[ORC] Make MaterializationResponsibility immovable, pass by unique_ptr.

Making MaterializationResponsibility instances immovable allows their
associated VModuleKeys to be updated by the ExecutionSes

[ORC] Make MaterializationResponsibility immovable, pass by unique_ptr.

Making MaterializationResponsibility instances immovable allows their
associated VModuleKeys to be updated by the ExecutionSession while the
responsibility is still in-flight. This will be used in the upcoming
removable code feature to enable safe merging of resource keys even if
there are active compiles using the keys being merged.

show more ...

[ORC] Remove an unused variable.

The unused Main variable was accidentally left in an earlier commit.

[ORC][JITLink] Switch to unique ownership for EHFrameRegistrars.

This will make stateful registrars (e.g. a future TargetProcessControl based
registrar) easier to deal with.

[JITLink] Allow JITLinkContext::notifyResolved to return an Error.

This allows clients to detect invalid transformations applied by JITLink passes
(e.g. inserting or removing symbols in unexpected w

[JITLink] Allow JITLinkContext::notifyResolved to return an Error.

This allows clients to detect invalid transformations applied by JITLink passes
(e.g. inserting or removing symbols in unexpected ways) and terminate linking
with an error.

This change is used to simplify the error propagation logic in
ObjectLinkingLayer.

show more ...

[ORC] Enable use of TargetProcessControl::getMemMgr with ObjectLinkingLayer.

This patch makes ownership of the JITLinkMemoryManager by ObjectLinkingLayer
optional: the layer can still own the memory

[ORC] Enable use of TargetProcessControl::getMemMgr with ObjectLinkingLayer.

This patch makes ownership of the JITLinkMemoryManager by ObjectLinkingLayer
optional: the layer can still own the memory manager but no longer has to.

Evevntually we want to move to a state where ObjectLinkingLayer never owns its
memory manager. For now allowing optional ownership makes it easier to develop
classes that can dynamically use either RTDyldObjectLinkingLayer, which owns
its memory managers, or ObjectLinkingLayer (e.g. LLJIT).

show more ...

[ORC] Rename SearchOrder operations on JITDylib to LinkOrder.

Refering to the link order of a dylib better matches the terminology used in
static compilation. As upcoming patches will increase the n

[ORC] Rename SearchOrder operations on JITDylib to LinkOrder.

Refering to the link order of a dylib better matches the terminology used in
static compilation. As upcoming patches will increase the number of places where
link order matters (for example when closing JITDylibs) it's better to get this
name change out of the way early.

show more ...

[ORC] Introduce JITSymbolFlags::HasMaterializeSideEffectsOnly flag.

This flag can be used to mark a symbol as existing only for the purpose of
enabling materialization. Such a symbol can be looked u

[ORC] Introduce JITSymbolFlags::HasMaterializeSideEffectsOnly flag.

This flag can be used to mark a symbol as existing only for the purpose of
enabling materialization. Such a symbol can be looked up to trigger
materialization with the lookup returning only once materialization is
complete. Symbols with this flag will never resolve however (to avoid
permanently polluting the symbol table), and should only be looked up using
the SymbolLookupFlags::WeaklyReferencedSymbol flag. The primary use case for
this flag is initialization symbols.

show more ...

[ORC] Add a mutex to guard EHFrameRegistrationPlugin data structures.

These may be accessed from multiple threads if concurrent materialization is
enabled in ORC.

Testcase coming in a follow-up pat

[ORC] Add a mutex to guard EHFrameRegistrationPlugin data structures.

These may be accessed from multiple threads if concurrent materialization is
enabled in ORC.

Testcase coming in a follow-up patch that enables eh-frame registration for
LLJIT.

show more ...

[ORC] Add errors for missing and extraneous symbol definitions.

This patch adds new errors and error checking to the ObjectLinkingLayer to
catch cases where a compiled or loaded object either:
(1) C

[ORC] Add errors for missing and extraneous symbol definitions.

This patch adds new errors and error checking to the ObjectLinkingLayer to
catch cases where a compiled or loaded object either:
(1) Contains definitions not covered by its responsibility set, or
(2) Is missing definitions that are covered by its responsibility set.

Proir to this patch providing the correct set of definitions was treated as
an API contract requirement, however this requires that the client be confident
in the correctness of the whole compiler / object-cache pipeline and results
in difficult-to-debug assertions upon failure. Treating this as a recoverable
error results in clearer diagnostics.

The performance overhead of this check is one comparison of densemap keys
(symbol string pointers) per linking object, which is minimal. If this overhead
ever becomes a problem we can add the check under a flag that can be turned off
if the client fully trusts the rest of the pipeline.

show more ...

[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

[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

show more ...

[ORC] Fix symbol dependence propagation algorithm in ObjectLinkingLayer.

ObjectLinkingLayer was not correctly propagating dependencies through local
symbols within an object. This could cause symbol

[ORC] Fix symbol dependence propagation algorithm in ObjectLinkingLayer.

ObjectLinkingLayer was not correctly propagating dependencies through local
symbols within an object. This could cause symbol lookup to return before a
searched-for symbol is ready if the following conditions are met:
(1) The definition of the symbol being searched for transitively depends on a
local symbol within the same object, and that local symbol in turn
transitively depends on an external symbol provided by some other module
in the JIT.
(2) Concurrent compilation is enabled.
(3) Thread scheduling causes the lookup of the searched-for symbol to return
before all transitive dependencies of the looked-up symbol are emitted.

This bug was found by inspection and has not been observed in practice.

A jitlink test case has been added to verify that symbol dependencies are
correctly propagated through local symbol definitions.

show more ...

[ORC] Make ObjectLinkingLayer own its jitlink::MemoryManager.

This relieves ObjectLinkingLayer clients of the responsibility of holding the
memory manager. This makes it easier to select between RTD

[ORC] Make ObjectLinkingLayer own its jitlink::MemoryManager.

This relieves ObjectLinkingLayer clients of the responsibility of holding the
memory manager. This makes it easier to select between RTDyldObjectLinkingLayer
(which already owned its memory manager factory) and ObjectLinkingLayer at
runtime as clients aren't required to hold a jitlink::MemoryManager field just
in case ObjectLinkingLayer is selected.

show more ...

[ORC][JITLink] Add support for weak references, and improve handling of static
libraries.

This patch substantially updates ORCv2's lookup API in order to support weak
references, and to better suppo

[ORC][JITLink] Add support for weak references, and improve handling of static
libraries.

This patch substantially updates ORCv2's lookup API in order to support weak
references, and to better support static archives. Key changes:

-- Each symbol being looked for is now associated with a SymbolLookupFlags
value. If the associated value is SymbolLookupFlags::RequiredSymbol then
the symbol must be defined in one of the JITDylibs being searched (or be
able to be generated in one of these JITDylibs via an attached definition
generator) or the lookup will fail with an error. If the associated value is
SymbolLookupFlags::WeaklyReferencedSymbol then the symbol is permitted to be
undefined, in which case it will simply not appear in the resulting
SymbolMap if the rest of the lookup succeeds.

Since lookup now requires these flags for each symbol, the lookup method now
takes an instance of a new SymbolLookupSet type rather than a SymbolNameSet.
SymbolLookupSet is a vector-backed set of (name, flags) pairs. Clients are
responsible for ensuring that the set property (i.e. unique elements) holds,
though this is usually simple and SymbolLookupSet provides convenience
methods to support this.

-- Lookups now have an associated LookupKind value, which is either
LookupKind::Static or LookupKind::DLSym. Definition generators can inspect
the lookup kind when determining whether or not to generate new definitions.
The StaticLibraryDefinitionGenerator is updated to only pull in new objects
from the archive if the lookup kind is Static. This allows lookup to be
re-used to emulate dlsym for JIT'd symbols without pulling in new objects
from archives (which would not happen in a normal dlsym call).

-- JITLink is updated to allow externals to be assigned weak linkage, and
weak externals now use the SymbolLookupFlags::WeaklyReferencedSymbol value
for lookups. Unresolved weak references will be assigned the default value of
zero.

Since this patch was modifying the lookup API anyway, it alo replaces all of the
"MatchNonExported" boolean arguments with a "JITDylibLookupFlags" enum for
readability. If a JITDylib's associated value is
JITDylibLookupFlags::MatchExportedSymbolsOnly then the lookup will only
match against exported (non-hidden) symbols in that JITDylib. If a JITDylib's
associated value is JITDylibLookupFlags::MatchAllSymbols then the lookup will
match against any symbol defined in the JITDylib.

show more ...

[Orc] Add a method for ObjectLinkingLayer to return ownership of object buffers.

RTDyldObjectLinkingLayer allowed clients to register a NotifyEmitted function to
reclaim ownership of object buffers

[Orc] Add a method for ObjectLinkingLayer to return ownership of object buffers.

RTDyldObjectLinkingLayer allowed clients to register a NotifyEmitted function to
reclaim ownership of object buffers once they had been linked. This patch adds
similar functionality to ObjectLinkingLayer: Clients can now optionally call the
ObjectLinkingLayer::setReturnObjectBuffer method to register a function that
will be called when discarding object buffers. If set, this function will be
called to return ownership of the object regardless of whether the link
succeeded or failed.

Use cases for this function include debug dumping (it provides a way to dump
all objects linked into JIT'd code) and object re-use (e.g. storing an
object in a cache).

llvm-svn: 374951

show more ...

[JITLink] Switch from an atom-based model to a "blocks and symbols" model.

In the Atom model the symbols, content and relocations of a relocatable object
file are represented as a graph of atoms, wh

[JITLink] Switch from an atom-based model to a "blocks and symbols" model.

In the Atom model the symbols, content and relocations of a relocatable object
file are represented as a graph of atoms, where each Atom represents a
contiguous block of content with a single name (or no name at all if the
content is anonymous), and where edges between Atoms represent relocations.
If more than one symbol is associated with a contiguous block of content then
the content is broken into multiple atoms and layout constraints (represented by
edges) are introduced to ensure that the content remains effectively contiguous.
These layout constraints must be kept in mind when examining the content
associated with a symbol (it may be spread over multiple atoms) or when applying
certain relocation types (e.g. MachO subtractors).

This patch replaces the Atom model in JITLink with a blocks-and-symbols model.
The blocks-and-symbols model represents relocatable object files as bipartite
graphs, with one set of nodes representing contiguous content (Blocks) and
another representing named or anonymous locations (Symbols) within a Block.
Relocations are represented as edges from Blocks to Symbols. This scheme
removes layout constraints (simplifying handling of MachO alt-entry symbols,
and hopefully ELF sections at some point in the future) and simplifies some
relocation logic.

llvm-svn: 373689

show more ...

[JITLink][ORC] Track eh-frame section size for registration/deregistration.

On MachO, processing of the eh-frame section should stop if the end of the
__eh_frame section is reached, regardless of wh

[JITLink][ORC] Track eh-frame section size for registration/deregistration.

On MachO, processing of the eh-frame section should stop if the end of the
__eh_frame section is reached, regardless of whether or not there is a null CFI
length field at the end of the section. This patch tracks the eh-frame section
size and threads it through the appropriate APIs so that processing can be
terminated correctly.

No testcase yet: This patch is all API plumbing (rather than modification of
linked memory) which the existing infrastructure does not provide a way of
testing. Committing without a testcase until I have an idea of how to write
one.

llvm-svn: 370074

show more ...

[ORC] Fix a FIXME: Propagate errors to dependencies.

When symbols are failed (via MaterializationResponsibility::failMaterialization)
any symbols depending on them will now be moved to an error stat

[ORC] Fix a FIXME: Propagate errors to dependencies.

When symbols are failed (via MaterializationResponsibility::failMaterialization)
any symbols depending on them will now be moved to an error state. Attempting
to resolve or emit a symbol in the error state (via the notifyResolved or
notifyEmitted methods on MaterializationResponsibility) will result in an error.
If notifyResolved or notifyEmitted return an error due to failure of a
dependence then the caller should log or discard the error and call
failMaterialization to propagate the failure to any queries waiting on the
symbols being resolved/emitted (plus their dependencies).

llvm-svn: 369808

show more ...

[llvm] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of

[llvm] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013

show more ...

[JITLink][ORC] Add EHFrameRegistrar interface, use in EHFrameRegistrationPlugin.

Replaces direct calls to eh-frame registration with calls to methods on an
EHFrameRegistrar instance. This allows cli

[JITLink][ORC] Add EHFrameRegistrar interface, use in EHFrameRegistrationPlugin.

Replaces direct calls to eh-frame registration with calls to methods on an
EHFrameRegistrar instance. This allows clients to substitute a registrar that
registers frames in a remote process via IPC/RPC.

llvm-svn: 365098

show more ...

[ORC] Rename MaterializationResponsibility resolve and emit methods to
notifyResolved/notifyEmitted.

The 'notify' prefix better describes what these methods do: they update the JIT
symbol states and

[ORC] Rename MaterializationResponsibility resolve and emit methods to
notifyResolved/notifyEmitted.

The 'notify' prefix better describes what these methods do: they update the JIT
symbol states and notify any pending queries that the 'resolved' and 'emitted'
states have been reached (rather than actually performing the resolution or
emission themselves). Since new states are going to be introduced in the near
future (to track symbol registration/initialization) it's worth changing the
convention pre-emptively to avoid further confusion.

llvm-svn: 363322

show more ...

[ORC] Update symbol lookup to use a single callback with a required symbol state
rather than two callbacks.

The asynchronous lookup API (which the synchronous lookup API wraps for
convenience) used

[ORC] Update symbol lookup to use a single callback with a required symbol state
rather than two callbacks.

The asynchronous lookup API (which the synchronous lookup API wraps for
convenience) used to take two callbacks: OnResolved (called once all requested
symbols had an address assigned) and OnReady to be called once all requested
symbols were safe to access). This patch updates the asynchronous lookup API to
take a single 'OnComplete' callback and a required state (SymbolState) to
determine when the callback should be made. This simplifies the common use case
(where the client is interested in a specific state) and will generalize neatly
as new states are introduced to track runtime initialization of symbols.

Clients who were making use of both callbacks in a single query will now need to
issue two queries (one for SymbolState::Resolved and another for
SymbolState::Ready). Synchronous lookup API clients who were explicitly passing
the WaitOnReady argument will now need neeed to pass a SymbolState instead (for
'WaitOnReady == true' use SymbolState::Ready, for 'WaitOnReady == false' use
SymbolState::Resolved). Synchronous lookup API clients who were using default
arugment values should see no change.

llvm-svn: 362832

show more ...

[ORC] Add a 'plugin' interface to ObjectLinkingLayer for events/configuration.

ObjectLinkingLayer::Plugin provides event notifications when objects are loaded,
emitted, and removed. It also provides

[ORC] Add a 'plugin' interface to ObjectLinkingLayer for events/configuration.

ObjectLinkingLayer::Plugin provides event notifications when objects are loaded,
emitted, and removed. It also provides a modifyPassConfig callback that allows
plugins to modify the JITLink pass configuration.

This patch moves eh-frame registration into its own plugin, and teaches
llvm-jitlink to only add that plugin when performing execution runs on
non-Windows platforms. This should allow us to re-enable the test case that was
removed in r359198.

llvm-svn: 359357

show more ...

[JITLink] Remove a lot of reduntant 'JITLink_' prefixes. NFC.

llvm-svn: 358869

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 mak

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

show more ...