mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-25 00:29:20 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61715 91177308-0d34-0410-b5e6-96231b3b80d8
143 lines
5.4 KiB
C++
143 lines
5.4 KiB
C++
//===-- llvm/CodeGen/GCStrategy.h - Garbage collection ----------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// GCStrategy coordinates code generation algorithms and implements some itself
|
|
// in order to generate code compatible with a target code generator as
|
|
// specified in a function's 'gc' attribute. Algorithms are enabled by setting
|
|
// flags in a subclass's constructor, and some virtual methods can be
|
|
// overridden.
|
|
//
|
|
// When requested, the GCStrategy will be populated with data about each
|
|
// function which uses it. Specifically:
|
|
//
|
|
// - Safe points
|
|
// Garbage collection is generally only possible at certain points in code.
|
|
// GCStrategy can request that the collector insert such points:
|
|
//
|
|
// - At and after any call to a subroutine
|
|
// - Before returning from the current function
|
|
// - Before backwards branches (loops)
|
|
//
|
|
// - Roots
|
|
// When a reference to a GC-allocated object exists on the stack, it must be
|
|
// stored in an alloca registered with llvm.gcoot.
|
|
//
|
|
// This information can used to emit the metadata tables which are required by
|
|
// the target garbage collector runtime.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CODEGEN_GCSTRATEGY_H
|
|
#define LLVM_CODEGEN_GCSTRATEGY_H
|
|
|
|
#include "llvm/CodeGen/GCMetadata.h"
|
|
#include "llvm/Support/Registry.h"
|
|
#include <string>
|
|
|
|
namespace llvm {
|
|
|
|
class GCStrategy;
|
|
|
|
/// The GC strategy registry uses all the defaults from Registry.
|
|
///
|
|
typedef Registry<GCStrategy> GCRegistry;
|
|
|
|
/// GCStrategy describes a garbage collector algorithm's code generation
|
|
/// requirements, and provides overridable hooks for those needs which cannot
|
|
/// be abstractly described.
|
|
class GCStrategy {
|
|
public:
|
|
typedef std::vector<GCFunctionInfo*> list_type;
|
|
typedef list_type::iterator iterator;
|
|
|
|
private:
|
|
friend class GCModuleInfo;
|
|
const Module *M;
|
|
std::string Name;
|
|
|
|
list_type Functions;
|
|
|
|
protected:
|
|
unsigned NeededSafePoints; //< Bitmask of required safe points.
|
|
bool CustomReadBarriers; //< Default is to insert loads.
|
|
bool CustomWriteBarriers; //< Default is to insert stores.
|
|
bool CustomRoots; //< Default is to pass through to backend.
|
|
bool InitRoots; //< If set, roots are nulled during lowering.
|
|
bool UsesMetadata; //< If set, backend must emit metadata tables.
|
|
|
|
public:
|
|
GCStrategy();
|
|
|
|
virtual ~GCStrategy();
|
|
|
|
|
|
/// getName - The name of the GC strategy, for debugging.
|
|
///
|
|
const std::string &getName() const { return Name; }
|
|
|
|
/// getModule - The module within which the GC strategy is operating.
|
|
///
|
|
const Module &getModule() const { return *M; }
|
|
|
|
/// needsSafePoitns - True if safe points of any kind are required. By
|
|
// default, none are recorded.
|
|
bool needsSafePoints() const { return NeededSafePoints != 0; }
|
|
|
|
/// needsSafePoint(Kind) - True if the given kind of safe point is
|
|
// required. By default, none are recorded.
|
|
bool needsSafePoint(GC::PointKind Kind) const {
|
|
return (NeededSafePoints & 1 << Kind) != 0;
|
|
}
|
|
|
|
/// customWriteBarrier - By default, write barriers are replaced with simple
|
|
/// store instructions. If true, then
|
|
/// performCustomLowering must instead lower them.
|
|
bool customWriteBarrier() const { return CustomWriteBarriers; }
|
|
|
|
/// customReadBarrier - By default, read barriers are replaced with simple
|
|
/// load instructions. If true, then
|
|
/// performCustomLowering must instead lower them.
|
|
bool customReadBarrier() const { return CustomReadBarriers; }
|
|
|
|
/// customRoots - By default, roots are left for the code generator so it
|
|
/// can generate a stack map. If true, then
|
|
// performCustomLowering must delete them.
|
|
bool customRoots() const { return CustomRoots; }
|
|
|
|
/// initializeRoots - If set, gcroot intrinsics should initialize their
|
|
// allocas to null before the first use. This is
|
|
// necessary for most GCs and is enabled by default.
|
|
bool initializeRoots() const { return InitRoots; }
|
|
|
|
/// usesMetadata - If set, appropriate metadata tables must be emitted by
|
|
/// the back-end (assembler, JIT, or otherwise).
|
|
bool usesMetadata() const { return UsesMetadata; }
|
|
|
|
/// begin/end - Iterators for function metadata.
|
|
///
|
|
iterator begin() { return Functions.begin(); }
|
|
iterator end() { return Functions.end(); }
|
|
|
|
/// insertFunctionMetadata - Creates metadata for a function.
|
|
///
|
|
GCFunctionInfo *insertFunctionInfo(const Function &F);
|
|
|
|
/// initializeCustomLowering/performCustomLowering - If any of the actions
|
|
/// are set to custom, performCustomLowering must be overriden to transform
|
|
/// the corresponding actions to LLVM IR. initializeCustomLowering is
|
|
/// optional to override. These are the only GCStrategy methods through
|
|
/// which the LLVM IR can be modified.
|
|
virtual bool initializeCustomLowering(Module &F);
|
|
virtual bool performCustomLowering(Function &F);
|
|
};
|
|
|
|
}
|
|
|
|
#endif
|