SPARC v9 stack pointer bias.

64-bit SPARC v9 processes use biased stack and frame pointers, so the
current function's stack frame is located at %sp+BIAS .. %fp+BIAS where
BIAS = 2047.

This makes more local variables directly accessible via [%fp+simm13]
addressing.

llvm-svn: 178965

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Target/Sparc/SparcSubtarget.h b/llvm/lib/Target/Sparc/SparcSubtarget.h
index a81931b34aa..b94dd110ea9 100644
--- a/llvm/lib/Target/Sparc/SparcSubtarget.h
+++ b/llvm/lib/Target/Sparc/SparcSubtarget.h
@@ -52,6 +52,12 @@ public:
     }
     return std::string(p);
   }
+
+  /// The 64-bit ABI uses biased stack and frame pointers, so the stack frame
+  /// of the current function is the area from [%sp+BIAS] to [%fp+BIAS].
+  int64_t getStackPointerBias() const {
+    return is64Bit() ? 2047 : 0;
+  }
 };
 
 } // end namespace llvm