[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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239568 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index e9b6bfc3273cd01d9bded3b07e377dffa84eb6e1..72703a848f8f43bdf0d02c309e752c9deda31f5d 100644 (file)
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -419,6 +419,22 @@ BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   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
 //===----------------------------------------------------------------------===//

diff --git a/lib/Target/X86/X86RegisterInfo.h b/lib/Target/X86/X86RegisterInfo.h
index a714c2a33d06f1c5cc3b7b965559856b290795e0..b754cadd0eb8926897401089b656fcf43cda3530 100644 (file)
--- a/lib/Target/X86/X86RegisterInfo.h
+++ b/lib/Target/X86/X86RegisterInfo.h
@@ -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;