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llvm-mirror/tools/llvm-jitlink/llvm-jitlink.h

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Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
//===---- llvm-jitlink.h - Session and format-specific decls ----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
2020-08-11 03:48:30 +02:00
// llvm-jitlink Session class and tool utilities.
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_JITLINK_LLVM_JITLINK_H
#define LLVM_TOOLS_LLVM_JITLINK_LLVM_JITLINK_H
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringSet.h"
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
#include "llvm/ADT/Triple.h"
#include "llvm/ExecutionEngine/Orc/Core.h"
#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
#include "llvm/ExecutionEngine/Orc/OrcRPCTargetProcessControl.h"
#include "llvm/ExecutionEngine/Orc/Shared/FDRawByteChannel.h"
#include "llvm/ExecutionEngine/Orc/Shared/RPCUtils.h"
#include "llvm/ExecutionEngine/Orc/TargetProcessControl.h"
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
#include "llvm/ExecutionEngine/RuntimeDyldChecker.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Regex.h"
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
#include "llvm/Support/raw_ostream.h"
#include <vector>
namespace llvm {
struct Session;
/// ObjectLinkingLayer with additional support for symbol promotion.
class LLVMJITLinkObjectLinkingLayer : public orc::ObjectLinkingLayer {
public:
[ORC] Add support for resource tracking/removal (removable code). This patch introduces new APIs to support resource tracking and removal in Orc. It is intended as a thread-safe generalization of the removeModule concept from OrcV1. Clients can now create ResourceTracker objects (using JITDylib::createResourceTracker) to track resources for each MaterializationUnit (code, data, aliases, absolute symbols, etc.) added to the JIT. Every MaterializationUnit will be associated with a ResourceTracker, and ResourceTrackers can be re-used for multiple MaterializationUnits. Each JITDylib has a default ResourceTracker that will be used for MaterializationUnits added to that JITDylib if no ResourceTracker is explicitly specified. Two operations can be performed on ResourceTrackers: transferTo and remove. The transferTo operation transfers tracking of the resources to a different ResourceTracker object, allowing ResourceTrackers to be merged to reduce administrative overhead (the source tracker is invalidated in the process). The remove operation removes all resources associated with a ResourceTracker, including any symbols defined by MaterializationUnits associated with the tracker, and also invalidates the tracker. These operations are thread safe, and should work regardless of the the state of the MaterializationUnits. In the case of resource transfer any existing resources associated with the source tracker will be transferred to the destination tracker, and all future resources for those units will be automatically associated with the destination tracker. In the case of resource removal all already-allocated resources will be deallocated, any if any program representations associated with the tracker have not been compiled yet they will be destroyed. If any program representations are currently being compiled then they will be prevented from completing: their MaterializationResponsibility will return errors on any attempt to update the JIT state. Clients (usually Layer writers) wishing to track resources can implement the ResourceManager API to receive notifications when ResourceTrackers are transferred or removed. The MaterializationResponsibility::withResourceKeyDo method can be used to create associations between the key for a ResourceTracker and an allocated resource in a thread-safe way. RTDyldObjectLinkingLayer and ObjectLinkingLayer are updated to use the ResourceManager API to enable tracking and removal of memory allocated by the JIT linker. The new JITDylib::clear method can be used to trigger removal of every ResourceTracker associated with the JITDylib (note that this will only remove resources for the JITDylib, it does not run static destructors). This patch includes unit tests showing basic usage. A follow-up patch will update the Kaleidoscope and BuildingAJIT tutorial series to OrcV2 and will use this API to release code associated with anonymous expressions.
2020-09-11 18:50:41 +02:00
using orc::ObjectLinkingLayer::add;
LLVMJITLinkObjectLinkingLayer(Session &S,
jitlink::JITLinkMemoryManager &MemMgr);
[ORC] Add support for resource tracking/removal (removable code). This patch introduces new APIs to support resource tracking and removal in Orc. It is intended as a thread-safe generalization of the removeModule concept from OrcV1. Clients can now create ResourceTracker objects (using JITDylib::createResourceTracker) to track resources for each MaterializationUnit (code, data, aliases, absolute symbols, etc.) added to the JIT. Every MaterializationUnit will be associated with a ResourceTracker, and ResourceTrackers can be re-used for multiple MaterializationUnits. Each JITDylib has a default ResourceTracker that will be used for MaterializationUnits added to that JITDylib if no ResourceTracker is explicitly specified. Two operations can be performed on ResourceTrackers: transferTo and remove. The transferTo operation transfers tracking of the resources to a different ResourceTracker object, allowing ResourceTrackers to be merged to reduce administrative overhead (the source tracker is invalidated in the process). The remove operation removes all resources associated with a ResourceTracker, including any symbols defined by MaterializationUnits associated with the tracker, and also invalidates the tracker. These operations are thread safe, and should work regardless of the the state of the MaterializationUnits. In the case of resource transfer any existing resources associated with the source tracker will be transferred to the destination tracker, and all future resources for those units will be automatically associated with the destination tracker. In the case of resource removal all already-allocated resources will be deallocated, any if any program representations associated with the tracker have not been compiled yet they will be destroyed. If any program representations are currently being compiled then they will be prevented from completing: their MaterializationResponsibility will return errors on any attempt to update the JIT state. Clients (usually Layer writers) wishing to track resources can implement the ResourceManager API to receive notifications when ResourceTrackers are transferred or removed. The MaterializationResponsibility::withResourceKeyDo method can be used to create associations between the key for a ResourceTracker and an allocated resource in a thread-safe way. RTDyldObjectLinkingLayer and ObjectLinkingLayer are updated to use the ResourceManager API to enable tracking and removal of memory allocated by the JIT linker. The new JITDylib::clear method can be used to trigger removal of every ResourceTracker associated with the JITDylib (note that this will only remove resources for the JITDylib, it does not run static destructors). This patch includes unit tests showing basic usage. A follow-up patch will update the Kaleidoscope and BuildingAJIT tutorial series to OrcV2 and will use this API to release code associated with anonymous expressions.
2020-09-11 18:50:41 +02:00
Error add(orc::ResourceTrackerSP RT,
std::unique_ptr<MemoryBuffer> O) override;
private:
Session &S;
};
using LLVMJITLinkChannel = orc::shared::FDRawByteChannel;
using LLVMJITLinkRPCEndpoint =
orc::shared::MultiThreadedRPCEndpoint<LLVMJITLinkChannel>;
using LLVMJITLinkRemoteMemoryManager =
orc::OrcRPCTPCJITLinkMemoryManager<LLVMJITLinkRPCEndpoint>;
using LLVMJITLinkRemoteMemoryAccess =
orc::OrcRPCTPCMemoryAccess<LLVMJITLinkRPCEndpoint>;
class LLVMJITLinkRemoteTargetProcessControl
: public orc::OrcRPCTargetProcessControlBase<LLVMJITLinkRPCEndpoint> {
public:
using BaseT = orc::OrcRPCTargetProcessControlBase<LLVMJITLinkRPCEndpoint>;
static Expected<std::unique_ptr<TargetProcessControl>> LaunchExecutor();
static Expected<std::unique_ptr<TargetProcessControl>> ConnectToExecutor();
Error disconnect() override;
private:
using LLVMJITLinkRemoteMemoryAccess =
orc::OrcRPCTPCMemoryAccess<LLVMJITLinkRemoteTargetProcessControl>;
using LLVMJITLinkRemoteMemoryManager =
orc::OrcRPCTPCJITLinkMemoryManager<LLVMJITLinkRemoteTargetProcessControl>;
LLVMJITLinkRemoteTargetProcessControl(
std::shared_ptr<orc::SymbolStringPool> SSP,
std::unique_ptr<LLVMJITLinkChannel> Channel,
std::unique_ptr<LLVMJITLinkRPCEndpoint> Endpoint,
ErrorReporter ReportError, Error &Err)
: BaseT(std::move(SSP), *Endpoint, std::move(ReportError)),
Channel(std::move(Channel)), Endpoint(std::move(Endpoint)) {
ErrorAsOutParameter _(&Err);
ListenerThread = std::thread([&]() {
while (!Finished) {
if (auto Err = this->Endpoint->handleOne()) {
reportError(std::move(Err));
return;
}
}
});
if (auto Err2 = initializeORCRPCTPCBase()) {
Err = joinErrors(std::move(Err2), disconnect());
return;
}
OwnedMemAccess = std::make_unique<LLVMJITLinkRemoteMemoryAccess>(*this);
MemAccess = OwnedMemAccess.get();
OwnedMemMgr = std::make_unique<LLVMJITLinkRemoteMemoryManager>(*this);
MemMgr = OwnedMemMgr.get();
}
std::unique_ptr<LLVMJITLinkChannel> Channel;
std::unique_ptr<LLVMJITLinkRPCEndpoint> Endpoint;
std::unique_ptr<TargetProcessControl::MemoryAccess> OwnedMemAccess;
std::unique_ptr<jitlink::JITLinkMemoryManager> OwnedMemMgr;
std::atomic<bool> Finished{false};
std::thread ListenerThread;
};
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
struct Session {
std::unique_ptr<orc::TargetProcessControl> TPC;
orc::ExecutionSession ES;
[ORC] Add generic initializer/deinitializer support. Initializers and deinitializers are used to implement C++ static constructors and destructors, runtime registration for some languages (e.g. with the Objective-C runtime for Objective-C/C++ code) and other tasks that would typically be performed when a shared-object/dylib is loaded or unloaded by a statically compiled program. MCJIT and ORC have historically provided limited support for discovering and running initializers/deinitializers by scanning the llvm.global_ctors and llvm.global_dtors variables and recording the functions to be run. This approach suffers from several drawbacks: (1) It only works for IR inputs, not for object files (including cached JIT'd objects). (2) It only works for initializers described by llvm.global_ctors and llvm.global_dtors, however not all initializers are described in this way (Objective-C, for example, describes initializers via specially named metadata sections). (3) To make the initializer/deinitializer functions described by llvm.global_ctors and llvm.global_dtors searchable they must be promoted to extern linkage, polluting the JIT symbol table (extra care must be taken to ensure this promotion does not result in symbol name clashes). This patch introduces several interdependent changes to ORCv2 to support the construction of new initialization schemes, and includes an implementation of a backwards-compatible llvm.global_ctor/llvm.global_dtor scanning scheme, and a MachO specific scheme that handles Objective-C runtime registration (if the Objective-C runtime is available) enabling execution of LLVM IR compiled from Objective-C and Swift. The major changes included in this patch are: (1) The MaterializationUnit and MaterializationResponsibility classes are extended to describe an optional "initializer" symbol for the module (see the getInitializerSymbol method on each class). The presence or absence of this symbol indicates whether the module contains any initializers or deinitializers. The initializer symbol otherwise behaves like any other: searching for it triggers materialization. (2) A new Platform interface is introduced in llvm/ExecutionEngine/Orc/Core.h which provides the following callback interface: - Error setupJITDylib(JITDylib &JD): Can be used to install standard symbols in JITDylibs upon creation. E.g. __dso_handle. - Error notifyAdding(JITDylib &JD, const MaterializationUnit &MU): Generally used to record initializer symbols. - Error notifyRemoving(JITDylib &JD, VModuleKey K): Used to notify a platform that a module is being removed. Platform implementations can use these callbacks to track outstanding initializers and implement a platform-specific approach for executing them. For example, the MachOPlatform installs a plugin in the JIT linker to scan for both __mod_inits sections (for C++ static constructors) and ObjC metadata sections. If discovered, these are processed in the usual platform order: Objective-C registration is carried out first, then static initializers are executed, ensuring that calls to Objective-C from static initializers will be safe. This patch updates LLJIT to use the new scheme for initialization. Two LLJIT::PlatformSupport classes are implemented: A GenericIR platform and a MachO platform. The GenericIR platform implements a modified version of the previous llvm.global-ctor scraping scheme to provide support for Windows and Linux. LLJIT's MachO platform uses the MachOPlatform class to provide MachO specific initialization as described above. Reviewers: sgraenitz, dblaikie Subscribers: mgorny, hiraditya, mgrang, ributzka, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D74300
2019-12-16 11:50:40 +01:00
orc::JITDylib *MainJD;
LLVMJITLinkObjectLinkingLayer ObjLayer;
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
std::vector<orc::JITDylib *> JDSearchOrder;
[ORC] Add support for resource tracking/removal (removable code). This patch introduces new APIs to support resource tracking and removal in Orc. It is intended as a thread-safe generalization of the removeModule concept from OrcV1. Clients can now create ResourceTracker objects (using JITDylib::createResourceTracker) to track resources for each MaterializationUnit (code, data, aliases, absolute symbols, etc.) added to the JIT. Every MaterializationUnit will be associated with a ResourceTracker, and ResourceTrackers can be re-used for multiple MaterializationUnits. Each JITDylib has a default ResourceTracker that will be used for MaterializationUnits added to that JITDylib if no ResourceTracker is explicitly specified. Two operations can be performed on ResourceTrackers: transferTo and remove. The transferTo operation transfers tracking of the resources to a different ResourceTracker object, allowing ResourceTrackers to be merged to reduce administrative overhead (the source tracker is invalidated in the process). The remove operation removes all resources associated with a ResourceTracker, including any symbols defined by MaterializationUnits associated with the tracker, and also invalidates the tracker. These operations are thread safe, and should work regardless of the the state of the MaterializationUnits. In the case of resource transfer any existing resources associated with the source tracker will be transferred to the destination tracker, and all future resources for those units will be automatically associated with the destination tracker. In the case of resource removal all already-allocated resources will be deallocated, any if any program representations associated with the tracker have not been compiled yet they will be destroyed. If any program representations are currently being compiled then they will be prevented from completing: their MaterializationResponsibility will return errors on any attempt to update the JIT state. Clients (usually Layer writers) wishing to track resources can implement the ResourceManager API to receive notifications when ResourceTrackers are transferred or removed. The MaterializationResponsibility::withResourceKeyDo method can be used to create associations between the key for a ResourceTracker and an allocated resource in a thread-safe way. RTDyldObjectLinkingLayer and ObjectLinkingLayer are updated to use the ResourceManager API to enable tracking and removal of memory allocated by the JIT linker. The new JITDylib::clear method can be used to trigger removal of every ResourceTracker associated with the JITDylib (note that this will only remove resources for the JITDylib, it does not run static destructors). This patch includes unit tests showing basic usage. A follow-up patch will update the Kaleidoscope and BuildingAJIT tutorial series to OrcV2 and will use this API to release code associated with anonymous expressions.
2020-09-11 18:50:41 +02:00
~Session();
[ORC] Add generic initializer/deinitializer support. Initializers and deinitializers are used to implement C++ static constructors and destructors, runtime registration for some languages (e.g. with the Objective-C runtime for Objective-C/C++ code) and other tasks that would typically be performed when a shared-object/dylib is loaded or unloaded by a statically compiled program. MCJIT and ORC have historically provided limited support for discovering and running initializers/deinitializers by scanning the llvm.global_ctors and llvm.global_dtors variables and recording the functions to be run. This approach suffers from several drawbacks: (1) It only works for IR inputs, not for object files (including cached JIT'd objects). (2) It only works for initializers described by llvm.global_ctors and llvm.global_dtors, however not all initializers are described in this way (Objective-C, for example, describes initializers via specially named metadata sections). (3) To make the initializer/deinitializer functions described by llvm.global_ctors and llvm.global_dtors searchable they must be promoted to extern linkage, polluting the JIT symbol table (extra care must be taken to ensure this promotion does not result in symbol name clashes). This patch introduces several interdependent changes to ORCv2 to support the construction of new initialization schemes, and includes an implementation of a backwards-compatible llvm.global_ctor/llvm.global_dtor scanning scheme, and a MachO specific scheme that handles Objective-C runtime registration (if the Objective-C runtime is available) enabling execution of LLVM IR compiled from Objective-C and Swift. The major changes included in this patch are: (1) The MaterializationUnit and MaterializationResponsibility classes are extended to describe an optional "initializer" symbol for the module (see the getInitializerSymbol method on each class). The presence or absence of this symbol indicates whether the module contains any initializers or deinitializers. The initializer symbol otherwise behaves like any other: searching for it triggers materialization. (2) A new Platform interface is introduced in llvm/ExecutionEngine/Orc/Core.h which provides the following callback interface: - Error setupJITDylib(JITDylib &JD): Can be used to install standard symbols in JITDylibs upon creation. E.g. __dso_handle. - Error notifyAdding(JITDylib &JD, const MaterializationUnit &MU): Generally used to record initializer symbols. - Error notifyRemoving(JITDylib &JD, VModuleKey K): Used to notify a platform that a module is being removed. Platform implementations can use these callbacks to track outstanding initializers and implement a platform-specific approach for executing them. For example, the MachOPlatform installs a plugin in the JIT linker to scan for both __mod_inits sections (for C++ static constructors) and ObjC metadata sections. If discovered, these are processed in the usual platform order: Objective-C registration is carried out first, then static initializers are executed, ensuring that calls to Objective-C from static initializers will be safe. This patch updates LLJIT to use the new scheme for initialization. Two LLJIT::PlatformSupport classes are implemented: A GenericIR platform and a MachO platform. The GenericIR platform implements a modified version of the previous llvm.global-ctor scraping scheme to provide support for Windows and Linux. LLJIT's MachO platform uses the MachOPlatform class to provide MachO specific initialization as described above. Reviewers: sgraenitz, dblaikie Subscribers: mgorny, hiraditya, mgrang, ributzka, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D74300
2019-12-16 11:50:40 +01:00
static Expected<std::unique_ptr<Session>> Create(Triple TT);
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
void dumpSessionInfo(raw_ostream &OS);
void modifyPassConfig(const Triple &FTT,
jitlink::PassConfiguration &PassConfig);
using MemoryRegionInfo = RuntimeDyldChecker::MemoryRegionInfo;
struct FileInfo {
StringMap<MemoryRegionInfo> SectionInfos;
StringMap<MemoryRegionInfo> StubInfos;
StringMap<MemoryRegionInfo> GOTEntryInfos;
};
using SymbolInfoMap = StringMap<MemoryRegionInfo>;
using FileInfoMap = StringMap<FileInfo>;
Expected<FileInfo &> findFileInfo(StringRef FileName);
Expected<MemoryRegionInfo &> findSectionInfo(StringRef FileName,
StringRef SectionName);
Expected<MemoryRegionInfo &> findStubInfo(StringRef FileName,
StringRef TargetName);
Expected<MemoryRegionInfo &> findGOTEntryInfo(StringRef FileName,
StringRef TargetName);
bool isSymbolRegistered(StringRef Name);
Expected<MemoryRegionInfo &> findSymbolInfo(StringRef SymbolName,
Twine ErrorMsgStem);
SymbolInfoMap SymbolInfos;
FileInfoMap FileInfos;
uint64_t SizeBeforePruning = 0;
uint64_t SizeAfterFixups = 0;
[ORC] Add generic initializer/deinitializer support. Initializers and deinitializers are used to implement C++ static constructors and destructors, runtime registration for some languages (e.g. with the Objective-C runtime for Objective-C/C++ code) and other tasks that would typically be performed when a shared-object/dylib is loaded or unloaded by a statically compiled program. MCJIT and ORC have historically provided limited support for discovering and running initializers/deinitializers by scanning the llvm.global_ctors and llvm.global_dtors variables and recording the functions to be run. This approach suffers from several drawbacks: (1) It only works for IR inputs, not for object files (including cached JIT'd objects). (2) It only works for initializers described by llvm.global_ctors and llvm.global_dtors, however not all initializers are described in this way (Objective-C, for example, describes initializers via specially named metadata sections). (3) To make the initializer/deinitializer functions described by llvm.global_ctors and llvm.global_dtors searchable they must be promoted to extern linkage, polluting the JIT symbol table (extra care must be taken to ensure this promotion does not result in symbol name clashes). This patch introduces several interdependent changes to ORCv2 to support the construction of new initialization schemes, and includes an implementation of a backwards-compatible llvm.global_ctor/llvm.global_dtor scanning scheme, and a MachO specific scheme that handles Objective-C runtime registration (if the Objective-C runtime is available) enabling execution of LLVM IR compiled from Objective-C and Swift. The major changes included in this patch are: (1) The MaterializationUnit and MaterializationResponsibility classes are extended to describe an optional "initializer" symbol for the module (see the getInitializerSymbol method on each class). The presence or absence of this symbol indicates whether the module contains any initializers or deinitializers. The initializer symbol otherwise behaves like any other: searching for it triggers materialization. (2) A new Platform interface is introduced in llvm/ExecutionEngine/Orc/Core.h which provides the following callback interface: - Error setupJITDylib(JITDylib &JD): Can be used to install standard symbols in JITDylibs upon creation. E.g. __dso_handle. - Error notifyAdding(JITDylib &JD, const MaterializationUnit &MU): Generally used to record initializer symbols. - Error notifyRemoving(JITDylib &JD, VModuleKey K): Used to notify a platform that a module is being removed. Platform implementations can use these callbacks to track outstanding initializers and implement a platform-specific approach for executing them. For example, the MachOPlatform installs a plugin in the JIT linker to scan for both __mod_inits sections (for C++ static constructors) and ObjC metadata sections. If discovered, these are processed in the usual platform order: Objective-C registration is carried out first, then static initializers are executed, ensuring that calls to Objective-C from static initializers will be safe. This patch updates LLJIT to use the new scheme for initialization. Two LLJIT::PlatformSupport classes are implemented: A GenericIR platform and a MachO platform. The GenericIR platform implements a modified version of the previous llvm.global-ctor scraping scheme to provide support for Windows and Linux. LLJIT's MachO platform uses the MachOPlatform class to provide MachO specific initialization as described above. Reviewers: sgraenitz, dblaikie Subscribers: mgorny, hiraditya, mgrang, ributzka, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D74300
2019-12-16 11:50:40 +01:00
StringSet<> HarnessFiles;
StringSet<> HarnessExternals;
StringSet<> HarnessDefinitions;
DenseMap<StringRef, StringRef> CanonicalWeakDefs;
[ORC] Add generic initializer/deinitializer support. Initializers and deinitializers are used to implement C++ static constructors and destructors, runtime registration for some languages (e.g. with the Objective-C runtime for Objective-C/C++ code) and other tasks that would typically be performed when a shared-object/dylib is loaded or unloaded by a statically compiled program. MCJIT and ORC have historically provided limited support for discovering and running initializers/deinitializers by scanning the llvm.global_ctors and llvm.global_dtors variables and recording the functions to be run. This approach suffers from several drawbacks: (1) It only works for IR inputs, not for object files (including cached JIT'd objects). (2) It only works for initializers described by llvm.global_ctors and llvm.global_dtors, however not all initializers are described in this way (Objective-C, for example, describes initializers via specially named metadata sections). (3) To make the initializer/deinitializer functions described by llvm.global_ctors and llvm.global_dtors searchable they must be promoted to extern linkage, polluting the JIT symbol table (extra care must be taken to ensure this promotion does not result in symbol name clashes). This patch introduces several interdependent changes to ORCv2 to support the construction of new initialization schemes, and includes an implementation of a backwards-compatible llvm.global_ctor/llvm.global_dtor scanning scheme, and a MachO specific scheme that handles Objective-C runtime registration (if the Objective-C runtime is available) enabling execution of LLVM IR compiled from Objective-C and Swift. The major changes included in this patch are: (1) The MaterializationUnit and MaterializationResponsibility classes are extended to describe an optional "initializer" symbol for the module (see the getInitializerSymbol method on each class). The presence or absence of this symbol indicates whether the module contains any initializers or deinitializers. The initializer symbol otherwise behaves like any other: searching for it triggers materialization. (2) A new Platform interface is introduced in llvm/ExecutionEngine/Orc/Core.h which provides the following callback interface: - Error setupJITDylib(JITDylib &JD): Can be used to install standard symbols in JITDylibs upon creation. E.g. __dso_handle. - Error notifyAdding(JITDylib &JD, const MaterializationUnit &MU): Generally used to record initializer symbols. - Error notifyRemoving(JITDylib &JD, VModuleKey K): Used to notify a platform that a module is being removed. Platform implementations can use these callbacks to track outstanding initializers and implement a platform-specific approach for executing them. For example, the MachOPlatform installs a plugin in the JIT linker to scan for both __mod_inits sections (for C++ static constructors) and ObjC metadata sections. If discovered, these are processed in the usual platform order: Objective-C registration is carried out first, then static initializers are executed, ensuring that calls to Objective-C from static initializers will be safe. This patch updates LLJIT to use the new scheme for initialization. Two LLJIT::PlatformSupport classes are implemented: A GenericIR platform and a MachO platform. The GenericIR platform implements a modified version of the previous llvm.global-ctor scraping scheme to provide support for Windows and Linux. LLJIT's MachO platform uses the MachOPlatform class to provide MachO specific initialization as described above. Reviewers: sgraenitz, dblaikie Subscribers: mgorny, hiraditya, mgrang, ributzka, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D74300
2019-12-16 11:50:40 +01:00
private:
Session(std::unique_ptr<orc::TargetProcessControl> TPC, Error &Err);
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
};
/// Record symbols, GOT entries, stubs, and sections for ELF file.
Error registerELFGraphInfo(Session &S, jitlink::LinkGraph &G);
/// Record symbols, GOT entries, stubs, and sections for MachO file.
Error registerMachOGraphInfo(Session &S, jitlink::LinkGraph &G);
Initial implementation of JITLink - A replacement for RuntimeDyld. Summary: JITLink is a jit-linker that performs the same high-level task as RuntimeDyld: it parses relocatable object files and makes their contents runnable in a target process. JITLink aims to improve on RuntimeDyld in several ways: (1) A clear design intended to maximize code-sharing while minimizing coupling. RuntimeDyld has been developed in an ad-hoc fashion for a number of years and this had led to intermingling of code for multiple architectures (e.g. in RuntimeDyldELF::processRelocationRef) in a way that makes the code more difficult to read, reason about, extend. JITLink is designed to isolate format and architecture specific code, while still sharing generic code. (2) Support for native code models. RuntimeDyld required the use of large code models (where calls to external functions are made indirectly via registers) for many of platforms due to its restrictive model for stub generation (one "stub" per symbol). JITLink allows arbitrary mutation of the atom graph, allowing both GOT and PLT atoms to be added naturally. (3) Native support for asynchronous linking. JITLink uses asynchronous calls for symbol resolution and finalization: these callbacks are passed a continuation function that they must call to complete the linker's work. This allows for cleaner interoperation with the new concurrent ORC JIT APIs, while still being easily implementable in synchronous style if asynchrony is not needed. To maximise sharing, the design has a hierarchy of common code: (1) Generic atom-graph data structure and algorithms (e.g. dead stripping and | memory allocation) that are intended to be shared by all architectures. | + -- (2) Shared per-format code that utilizes (1), e.g. Generic MachO to | atom-graph parsing. | + -- (3) Architecture specific code that uses (1) and (2). E.g. JITLinkerMachO_x86_64, which adds x86-64 specific relocation support to (2) to build and patch up the atom graph. To support asynchronous symbol resolution and finalization, the callbacks for these operations take continuations as arguments: using JITLinkAsyncLookupContinuation = std::function<void(Expected<AsyncLookupResult> LR)>; using JITLinkAsyncLookupFunction = std::function<void(const DenseSet<StringRef> &Symbols, JITLinkAsyncLookupContinuation LookupContinuation)>; using FinalizeContinuation = std::function<void(Error)>; virtual void finalizeAsync(FinalizeContinuation OnFinalize); In addition to its headline features, JITLink also makes other improvements: - Dead stripping support: symbols that are not used (e.g. redundant ODR definitions) are discarded, and take up no memory in the target process (In contrast, RuntimeDyld supported pointer equality for weak definitions, but the redundant definitions stayed resident in memory). - Improved exception handling support. JITLink provides a much more extensive eh-frame parser than RuntimeDyld, and is able to correctly fix up many eh-frame sections that RuntimeDyld currently (silently) fails on. - More extensive validation and error handling throughout. This initial patch supports linking MachO/x86-64 only. Work on support for other architectures and formats will happen in-tree. Differential Revision: https://reviews.llvm.org/D58704 llvm-svn: 358818
2019-04-20 19:10:34 +02:00
} // end namespace llvm
#endif // LLVM_TOOLS_LLVM_JITLINK_LLVM_JITLINK_H