It's not necessary to do rounding for alloca operations when the requested

alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 93 insertions, 0 deletions

diff --git a/lib/Target/PowerPC/PPCFrameInfo.h b/lib/Target/PowerPC/PPCFrameInfo.h
new file mode 100644
index 0000000..81365e9
--- /dev/null
+++ b/lib/Target/PowerPC/PPCFrameInfo.h
@@ -0,0 +1,93 @@
+//===-- PPCFrameInfo.h - Define TargetFrameInfo for PowerPC -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef POWERPC_FRAMEINFO_H
+#define POWERPC_FRAMEINFO_H
+
+#include "PPC.h"
+#include "llvm/Target/TargetFrameInfo.h"
+#include "llvm/Target/TargetMachine.h"
+
+namespace llvm {
+
+class PPCFrameInfo: public TargetFrameInfo {
+  const TargetMachine &TM;
+
+public:
+  PPCFrameInfo(const TargetMachine &tm, bool LP64)
+    : TargetFrameInfo(TargetFrameInfo::StackGrowsDown, 16, 0), TM(tm) {
+  }
+
+  /// getReturnSaveOffset - Return the previous frame offset to save the
+  /// return address.
+  static unsigned getReturnSaveOffset(bool LP64, bool isMacho) {
+    if (isMacho)
+      return LP64 ? 16 : 8;
+    // For ELF 32 ABI:
+    return 4;
+  }
+
+  /// getFramePointerSaveOffset - Return the previous frame offset to save the
+  /// frame pointer.
+  static unsigned getFramePointerSaveOffset(bool LP64, bool isMacho) {
+    // For MachO ABI:
+    // Use the TOC save slot in the PowerPC linkage area for saving the frame
+    // pointer (if needed.)  LLVM does not generate code that uses the TOC (R2
+    // is treated as a caller saved register.)
+    if (isMacho)
+      return LP64 ? 40 : 20;
+    
+    // For ELF 32 ABI:
+    // Save it right before the link register
+    return -4U;
+  }
+  
+  /// getLinkageSize - Return the size of the PowerPC ABI linkage area.
+  ///
+  static unsigned getLinkageSize(bool LP64, bool isMacho) {
+    if (isMacho)
+      return 6 * (LP64 ? 8 : 4);
+    
+    // For ELF 32 ABI:
+    return 8;
+  }
+
+  /// getMinCallArgumentsSize - Return the size of the minium PowerPC ABI
+  /// argument area.
+  static unsigned getMinCallArgumentsSize(bool LP64, bool isMacho) {
+    // For Macho ABI:
+    // The prolog code of the callee may store up to 8 GPR argument registers to
+    // the stack, allowing va_start to index over them in memory if its varargs.
+    // Because we cannot tell if this is needed on the caller side, we have to
+    // conservatively assume that it is needed.  As such, make sure we have at
+    // least enough stack space for the caller to store the 8 GPRs.
+    if (isMacho)
+      return 8 * (LP64 ? 8 : 4);
+    
+    // For ELF 32 ABI:
+    // There is no default stack allocated for the 8 first GPR arguments.
+    return 0;
+  }
+
+  /// getMinCallFrameSize - Return the minimum size a call frame can be using
+  /// the PowerPC ABI.
+  static unsigned getMinCallFrameSize(bool LP64, bool isMacho) {
+    // The call frame needs to be at least big enough for linkage and 8 args.
+    return getLinkageSize(LP64, isMacho) +
+           getMinCallArgumentsSize(LP64, isMacho);
+  }
+  
+};
+
+} // End llvm namespace
+
+#endif