llvm-6502/include/llvm/IR/Statepoint.h

299 lines
9.6 KiB
C++

//===-- llvm/IR/Statepoint.h - gc.statepoint utilities ------ --*- 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 utility functions and a wrapper class analogous to
// CallSite for accessing the fields of gc.statepoint, gc.relocate, and
// gc.result intrinsics
//
//===----------------------------------------------------------------------===//
#ifndef __LLVM_IR_STATEPOINT_H
#define __LLVM_IR_STATEPOINT_H
#include "llvm/ADT/iterator_range.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/Support/Compiler.h"
namespace llvm {
class GCRelocateOperands;
class ImmutableStatepoint;
bool isStatepoint(const ImmutableCallSite &CS);
bool isStatepoint(const Value *inst);
bool isStatepoint(const Value &inst);
bool isGCRelocate(const Value *inst);
bool isGCRelocate(const ImmutableCallSite &CS);
bool isGCResult(const Value *inst);
bool isGCResult(const ImmutableCallSite &CS);
/// Analogous to CallSiteBase, this provides most of the actual
/// functionality for Statepoint and ImmutableStatepoint. It is
/// templatized to allow easily specializing of const and non-const
/// concrete subtypes. This is structured analogous to CallSite
/// rather than the IntrinsicInst.h helpers since we want to support
/// invokable statepoints in the near future.
/// TODO: This does not currently allow the if(Statepoint S = ...)
/// idiom used with CallSites. Consider refactoring to support.
template <typename InstructionTy, typename ValueTy, typename CallSiteTy>
class StatepointBase {
CallSiteTy StatepointCS;
void *operator new(size_t, unsigned) = delete;
void *operator new(size_t s) = delete;
protected:
explicit StatepointBase(InstructionTy *I) : StatepointCS(I) {
assert(isStatepoint(I));
}
explicit StatepointBase(CallSiteTy CS) : StatepointCS(CS) {
assert(isStatepoint(CS));
}
public:
typedef typename CallSiteTy::arg_iterator arg_iterator;
/// Return the underlying CallSite.
CallSiteTy getCallSite() {
return StatepointCS;
}
/// Return the value actually being called or invoked.
ValueTy *actualCallee() {
return StatepointCS.getArgument(0);
}
/// Number of arguments to be passed to the actual callee.
int numCallArgs() {
return cast<ConstantInt>(StatepointCS.getArgument(1))->getZExtValue();
}
/// Number of additional arguments excluding those intended
/// for garbage collection.
int numTotalVMSArgs() {
return cast<ConstantInt>(StatepointCS.getArgument(3 + numCallArgs()))->getZExtValue();
}
typename CallSiteTy::arg_iterator call_args_begin() {
// 3 = callTarget, #callArgs, flag
int Offset = 3;
assert(Offset <= (int)StatepointCS.arg_size());
return StatepointCS.arg_begin() + Offset;
}
typename CallSiteTy::arg_iterator call_args_end() {
int Offset = 3 + numCallArgs();
assert(Offset <= (int)StatepointCS.arg_size());
return StatepointCS.arg_begin() + Offset;
}
/// range adapter for call arguments
iterator_range<arg_iterator> call_args() {
return iterator_range<arg_iterator>(call_args_begin(), call_args_end());
}
typename CallSiteTy::arg_iterator vm_state_begin() {
return call_args_end();
}
typename CallSiteTy::arg_iterator vm_state_end() {
int Offset = 3 + numCallArgs() + 1 + numTotalVMSArgs();
assert(Offset <= (int)StatepointCS.arg_size());
return StatepointCS.arg_begin() + Offset;
}
/// range adapter for vm state arguments
iterator_range<arg_iterator> vm_state_args() {
return iterator_range<arg_iterator>(vm_state_begin(), vm_state_end());
}
typename CallSiteTy::arg_iterator first_vm_state_stack_begin() {
// 6 = numTotalVMSArgs, 1st_objectID, 1st_bci,
// 1st_#stack, 1st_#local, 1st_#monitor
return vm_state_begin() + 6;
}
typename CallSiteTy::arg_iterator gc_args_begin() {
return vm_state_end();
}
typename CallSiteTy::arg_iterator gc_args_end() {
return StatepointCS.arg_end();
}
/// range adapter for gc arguments
iterator_range<arg_iterator> gc_args() {
return iterator_range<arg_iterator>(gc_args_begin(), gc_args_end());
}
/// Get list of all gc reloactes linked to this statepoint
/// May contain several relocations for the same base/derived pair.
/// For example this could happen due to relocations on unwinding
/// path of invoke.
std::vector<GCRelocateOperands> getRelocates(ImmutableStatepoint &IS);
#ifndef NDEBUG
/// Asserts if this statepoint is malformed. Common cases for failure
/// include incorrect length prefixes for variable length sections or
/// illegal values for parameters.
void verify() {
assert(numCallArgs() >= 0 &&
"number of arguments to actually callee can't be negative");
// The internal asserts in the iterator accessors do the rest.
(void)call_args_begin();
(void)call_args_end();
(void)vm_state_begin();
(void)vm_state_end();
(void)gc_args_begin();
(void)gc_args_end();
}
#endif
};
/// A specialization of it's base class for read only access
/// to a gc.statepoint.
class ImmutableStatepoint
: public StatepointBase<const Instruction, const Value,
ImmutableCallSite> {
typedef StatepointBase<const Instruction, const Value, ImmutableCallSite>
Base;
public:
explicit ImmutableStatepoint(const Instruction *I) : Base(I) {}
explicit ImmutableStatepoint(ImmutableCallSite CS) : Base(CS) {}
};
/// A specialization of it's base class for read-write access
/// to a gc.statepoint.
class Statepoint : public StatepointBase<Instruction, Value, CallSite> {
typedef StatepointBase<Instruction, Value, CallSite> Base;
public:
explicit Statepoint(Instruction *I) : Base(I) {}
explicit Statepoint(CallSite CS) : Base(CS) {}
};
/// Wraps a call to a gc.relocate and provides access to it's operands.
/// TODO: This should likely be refactored to resememble the wrappers in
/// InstrinsicInst.h.
class GCRelocateOperands {
ImmutableCallSite RelocateCS;
public:
GCRelocateOperands(const User* U) : RelocateCS(U) {
assert(isGCRelocate(U));
}
GCRelocateOperands(const Instruction *inst) : RelocateCS(inst) {
assert(isGCRelocate(inst));
}
GCRelocateOperands(CallSite CS) : RelocateCS(CS) {
assert(isGCRelocate(CS));
}
/// Return true if this relocate is tied to the invoke statepoint.
/// This includes relocates which are on the unwinding path.
bool isTiedToInvoke() const {
const Value *Token = RelocateCS.getArgument(0);
return isa<ExtractValueInst>(Token) ||
isa<InvokeInst>(Token);
}
/// Get enclosed relocate intrinsic
ImmutableCallSite getUnderlyingCallSite() {
return RelocateCS;
}
/// The statepoint with which this gc.relocate is associated.
const Instruction *statepoint() {
const Value *token = RelocateCS.getArgument(0);
// This takes care both of relocates for call statepoints and relocates
// on normal path of invoke statepoint.
if (!isa<ExtractValueInst>(token)) {
return cast<Instruction>(token);
}
// This relocate is on exceptional path of an invoke statepoint
const BasicBlock *invokeBB =
cast<Instruction>(token)->getParent()->getUniquePredecessor();
assert(invokeBB && "safepoints should have unique landingpads");
assert(invokeBB->getTerminator() && "safepoint block should be well formed");
assert(isStatepoint(invokeBB->getTerminator()));
return invokeBB->getTerminator();
}
/// The index into the associate statepoint's argument list
/// which contains the base pointer of the pointer whose
/// relocation this gc.relocate describes.
unsigned basePtrIndex() {
return cast<ConstantInt>(RelocateCS.getArgument(1))->getZExtValue();
}
/// The index into the associate statepoint's argument list which
/// contains the pointer whose relocation this gc.relocate describes.
unsigned derivedPtrIndex() {
return cast<ConstantInt>(RelocateCS.getArgument(2))->getZExtValue();
}
Value *basePtr() {
ImmutableCallSite CS(statepoint());
return *(CS.arg_begin() + basePtrIndex());
}
Value *derivedPtr() {
ImmutableCallSite CS(statepoint());
return *(CS.arg_begin() + derivedPtrIndex());
}
};
template <typename InstructionTy, typename ValueTy, typename CallSiteTy>
std::vector<GCRelocateOperands>
StatepointBase<InstructionTy, ValueTy, CallSiteTy>::
getRelocates(ImmutableStatepoint &IS) {
std::vector<GCRelocateOperands> res;
ImmutableCallSite StatepointCS = IS.getCallSite();
// Search for relocated pointers. Note that working backwards from the
// gc_relocates ensures that we only get pairs which are actually relocated
// and used after the statepoint.
for (const User *U : StatepointCS.getInstruction()->users()) {
if (isGCRelocate(U)) {
res.push_back(GCRelocateOperands(U));
}
}
if (!StatepointCS.isInvoke()) {
return res;
}
// We need to scan thorough exceptional relocations if it is invoke statepoint
LandingPadInst *LandingPad =
cast<InvokeInst>(StatepointCS.getInstruction())->getLandingPadInst();
// Search for extract value from landingpad instruction to which
// gc relocates will be attached
for (const User *LandingPadUser : LandingPad->users()) {
if (!isa<ExtractValueInst>(LandingPadUser)) {
continue;
}
// gc relocates should be attached to this extract value
for (const User *U : LandingPadUser->users()) {
if (isGCRelocate(U)) {
res.push_back(GCRelocateOperands(U));
}
}
}
return res;
}
}
#endif