBytes;
   uint32_t GlobalsAndSubsequentPaddingSize =
       GlobalsSize + LocalsSlotsPaddingBytes;
 
   // Adds the out args space to the stack, and align SP if necessary.
-  if (!NeedsStackAlignment) {
-    SpillAreaSizeBytes += MaxOutArgsSizeBytes;
-  } else {
+  if (NeedsStackAlignment) {
     uint32_t StackOffset = PreservedRegsSizeBytes;
     uint32_t StackSize = applyStackAlignment(StackOffset + SpillAreaSizeBytes);
     StackSize = applyStackAlignment(StackSize + MaxOutArgsSizeBytes);
     SpillAreaSizeBytes = StackSize - StackOffset;
+  } else {
+    SpillAreaSizeBytes += MaxOutArgsSizeBytes;
   }
 
   // Combine fixed alloca with SpillAreaSize.
   SpillAreaSizeBytes += FixedAllocaSizeBytes;
 
   // Generate "sub sp, SpillAreaSizeBytes"
   if (SpillAreaSizeBytes) {
     // Use the scratch register if needed to legalize the immediate.
     Operand *SubAmount = legalize(Ctx->getConstantInt32(SpillAreaSizeBytes),
                                   Legal_Reg | Legal_Flex, getReservedTmpReg());
@@ skipping 4861 matching lines @@
   // Technically R9 is used for TLS with Sandboxing, and we reserve it.
   // However, for compatibility with current NaCl LLVM, don't claim that.
   Str << ".eabi_attribute 14, 3   @ Tag_ABI_PCS_R9_use: Not used\n";
 }
 
 llvm::SmallBitVector TargetARM32::TypeToRegisterSet[IceType_NUM];
 llvm::SmallBitVector TargetARM32::RegisterAliases[RegARM32::Reg_NUM];
 llvm::SmallBitVector TargetARM32::ScratchRegs;
 
 } // end of namespace Ice