[WinEH] Emit prologues and epilogues for funclets

Summary:
32-bit funclets have short prologues that allocate enough stack for the
largest call in the whole function. The runtime saves CSRs for the
funclet. It doesn't restore CSRs after we finally transfer control back
to the parent funciton via a CATCHRET, but that's a separate issue.
32-bit funclets also have to adjust the incoming EBP value, which is
what llvm.x86.seh.recoverframe does in the old model.

64-bit funclets need to spill CSRs as normal. For simplicity, this just
spills the same set of CSRs as the parent function, rather than trying
to compute different CSR sets for the parent function and each funclet.
64-bit funclets also allocate enough stack space for the largest
outgoing call frame, like 32-bit.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12546

llvm-svn: 247092

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86FrameLowering.h b/llvm/lib/Target/X86/X86FrameLowering.h
index dd83928b46c..7cbd18bd4d0 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.h
+++ b/llvm/lib/Target/X86/X86FrameLowering.h
@@ -154,6 +154,13 @@ private:
                                            MachineBasicBlock::iterator MBBI,
                                            DebugLoc DL, int64_t Offset,
                                            bool InEpilogue) const;
+
+  /// Sets up EBP and optionally ESI based on the incoming EBP value.  Only
+  /// needed for 32-bit. Used in funclet prologues and at catchret destinations.
+  MachineBasicBlock::iterator
+  restoreWin32EHFrameAndBasePtr(MachineBasicBlock &MBB,
+                                MachineBasicBlock::iterator MBBI,
+                                DebugLoc DL) const;
 };
 
 } // End llvm namespace