llvm-6502/include/llvm/Target/TargetOpcodes.h
Sanjoy Das 1991e2a4df [CodeGen] Introduce a FAULTING_LOAD_OP pseudo-op.
Summary:
This instruction encodes a loading operation that may fault, and a label
to branch to if the load page-faults.  The locations of potentially
faulting loads and their "handler" destinations are recorded in a
FaultMap section, meant to be consumed by LLVM's clients.

Nothing generates FAULTING_LOAD_OP instructions yet, but they will be
used in a future change.

The documentation (FaultMaps.rst) needs improvement and I will update
this diff with a more expanded version shortly.

Depends on D10196

Reviewers: rnk, reames, AndyAyers, ab, atrick, pgavlin

Reviewed By: atrick, pgavlin

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10197

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239740 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 18:44:08 +00:00

136 lines
5.7 KiB
C++

//===-- llvm/Target/TargetOpcodes.h - Target Indep Opcodes ------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the target independent instruction opcodes.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETOPCODES_H
#define LLVM_TARGET_TARGETOPCODES_H
namespace llvm {
/// Invariant opcodes: All instruction sets have these as their low opcodes.
///
/// Every instruction defined here must also appear in Target.td and the order
/// must be the same as in CodeGenTarget.cpp.
///
namespace TargetOpcode {
enum {
PHI = 0,
INLINEASM = 1,
CFI_INSTRUCTION = 2,
EH_LABEL = 3,
GC_LABEL = 4,
/// KILL - This instruction is a noop that is used only to adjust the
/// liveness of registers. This can be useful when dealing with
/// sub-registers.
KILL = 5,
/// EXTRACT_SUBREG - This instruction takes two operands: a register
/// that has subregisters, and a subregister index. It returns the
/// extracted subregister value. This is commonly used to implement
/// truncation operations on target architectures which support it.
EXTRACT_SUBREG = 6,
/// INSERT_SUBREG - This instruction takes three operands: a register that
/// has subregisters, a register providing an insert value, and a
/// subregister index. It returns the value of the first register with the
/// value of the second register inserted. The first register is often
/// defined by an IMPLICIT_DEF, because it is commonly used to implement
/// anyext operations on target architectures which support it.
INSERT_SUBREG = 7,
/// IMPLICIT_DEF - This is the MachineInstr-level equivalent of undef.
IMPLICIT_DEF = 8,
/// SUBREG_TO_REG - This instruction is similar to INSERT_SUBREG except that
/// the first operand is an immediate integer constant. This constant is
/// often zero, because it is commonly used to assert that the instruction
/// defining the register implicitly clears the high bits.
SUBREG_TO_REG = 9,
/// COPY_TO_REGCLASS - This instruction is a placeholder for a plain
/// register-to-register copy into a specific register class. This is only
/// used between instruction selection and MachineInstr creation, before
/// virtual registers have been created for all the instructions, and it's
/// only needed in cases where the register classes implied by the
/// instructions are insufficient. It is emitted as a COPY MachineInstr.
COPY_TO_REGCLASS = 10,
/// DBG_VALUE - a mapping of the llvm.dbg.value intrinsic
DBG_VALUE = 11,
/// REG_SEQUENCE - This variadic instruction is used to form a register that
/// represents a consecutive sequence of sub-registers. It's used as a
/// register coalescing / allocation aid and must be eliminated before code
/// emission.
// In SDNode form, the first operand encodes the register class created by
// the REG_SEQUENCE, while each subsequent pair names a vreg + subreg index
// pair. Once it has been lowered to a MachineInstr, the regclass operand
// is no longer present.
/// e.g. v1027 = REG_SEQUENCE v1024, 3, v1025, 4, v1026, 5
/// After register coalescing references of v1024 should be replace with
/// v1027:3, v1025 with v1027:4, etc.
REG_SEQUENCE = 12,
/// COPY - Target-independent register copy. This instruction can also be
/// used to copy between subregisters of virtual registers.
COPY = 13,
/// BUNDLE - This instruction represents an instruction bundle. Instructions
/// which immediately follow a BUNDLE instruction which are marked with
/// 'InsideBundle' flag are inside the bundle.
BUNDLE = 14,
/// Lifetime markers.
LIFETIME_START = 15,
LIFETIME_END = 16,
/// A Stackmap instruction captures the location of live variables at its
/// position in the instruction stream. It is followed by a shadow of bytes
/// that must lie within the function and not contain another stackmap.
STACKMAP = 17,
/// Patchable call instruction - this instruction represents a call to a
/// constant address, followed by a series of NOPs. It is intended to
/// support optimizations for dynamic languages (such as javascript) that
/// rewrite calls to runtimes with more efficient code sequences.
/// This also implies a stack map.
PATCHPOINT = 18,
/// This pseudo-instruction loads the stack guard value. Targets which need
/// to prevent the stack guard value or address from being spilled to the
/// stack should override TargetLowering::emitLoadStackGuardNode and
/// additionally expand this pseudo after register allocation.
LOAD_STACK_GUARD = 19,
/// Call instruction with associated vm state for deoptimization and list
/// of live pointers for relocation by the garbage collector. It is
/// intended to support garbage collection with fully precise relocating
/// collectors and deoptimizations in either the callee or caller.
STATEPOINT = 20,
/// Instruction that records the offset of a function's frame allocation in a
/// label. Created by the llvm.frameallocate intrinsic. It has two arguments:
/// the symbol for the label and the frame index of the stack allocation.
FRAME_ALLOC = 21,
/// Loading instruction that may page fault, bundled with associated
/// information on how to handle such a page fault. It is intended to support
/// "zero cost" null checks in managed languages by allowing LLVM to fold
/// comparisions into existing memory operations.
FAULTING_LOAD_OP = 22,
};
} // end namespace TargetOpcode
} // end namespace llvm
#endif