[llvm] r239568 - [Stackmaps][X86] Remove EFLAGS and IP registers from the live-out mask.

[Juergen Ributzka]

Author: ributzka
Date: Thu Jun 11 17:40:04 2015
New Revision: 239568

URL: http://llvm.org/viewvc/llvm-project?rev=239568&view=rev
Log:
[Stackmaps][X86] Remove EFLAGS and IP registers from the live-out mask.

Remove the EFLAGS from the stackmap live-out mask. The EFLAGS register is not
supposed to be part of that set, because the X86 calling conventions mark the
register as NOT preserved.

Also remove the IP registers, since spilling and restoring those doesn't really
make any sense.

Related to rdar://problem/21019635.

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

Modified: llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp?rev=239568&r1=239567&r2=239568&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp Thu Jun 11 17:40:04 2015
@@ -419,6 +419,22 @@ BitVector X86RegisterInfo::getReservedRe
   return Reserved;
 }
 
+void X86RegisterInfo::adjustStackMapLiveOutMask(uint32_t *Mask) const {
+  // Check if the EFLAGS register is marked as live-out. This shouldn't happen,
+  // because the calling convention defines the EFLAGS register as NOT
+  // preserved.
+  //
+  // Unfortunatelly the EFLAGS show up as live-out after branch folding. Adding
+  // an assert to track this and clear the register afterwards to avoid
+  // unnecessary crashes during release builds.
+  assert(!(Mask[X86::EFLAGS / 32] & (1U << (X86::EFLAGS % 32))) &&
+         "EFLAGS are not live-out from a patchpoint.");
+
+  // Also clean other registers that don't need preserving (IP).
+  for (auto Reg : {X86::EFLAGS, X86::RIP, X86::EIP, X86::IP})
+    Mask[Reg / 32] &= ~(1U << (Reg % 32));
+}
+
 //===----------------------------------------------------------------------===//
 // Stack Frame Processing methods
 //===----------------------------------------------------------------------===//

Modified: llvm/trunk/lib/Target/X86/X86RegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86RegisterInfo.h?rev=239568&r1=239567&r2=239568&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86RegisterInfo.h (original)
+++ llvm/trunk/lib/Target/X86/X86RegisterInfo.h Thu Jun 11 17:40:04 2015
@@ -104,6 +104,8 @@ public:
   /// register scavenger to determine what registers are free.
   BitVector getReservedRegs(const MachineFunction &MF) const override;
 
+  void adjustStackMapLiveOutMask(uint32_t *Mask) const override;
+
   bool hasBasePointer(const MachineFunction &MF) const;
 
   bool canRealignStack(const MachineFunction &MF) const;