[llvm-commits] [llvm] r63056 - in /llvm/trunk: include/llvm/Target/TargetOptions.h lib/Target/TargetMachine.cpp lib/Target/X86/X86RegisterInfo.cpp

[Dan Gohman]

Author: djg
Date: Mon Jan 26 16:22:31 2009
New Revision: 63056

URL: http://llvm.org/viewvc/llvm-project?rev=63056&view=rev
Log:
Implement Red Zone utilization on x86-64. This is currently
disabled by default; I'll enable it when I hook it up with
the llvm-gcc flag which controls it.

Modified:
    llvm/trunk/include/llvm/Target/TargetOptions.h
    llvm/trunk/lib/Target/TargetMachine.cpp
    llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp

Modified: llvm/trunk/include/llvm/Target/TargetOptions.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetOptions.h?rev=63056&r1=63055&r2=63056&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Target/TargetOptions.h (original)
+++ llvm/trunk/include/llvm/Target/TargetOptions.h Mon Jan 26 16:22:31 2009
@@ -107,6 +107,10 @@
   /// wth earlier copy coalescing.
   extern bool StrongPHIElim;
 
+  /// DisableRedZone - This flag disables use of the "Red Zone" on
+  /// targets which would otherwise have one.
+  extern bool DisableRedZone;
+
 } // End llvm namespace
 
 #endif

Modified: llvm/trunk/lib/Target/TargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetMachine.cpp?rev=63056&r1=63055&r2=63056&view=diff

==============================================================================
--- llvm/trunk/lib/Target/TargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/TargetMachine.cpp Mon Jan 26 16:22:31 2009
@@ -40,6 +40,7 @@
   bool VerboseAsm;
   bool DisableJumpTables;
   bool StrongPHIElim;
+  bool DisableRedZone;
 }
 
 static cl::opt<bool, true> PrintCode("print-machineinstrs",
@@ -164,6 +165,12 @@
            cl::location(StrongPHIElim),
            cl::init(false));
 
+static cl::opt<bool, true>
+DisableRedZoneOption("disable-red-zone",
+           cl::desc("Do not emit code that uses the red zone."),
+           cl::location(DisableRedZone),
+           cl::init(true));
+
 //---------------------------------------------------------------------------
 // TargetMachine Class
 //

Modified: llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp?rev=63056&r1=63055&r2=63056&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp Mon Jan 26 16:22:31 2009
@@ -721,6 +721,18 @@
   // Get desired stack alignment
   uint64_t MaxAlign  = MFI->getMaxAlignment();
 
+  // If this is x86-64 and the Red Zone is not disabled, if we are a leaf
+  // function, and use up to 128 bytes of stack space, don't have a frame
+  // pointer, calls, or dynamic alloca then we do not need to adjust the
+  // stack pointer (we fit in the Red Zone).
+  if (Is64Bit && !DisableRedZone &&
+      !MFI->hasVarSizedObjects() &&                // No dynamic alloca.
+      !MFI->hasCalls()) {                          // No calls.
+    StackSize = std::max((uint64_t)X86FI->getCalleeSavedFrameSize(),
+                         StackSize > 128 ? StackSize - 128 : 0);
+    MFI->setStackSize(StackSize);
+  }
+
   // Add RETADDR move area to callee saved frame size.
   int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
   if (TailCallReturnAddrDelta < 0)