[WinEH] Make funclet return instrs pseudo instrs

This makes catchret look more like a branch, and less like a weird use
of BlockAddress. It also lets us get away from
llvm.x86.seh.restoreframe, which relies on the old parentfpoffset label
arithmetic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247936 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 35 insertions, 0 deletions

diff --git a/lib/Target/X86/X86ExpandPseudo.cpp b/lib/Target/X86/X86ExpandPseudo.cpp
index 6a5a28e546f2..c9441bd0c2f1 100644
--- a/lib/Target/X86/X86ExpandPseudo.cpp
+++ b/lib/Target/X86/X86ExpandPseudo.cpp
@@ -141,6 +141,41 @@ bool X86ExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
     // The EH_RETURN pseudo is really removed during the MC Lowering.
     return true;
   }
+
+  case X86::CLEANUPRET: {
+    // Replace CATCHRET with the appropriate RET.
+    unsigned RetOp = STI->is64Bit() ? X86::RETQ : X86::RETL;
+    BuildMI(MBB, MBBI, DL, TII->get(RetOp));
+    MBBI->eraseFromParent();
+    return true;
+  }
+
+  case X86::CATCHRET: {
+    MachineBasicBlock *TargetMBB = MBBI->getOperand(0).getMBB();
+
+    // Fill EAX/RAX with the address of the target block.
+    unsigned ReturnReg = STI->is64Bit() ? X86::RAX : X86::EAX;
+    unsigned RetOp = STI->is64Bit() ? X86::RETQ : X86::RETL;
+    if (STI->is64Bit()) {
+      // LEA64r TargetMBB(%rip), %rax
+      BuildMI(MBB, MBBI, DL, TII->get(X86::LEA64r), ReturnReg)
+          .addReg(X86::RIP)
+          .addImm(0)
+          .addReg(0)
+          .addMBB(TargetMBB)
+          .addReg(0);
+    } else {
+      // MOV32ri $TargetMBB, %eax
+      BuildMI(MBB, MBBI, DL, TII->get(X86::MOV32ri))
+          .addReg(ReturnReg)
+          .addMBB(TargetMBB);
+    }
+
+    // Replace CATCHRET with the appropriate RET.
+    BuildMI(MBB, MBBI, DL, TII->get(RetOp)).addReg(ReturnReg);
+    MBBI->eraseFromParent();
+    return true;
+  }
   }
   llvm_unreachable("Previous switch has a fallthrough?");
 }