Implement -disable-non-leaf-fp-elim which disable frame pointer elimination

optimization for non-leaf functions. This will be hooked up to gcc's
-momit-leaf-frame-pointer option. rdar://7886181


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101984 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp
index 871b148..d90755a 100644
--- a/lib/Target/TargetMachine.cpp
+++ b/lib/Target/TargetMachine.cpp
@@ -11,6 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
@@ -25,6 +27,7 @@ namespace llvm {
   bool LessPreciseFPMADOption;
   bool PrintMachineCode;
   bool NoFramePointerElim;
+  bool NoFramePointerElimNonLeaf;
   bool NoExcessFPPrecision;
   bool UnsafeFPMath;
   bool FiniteOnlyFPMathOption;
@@ -58,6 +61,11 @@ DisableFPElim("disable-fp-elim",
   cl::location(NoFramePointerElim),
   cl::init(false));
 static cl::opt<bool, true>
+DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
+  cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
+  cl::location(NoFramePointerElimNonLeaf),
+  cl::init(false));
+static cl::opt<bool, true>
 DisableExcessPrecision("disable-excess-fp-precision",
   cl::desc("Disable optimizations that may increase FP precision"),
   cl::location(NoExcessFPPrecision),
@@ -268,6 +276,18 @@ void TargetMachine::setDataSections(bool V) {
 }
 
 namespace llvm {
+  /// DisableFramePointerElim - This returns true if frame pointer elimination
+  /// optimization should be disabled for the given machine function.
+  bool DisableFramePointerElim(const MachineFunction &MF) {
+    if (NoFramePointerElim)
+      return true;
+    if (NoFramePointerElimNonLeaf) {
+      const MachineFrameInfo *MFI = MF.getFrameInfo();
+      return MFI->hasCalls();
+    }
+    return false;
+  }
+
   /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
   /// is specified on the command line.  When this flag is off(default), the
   /// code generator is not allowed to generate mad (multiply add) if the