llvm-6502/lib/CodeGen/AsmPrinter/Win64Exception.h
Reid Kleckner 504fa89c8e CodeGen support for x86_64 SEH catch handlers in LLVM
This adds handling for ExceptionHandling::MSVC, used by the
x86_64-pc-windows-msvc triple. It assumes that filter functions have
already been outlined in either the frontend or the backend. Filter
functions are used in place of the landingpad catch clause type info
operands. In catch clause order, the first filter to return true will
catch the exception.

The C specific handler table expects the landing pad to be split into
one block per handler, but LLVM IR uses a single landing pad for all
possible unwind actions. This patch papers over the mismatch by
synthesizing single instruction BBs for every catch clause to fill in
the EH selector that the landing pad block expects.

Missing functionality:
- Accessing data in the parent frame from outlined filters
- Cleanups (from __finally) are unsupported, as they will require
  outlining and parent frame access
- Filter clauses are unsupported, as there's no clear analogue in SEH

In other words, this is the minimal set of changes needed to write IR to
catch arbitrary exceptions and resume normal execution.

Reviewers: majnemer

Differential Revision: http://reviews.llvm.org/D6300

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225904 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-14 01:05:27 +00:00

57 lines
1.7 KiB
C++

//===-- Win64Exception.h - Windows Exception Handling ----------*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing windows exception info into asm files.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
#include "EHStreamer.h"
namespace llvm {
class MachineFunction;
class Win64Exception : public EHStreamer {
/// Per-function flag to indicate if personality info should be emitted.
bool shouldEmitPersonality;
/// Per-function flag to indicate if the LSDA should be emitted.
bool shouldEmitLSDA;
/// Per-function flag to indicate if frame moves info should be emitted.
bool shouldEmitMoves;
void emitCSpecificHandlerTable();
const MCSymbolRefExpr *createImageRel32(const MCSymbol *Value);
public:
//===--------------------------------------------------------------------===//
// Main entry points.
//
Win64Exception(AsmPrinter *A);
virtual ~Win64Exception();
/// Emit all exception information that should come after the content.
void endModule() override;
/// Gather pre-function exception information. Assumes being emitted
/// immediately after the function entry point.
void beginFunction(const MachineFunction *MF) override;
/// Gather and emit post-function exception information.
void endFunction(const MachineFunction *) override;
};
}
#endif