Commit Graph

416 Commits

Author SHA1 Message Date
Jonas Devlieghere 0eaee545ee [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
2019-08-15 15:54:37 +00:00
Lang Hames 52a34a78d9 [ORC] Refactor definition-generation, add a generator for static libraries.
This patch replaces the JITDylib::DefinitionGenerator typedef with a class of
the same name, and adds support for attaching a sequence of DefinitionGeneration
objects to a JITDylib.

This patch also adds a new definition generator,
StaticLibraryDefinitionGenerator, that can be used to add symbols fom a static
library to a JITDylib. An object from the static library will be added (via
a supplied ObjectLayer reference) whenever a symbol from that object is
referenced.

To enable testing, lli is updated to add support for the --extra-archive option
when running in -jit-kind=orc-lazy mode.

llvm-svn: 368707
2019-08-13 16:05:18 +00:00
Eric Christopher 4acb4ee767 Move findBBwithCalls to the file it's used in to avoid unused function
warnings.

llvm-svn: 368636
2019-08-13 00:05:01 +00:00
Diego Caballero 8bac17709e Re-land D65760/r367944
Fixed most vexing parse ambiguation.

llvm-svn: 368055
2019-08-06 16:24:17 +00:00
Puyan Lotfi 37fe40c330 Reverting D65760/r367944 due to buildbot failure.
http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/15952/steps/build/logs/stdio

JITTargetMachineBuilder.cpp fails to build.

llvm-svn: 367954
2019-08-05 23:47:07 +00:00
Diego Caballero 1647758882 [ORC] Add CPU name and sub-target features to detectHost
This commit adds host CPU name and sub-target features to the
`JITTargetMachineBuilder` created by `JITTargetMachineBuilder::detectHost()`.

Differential Revision: https://reviews.llvm.org/D65760

llvm-svn: 367944
2019-08-05 23:02:12 +00:00
Lang Hames 1707735fa4 [ORC] Work around broken GCC/libstdc++ by adding an explicit conversion.
This should fix the bots that have been failing due to r367712.

llvm-svn: 367921
2019-08-05 20:30:35 +00:00
Praveen Velliengiri f5c40cb900 Speculative Compilation
[ORC] Remove Speculator Variants for Different Program Representations

[ORC] Block Freq Analysis

Speculative Compilation with Naive Block Frequency

Add Applications to OrcSpeculation

ORC v2 with Block Freq Query & Example

Deleted BenchMark Programs

Signed-off-by: preejackie <praveenvelliengiri@gmail.com>

ORCv2 comments resolved

[ORCV2] NFC

ORCv2 NFC

[ORCv2] Speculative compilation - CFGWalkQuery

ORCv2 Adapting IRSpeculationLayer to new locking scheme

llvm-svn: 367756
2019-08-03 14:42:13 +00:00
Lang Hames 10430f4174 [ORC] Remove a dead method.
llvm-svn: 367716
2019-08-02 20:09:30 +00:00
Lang Hames cb391279b4 [ORC] Turn on symbol-flags overrides for LLJIT on Windows by default.
libObject does not apply the Exported flag to symbols in COFF object files,
which can lead to assertions when the symbol flags initially derived from
IR added to the JIT clash with the flags seen by the JIT linker. Both
RTDyldObjectLinkingLayer and ObjectLinkingLayer have a workaround for this:
they can be told to override the flags seen by the linker with the flags
attached to the materialization responsibility object that was passed down
to the linker. This patch modifies LLJIT's setup code to enable this override
by default on platforms where COFF is the default object format.

llvm-svn: 367712
2019-08-02 19:43:20 +00:00
Lang Hames 809e9d1efa [ORC] Change the locking scheme for ThreadSafeModule.
ThreadSafeModule/ThreadSafeContext are used to manage lifetimes and locking
for LLVMContexts in ORCv2. Prior to this patch contexts were locked as soon
as an associated Module was emitted (to be compiled and linked), and were not
unlocked until the emit call returned. This could lead to deadlocks if
interdependent modules that shared contexts were compiled on different threads:
when, during emission of the first module, the dependence was discovered the
second module (which would provide the required symbol) could not be emitted as
the thread emitting the first module still held the lock.

This patch eliminates this possibility by moving to a finer-grained locking
scheme. Each client holds the module lock only while they are actively operating
on it. To make this finer grained locking simpler/safer to implement this patch
removes the explicit lock method, 'getContextLock', from ThreadSafeModule and
replaces it with a new method, 'withModuleDo', that implicitly locks the context,
calls a user-supplied function object to operate on the Module, then implicitly
unlocks the context before returning the result.

ThreadSafeModule TSM = getModule(...);
size_t NumFunctions = TSM.withModuleDo(
    [](Module &M) { // <- context locked before entry to lambda.
      return M.size();
    });

Existing ORCv2 layers that operate on ThreadSafeModules are updated to use the
new method.

This method is used to introduce Module locking into each of the existing
layers.

llvm-svn: 367686
2019-08-02 15:21:37 +00:00
Lang Hames 9e52d0576a [ORC] Suppress an ORCv1 deprecation warning.
llvm-svn: 366485
2019-07-18 19:55:42 +00:00
Lang Hames 1716454027 [ORC] Add deprecation warnings to ORCv1 layers and utilities.
Summary:
ORCv1 is deprecated. The current aim is to remove it before the LLVM 10.0
release. This patch adds deprecation attributes to the ORCv1 layers and
utilities to warn clients of the change.

Reviewers: dblaikie, sgraenitz, AlexDenisov

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64609

llvm-svn: 366344
2019-07-17 16:40:52 +00:00
Lang Hames 843f198a83 [ORC] Add custom IR compiler configuration to LLJITBuilder to enable obj caches.
LLJITBuilder now has a setCompileFunctionCreator method which can be used to
construct a CompileFunction for the LLJIT instance being created. The motivating
use-case for this is supporting ObjectCaches, which can now be set up at
compile-function construction time. To demonstrate this an example project,
LLJITWithObjectCache, is included.

llvm-svn: 365671
2019-07-10 17:24:24 +00:00
Lang Hames f5a885fddd [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
2019-07-04 00:05:12 +00:00
Lang Hames 2f8c6f9362 [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
2019-06-13 20:11:23 +00:00
Lang Hames d4a8089f03 [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
2019-06-07 19:33:51 +00:00
Lang Hames eb5ee3004f [ORC] Track JIT symbol states more explicitly.
Prior to this patch, JITDylibs inferred symbol states (whether a symbol was
newly added, materializing, resolved, or ready to run) via a combination of (1)
bits in the JITSymbolFlags member, and (2) the state of some internal JITDylib
data structures. This patch explicitly tracks symbol states by adding a new
SymbolState member to the symbol table entries, and removing the 'Lazy' and
'Materializing' bits from JITSymbolFlags. This is a first step towards adding
additional states representing initialization phases (e.g. eh-frame registration,
registration with the language runtime, and static initialization).

llvm-svn: 361899
2019-05-28 23:35:44 +00:00
Lang Hames f088e195cc [ORC] Assert that JITDylibs have unique names.
Patch by Praveen Velliengiri. Thanks Praveen!

Differential Revision: https://reviews.llvm.org/D62139

llvm-svn: 361215
2019-05-21 03:23:08 +00:00
Nick Desaulniers 28e351af2a [ORC] fix use-after-move. NFC
Summary:
scan-build flagged a potential use-after-move in debug builds.  It's not
safe that a moved from value contains anything but garbage.  Manually
DRY up these repeated expressions.

Reviewers: lhames

Reviewed By: lhames

Subscribers: hiraditya, llvm-commits, srhines

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62112

llvm-svn: 361203
2019-05-20 22:17:43 +00:00
Lang Hames 0dcf69eb82 [ORC] Remove some unreachable code.
Fixes http://llvm.org/PR41662.

llvm-svn: 361199
2019-05-20 21:30:33 +00:00
Lang Hames c97b50e224 [ORC] Change handling for SymbolStringPtr tombstones and empty keys.
SymbolStringPtr used to use nullptr as its empty value and (since it performed
ref-count operations on any non-nullptr) a pointer to a special pool-entry
instance as its tombstone.

This commit changes the scheme to use two invalid pointer values as the empty
and tombstone values, and broadens the ref-count guard to prevent ref-counting
operations from being performed on these pointers. This should improve the
performance of SymbolStringPtrs used in DenseMaps/DenseSets, as ref counting
operations will no longer be performed on the tombstone.

llvm-svn: 360925
2019-05-16 18:29:34 +00:00
Lang Hames 5fa4e9d990 [ORC] Fix a formatting bug.
llvm-svn: 360382
2019-05-09 22:03:53 +00:00
Lang Hames e4b4ab6d26 [Support] Add error handling to sys::Process::getPageSize().
This patch changes the return type of sys::Process::getPageSize to
Expected<unsigned> to account for the fact that the underlying syscalls used to
obtain the page size may fail (see below).

For clients who use the page size as an optimization only this patch adds a new
method, getPageSizeEstimate, which calls through to getPageSize but discards
any error returned and substitues a "reasonable" page size estimate estimate
instead. All existing LLVM clients are updated to call getPageSizeEstimate
rather than getPageSize.

On Unix, sys::Process::getPageSize is implemented in terms of getpagesize or
sysconf, depending on which macros are set. The sysconf call is documented to
return -1 on failure. On Darwin getpagesize is implemented in terms of sysconf
and may also fail (though the manpage documentation does not mention this).
These failures have been observed in practice when highly restrictive sandbox
permissions have been applied. Without this patch, the result is that
getPageSize returns -1, which wreaks havoc on any subsequent code that was
assuming a sane page size value.

<rdar://problem/41654857>

Reviewers: dblaikie, echristo

Subscribers: kristina, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59107

llvm-svn: 360221
2019-05-08 02:11:07 +00:00
Lang Hames 42a3b4ff0e [ORC] Pass object buffer ownership back in NotifyEmitted.
Clients who want to regain ownership of object buffers after they have been
linked may now use the NotifyEmitted callback for this purpose.

Note: Currently NotifyEmitted is only called if linking succeeds. If linking
fails the buffer is always discarded.

llvm-svn: 359735
2019-05-01 22:40:23 +00:00
Lang Hames 4637e15844 [ORC] Move SimpleCompiler/ConcurrentIRCompiler definitions into a .cpp file.
SimpleCompiler is no longer templated, so there's no reason for this code to be
in a header any more.

llvm-svn: 359626
2019-04-30 22:42:01 +00:00
Lang Hames b12867230c [ORC] Allow JITDylib definition generators to return Errors.
Background: A definition generator can be attached to a JITDylib to generate
new definitions in response to queries. For example: a generator that forwards
calls to dlsym can map symbols from a dynamic library into the JIT process on
demand.

If definition generation fails then the generator should be able to return an
error. This allows the JIT API to distinguish between the case where a
generator does not provide a definition, and the case where it was not able to
determine whether it provided a definition due to an error.

The immediate motivation for this is cross-process symbol lookups: If the
remote-lookup generator is attached to a JITDylib early in the search list, and
if a generator failure is misinterpreted as "no definition in this JITDylib" then
lookup may continue and bind to a different definition in a later JITDylib, which
is a bug.

llvm-svn: 359521
2019-04-30 00:03:26 +00:00
Lang Hames eb14dc7585 [ORC] Replace the LLJIT/LLLazyJIT Create methods with Builder utilities.
LLJITBuilder and LLLazyJITBuilder construct LLJIT and LLLazyJIT instances
respectively. Over time these will allow more configurable options to be
added while remaining easy to use in the default case, which for default
in-process JITing is now:

auto J = ExitOnErr(LLJITBuilder.create());

llvm-svn: 359511
2019-04-29 22:37:27 +00:00
Lang Hames a9fdf375b3 [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
2019-04-26 22:58:39 +00:00
Lang Hames 4f71049a39 [ORC] Remove symbols from dependency lists when failing materialization.
When failing materialization of a symbol X, remove X from the dependants list
of any of X's dependencies. This ensures that when X's dependencies are
emitted (or fail themselves) they do not try to access the no-longer-existing
MaterializationInfo for X.

llvm-svn: 359252
2019-04-25 23:31:33 +00:00
Lang Hames 1233c15be5 [JITLink] Remove a lot of reduntant 'JITLink_' prefixes. NFC.
llvm-svn: 358869
2019-04-22 03:03:09 +00:00
Lang Hames 5004abcd86 [JITLink][ORC] Add JITLink to the list of dependencies for ORC.
The new ObjectLinkingLayer in ORC depends on JITLink.

This should fix the build error at
http://lab.llvm.org:8011/builders/clang-ppc64le-linux-multistage/builds/9621

llvm-svn: 358832
2019-04-20 22:15:57 +00:00
Lang Hames 11c8dfa583 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 17:10:34 +00:00
James Y Knight 14359ef1b6 [opaque pointer types] Pass value type to LoadInst creation.
This cleans up all LoadInst creation in LLVM to explicitly pass the
value type rather than deriving it from the pointer's element-type.

Differential Revision: https://reviews.llvm.org/D57172

llvm-svn: 352911
2019-02-01 20:44:24 +00:00
James Y Knight 7976eb5838 [opaque pointer types] Pass function types to CallInst creation.
This cleans up all CallInst creation in LLVM to explicitly pass a
function type rather than deriving it from the pointer's element-type.

Differential Revision: https://reviews.llvm.org/D57170

llvm-svn: 352909
2019-02-01 20:43:25 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Lang Hames 199a00c3a2 Revert r351138 "[ORC] Move ORC Core symbol map and set types into their own
header: CoreTypes.h."

This commit broke some bots. Reverting while I investigate.

llvm-svn: 351195
2019-01-15 15:21:13 +00:00
Lang Hames ed2df18a48 [ORC] Move ORC Core symbol map and set types into their own header: CoreTypes.h.
This will allow other utilities (including a future RuntimeDyld replacement) to
use these types without pulling in the major Core types (JITDylib, etc.).

llvm-svn: 351138
2019-01-14 23:49:13 +00:00
Simon Atanasyan 789f4154db [ORC][MIPS] Fill delay-slot after `jr` instruction
MIPS `jr` instruction uses a delay-slot. To escape execution of
arbitrary instruction we should either fill the delay-slot by `nop`
instruction or swap `jr` instruction and logically preceding
instruction. This fix implements the second method to generate a bit
more effective code.

llvm-svn: 351001
2019-01-12 11:12:08 +00:00
Simon Atanasyan f903f782e7 [ORC][MIPS] Setup t9 register and call function through this register
MIPS ABI states that every function must be called through jalr $t9. In
other words, a function expect that t9 register points to the beginning
of its code. A function uses this register to calculate offset to the
Global Offset Table and save it to the `gp` register.
```
lui   $gp, %hi(_gp_disp)
addiu $gp, %lo(_gp_disp)
addu  $gp, $gp, $t9
```

If `t9` and as a result `$gp` point to the wrong place the following code
loads incorrect value from GOT and passes control to invalid code.
```
lw    $v0,%call16(foo)($gp)
jalr  $t9
```

OrcMips32 and OrcMips64 writeResolverCode methods pass control to the
resolved address, but do not setup `$t9` before the call. The `t9` holds
value of the beginning of `resolver` code so any attempts to call
routines via GOT failed.

This change fixes the problem. The `OrcLazy/hidden-visibility.ll` test
starts to pass correctly. Before the change it fails on MIPS because the
`exitOnLazyCallThroughFailure` called from the resolver code could not
call libc routine `exit` via GOT.

Differential Revision: http://reviews.llvm.org/D56058

llvm-svn: 351000
2019-01-12 11:12:04 +00:00
Simon Atanasyan 4553cdafe1 [ORC] Rename register in the OrcMips64 resolver code comments. NFC
The `fp` and `s8` register names are synonyms. But `fp` better reflects
a purpose of the register.

llvm-svn: 350023
2018-12-23 12:05:04 +00:00
Simon Atanasyan 15b68b87d5 [ORC] clang-format OrcMips32 and OrcMips64 code. NFC
llvm-svn: 350022
2018-12-23 12:05:00 +00:00
Simon Atanasyan da29981707 [ORC] Remove redundant instruction from MIPS resolver code. NFC
It's redundant to restore the `$a3` register twice.

llvm-svn: 350021
2018-12-23 12:04:55 +00:00
Lang Hames eca6d4b638 [ExecutionEngine] Change NotifyObjectEmitted/NotifyObjectFreed API.
This patch renames both methods (NotifyObjectEmitted -> notifyObjectLoaded, and
NotifyObjectFreed -> notifyObjectFreed), adds an abstract "ObjectKey" (uint64_t)
parameter to notifyObjectLoaded, and replaces the ObjectFile parameter for
notifyObjectFreed with an ObjectKey. Using an ObjectKey to track identify
events, rather than a reference to the ObjectFile, allows us to free the
ObjectFile after notifyObjectLoaded is called, saving memory.

https://reviews.llvm.org/D53773

llvm-svn: 348223
2018-12-04 00:55:15 +00:00
Lang Hames 575515fddf [BuildingAJIT] Update chapter 2 to use the ORCv2 APIs.
llvm-svn: 346726
2018-11-13 01:25:34 +00:00
Lang Hames 91449355f5 [ORC] Fix hex printing of uint64_t values.
A plain "%x" format string will drop the high 32-bits. Use the PRIx64 macro
instead.

llvm-svn: 345696
2018-10-31 05:16:14 +00:00
Matthias Braun 9fd397b423 ADT/STLExtras: Introduce llvm::empty; NFC
This is modeled after C++17 std::empty().

Differential Revision: https://reviews.llvm.org/D53909

llvm-svn: 345679
2018-10-31 00:23:23 +00:00
Lang Hames 23cb2e7f77 [ORC] Re-apply r345077 with fixes to remove ambiguity in lookup calls.
llvm-svn: 345098
2018-10-23 23:01:39 +00:00
Reid Kleckner db367e952e Revert r345077 "[ORC] Change how non-exported symbols are matched during lookup."
Doesn't build on Windows. The call to 'lookup' is ambiguous. Clang and
MSVC agree, anyway.

http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/787
C:\b\slave\clang-x64-windows-msvc\build\llvm.src\unittests\ExecutionEngine\Orc\CoreAPIsTest.cpp(315): error C2668: 'llvm::orc::ExecutionSession::lookup': ambiguous call to overloaded function
C:\b\slave\clang-x64-windows-msvc\build\llvm.src\include\llvm/ExecutionEngine/Orc/Core.h(823): note: could be 'llvm::Expected<llvm::JITEvaluatedSymbol> llvm::orc::ExecutionSession::lookup(llvm::ArrayRef<llvm::orc::JITDylib *>,llvm::orc::SymbolStringPtr)'
C:\b\slave\clang-x64-windows-msvc\build\llvm.src\include\llvm/ExecutionEngine/Orc/Core.h(817): note: or       'llvm::Expected<llvm::JITEvaluatedSymbol> llvm::orc::ExecutionSession::lookup(const llvm::orc::JITDylibSearchList &,llvm::orc::SymbolStringPtr)'
C:\b\slave\clang-x64-windows-msvc\build\llvm.src\unittests\ExecutionEngine\Orc\CoreAPIsTest.cpp(315): note: while trying to match the argument list '(initializer list, llvm::orc::SymbolStringPtr)'

llvm-svn: 345078
2018-10-23 20:54:43 +00:00
Lang Hames 841796decd [ORC] Change how non-exported symbols are matched during lookup.
In the new scheme the client passes a list of (JITDylib&, bool) pairs, rather
than a list of JITDylibs. For each JITDylib the boolean indicates whether or not
to match against non-exported symbols (true means that they should be found,
false means that they should not). The MatchNonExportedInJD and MatchNonExported
parameters on lookup are removed.

The new scheme is more flexible, and easier to understand.

This patch also updates JITDylib search orders to be lists of (JITDylib&, bool)
pairs to match the new lookup scheme. Error handling is also plumbed through
the LLJIT class to allow regression tests to fail predictably when a lookup from
a lazy call-through fails.

llvm-svn: 345077
2018-10-23 20:20:22 +00:00
Lang Hames 3d16af69cf [ORC] Show JITDylib search order in JITDylib::dump.
This can be helpful in debugging search-order related failures.

llvm-svn: 344994
2018-10-23 01:36:32 +00:00
Lang Hames 1aa3292a43 [ORC] Dump flags for JITDylib symbol table entries.
This can help when debugging flag-specific symbol table issues.

llvm-svn: 344993
2018-10-23 01:36:31 +00:00
Lang Hames 95abadec0b [ORC] Guard access to the MemMgrs vector in RTDyldObjectLinkingLayer.
Otherwise we can end up with a data-race when linking concurrently.

This should fix an intermittent failure in the multiple-compile-threads-basic.ll
testcase.

llvm-svn: 344956
2018-10-22 21:17:56 +00:00
Lang Hames 8b94274f22 [ORC] Make the VModuleKey optional, propagate it via MaterializationUnit and
MaterializationResponsibility.

VModuleKeys are intended to enable selective removal of modules from a JIT
session, however for a wide variety of use cases selective removal is not
needed and introduces unnecessary overhead. As of this commit, the default
constructed VModuleKey value is reserved as a "do not track" value, and
becomes the default when adding a new module to the JIT.

This commit also changes the propagation of VModuleKeys. They were passed
alongside the MaterializationResponsibity instance in XXLayer::emit methods,
but are now propagated as part of the MaterializationResponsibility instance
itself (and as part of MaterializationUnit when stored in a JITDylib).
Associating VModuleKeys with MaterializationUnits in this way should allow
for a thread-safe module removal mechanism in the future, even when a module
is in the process of being compiled, by having the
MaterializationResponsibility object check in on its VModuleKey's state
before commiting its results to the JITDylib.

llvm-svn: 344643
2018-10-16 20:13:06 +00:00
Lang Hames 079df9ab2c [ORC] Rename ORC layers to make the "new" ORC layers the default.
This commit adds a 'Legacy' prefix to old ORC layers and utilities, and removes
the '2' suffix from the new ORC layers. If you wish to continue using the old
ORC layers you will need to add a 'Legacy' prefix to your classes. If you were
already using the new ORC layers you will need to drop the '2' suffix.

The legacy layers will remain in-tree until the new layers reach feature
parity with them. This will involve adding support for removing code from the
new layers, and ensuring that performance is comperable.

llvm-svn: 344572
2018-10-15 22:56:10 +00:00
Lang Hames 9f342d9038 [ORC] Rename MultiThreadedSimpleCompiler to ConcurrentIRCompiler.
The new name is a better fit: This class does not actually spawn any new
threads for compilation, it is just safe to call from multiple threads
concurrently.

The "Simple" part of the name did not convey much either, so it was
dropped.

llvm-svn: 344567
2018-10-15 22:36:22 +00:00
Lang Hames 6e66b2a6a3 [ORC] Switch to DenseMap/DenseSet for ORC symbol map/set types.
llvm-svn: 344565
2018-10-15 22:27:02 +00:00
Lang Hames a5157d6f4b [ORC] Simplify naming for JITDylib definition generators.
Renames:
  JITDylib's setFallbackDefinitionGenerator method to setGenerator.
  DynamicLibraryFallbackGenerator class to DynamicLibrarySearchGenerator.
  ReexportsFallbackDefinitionGenerator to ReexportsGenerator.

llvm-svn: 344489
2018-10-15 05:07:54 +00:00
Lang Hames 7899ccbcca [ORC] During lookup, do not match against hidden symbols in other JITDylibs.
This adds two arguments to the main ExecutionSession::lookup method:
MatchNonExportedInJD, and MatchNonExported. These control whether and where
hidden symbols should be matched when searching a list of JITDylibs.

A similar effect could have been achieved by filtering search results, but
this would have involved materializing symbol definitions (since materialization
is triggered on lookup) only to throw the results away, among other issues.

llvm-svn: 344467
2018-10-13 21:53:40 +00:00
Lang Hames bf6603e918 [ORC] Promote and rename private symbols inside the CompileOnDemand layer,
rather than require them to have been promoted before being passed in.

Dropping this precondition is better for layer composition (CompileOnDemandLayer
was the only one that placed pre-conditions on the modules that could be added).
It also means that the promoted private symbols do not show up in the target
JITDylib's symbol table. Instead, they are confined to the hidden implementation
dylib that contains the actual definitions.

For the 403.gcc testcase this cut down the public symbol table size from ~15,000
symbols to ~4000, substantially reducing symbol dependence tracking costs.

llvm-svn: 344078
2018-10-09 20:44:32 +00:00
Lang Hames 535448e08d [ORC] Add a 'remove' method to JITDylib to remove symbols.
Symbols can be removed provided that all are present in the JITDylib and none
are currently in the materializing state. On success all requested symbols are
removed. On failure an error is returned and no symbols are removed.

llvm-svn: 343928
2018-10-06 23:03:59 +00:00
Lang Hames cb5702c3fd [ORC] Pass symbol name to discard by const reference.
This saves some unnecessary atomic ref-counting operations.

llvm-svn: 343927
2018-10-06 23:02:06 +00:00
Lang Hames deb3640d95 [ORC] Pass Symbols to ExecutionSession::lookup by value, potentially saving a
copy.

llvm-svn: 343442
2018-10-01 04:59:10 +00:00
Lang Hames 47d0a37704 [ORC] Add convenience methods for creating DynamicLibraryFallbackGenerators for
libraries on disk, and for the current process.

Avoids more boilerplate during JIT construction.

llvm-svn: 343430
2018-10-01 00:59:28 +00:00
Lang Hames 71d781c434 [ORC] Add an 'intern' method to ExecutionEngine for interning symbol names.
This cuts down on boilerplate by reducing 'ES.getSymbolStringPool().intern(...)'
to 'ES.intern(...)'.

llvm-svn: 343427
2018-09-30 23:18:24 +00:00
Lang Hames d435ce4343 [ORC] Extract and tidy up JITTargetMachineBuilder, add unit test.
(1) Adds comments for the API.

(2) Removes the setArch method: This is redundant: the setArchStr method on the
    triple should be used instead.

(3) Turns EmulatedTLS on by default. This matches EngineBuilder's behavior.

llvm-svn: 343423
2018-09-30 19:12:23 +00:00
Lang Hames 98440293fb [ORC] Add partitioning support to CompileOnDemandLayer2.
CompileOnDemandLayer2 now supports user-supplied partition functions (the
original CompileOnDemandLayer already supported these).

Partition functions are called with the list of requested global values
(i.e. global values that currently have queries waiting on them) and have an
opportunity to select extra global values to materialize at the same time.

Also adds testing infrastructure for the new feature to lli.

llvm-svn: 343396
2018-09-29 23:49:57 +00:00
Lang Hames c3053e41bf [ORC] Clear SymbolToDefinitionMap when materializing a MaterializationUnit.
The map is inaccessible at this point, so we may as well reclaim the memory
early.

llvm-svn: 343395
2018-09-29 23:49:56 +00:00
Lang Hames 2afc22ed9e [ORC] Make MaterializationResponsibility::getRequestedSymbols() const.
This makes it available for use in IRTransformLayer2::TransformFunction
instances (since a const MaterializationResponsibility& parameter was
added in r343365).

llvm-svn: 343367
2018-09-28 22:03:17 +00:00
Lang Hames 3e709d5f78 [ORC] Add more utilities to aid debugging output.
(1) A const accessor for the LLVMContext held by a ThreadSafeContext.

(2) A const accessor for the ThreadSafeModules held by an IRMaterializationUnit.

(3) A const MaterializationResponsibility reference to IRTransformLayer2's
    transform function. This makes IRTransformLayer2 useful for JIT debugging
    (since it can inspect JIT state through the responsibility argument) as well
    as program transformations.

llvm-svn: 343365
2018-09-28 21:49:53 +00:00
Lang Hames b62f73420b [ORC] Narrow a cast: the block guarded by the condition only handles
GlobalVariables, not all GlobalValues.

llvm-svn: 343358
2018-09-28 20:16:16 +00:00
Lang Hames 604769943a [ORC] Remove some dead code.
llvm-svn: 343327
2018-09-28 15:13:41 +00:00
Lang Hames 46f40a7128 [ORC] Improve debugging output for ORC.
(1) Print debugging output under a session lock to avoid garbled messages when
compiling on multiple threads.

(2) Name MaterializationUnits, add an ostream operator for them, and so they can
be easily referenced in debugging output, and have that ostream operator
optionally print code/data/hidden symbols provided by that materialization unit
based on command line options.

llvm-svn: 343323
2018-09-28 15:03:11 +00:00
Lang Hames 4328ea3443 [ORC] clang-format the ThreadSafeModule code.
Evidently I forgot to do this before committing r343055.

llvm-svn: 343288
2018-09-28 01:41:33 +00:00
Lang Hames 8b81395db9 [ORC] Add definition for IRLayer::setCloneToNewContextOnEmit, use it to set the
flag to true in LLJIT when running in multithreaded mode.

The IRLayer::setCloneToNewContextOnEmit method sets a flag within the IRLayer
that causes modules added to that layer to be moved to a new context (by
serializing to/from a memory buffer) when they are emitted. This allows modules
that were all loaded on the same context to be compiled in parallel.

llvm-svn: 343266
2018-09-27 21:13:07 +00:00
Lang Hames c5192f751a [ORC] Coalesce all of ORC's symbol renaming / linkage-promotion utilities into
one SymbolLinkagePromoter utility.

SymbolLinkagePromoter renames anonymous and private symbols, and bumps all
linkages to at least global/hidden-visibility. Modules whose symbols have been
promoted by this utility can be decomposed into sub-modules without introducing
link errors. This is used by the CompileOnDemandLayer to extract single-function
modules for lazy compilation.

llvm-svn: 343257
2018-09-27 19:27:20 +00:00
Lang Hames b57c9c4a6e [ORC] Use ExecutionSession's pre-constructed main JITDylib in LLJIT.
As of r342086 ExecutionSession automatically creates a 'main' JITDylib, so
there is no need for LLJIT to create its own.

llvm-svn: 343167
2018-09-27 04:19:32 +00:00
Lang Hames f0a3fd885d Reapply r343058 with a fix for -DLLVM_ENABLE_THREADS=OFF.
Modifies lit to add a 'thread_support' feature that can be used in lit test
REQUIRES clauses. The thread_support flag is set if -DLLVM_ENABLE_THREADS=ON
and unset if -DLLVM_ENABLE_THREADS=OFF. The lit flag is used to disable the
multiple-compile-threads-basic.ll testcase when threading is disabled.

llvm-svn: 343122
2018-09-26 16:26:59 +00:00
Hans Wennborg 20b5abe23b Revert r343058 "[ORC] Add support for multithreaded compiles to LLJIT and LLLazyJIT."
This doesn't work well in builds configured with LLVM_ENABLE_THREADS=OFF,
causing the following assert when running
ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll:

  lib/ExecutionEngine/Orc/Core.cpp:1748: Expected<llvm::JITEvaluatedSymbol>
  llvm::orc::lookup(const llvm::orc::JITDylibList &, llvm::orc::SymbolStringPtr):
  Assertion `ResultMap->size() == 1 && "Unexpected number of results"' failed.

> LLJIT and LLLazyJIT can now be constructed with an optional NumCompileThreads
> arguments. If this is non-zero then a thread-pool will be created with the
> given number of threads, and compile tasks will be dispatched to the thread
> pool.
>
> To enable testing of this feature, two new flags are added to lli:
>
> (1) -compile-threads=N (N = 0 by default) controls the number of compile threads
> to use.
>
> (2) -thread-entry can be used to execute code on additional threads. For each
> -thread-entry argument supplied (multiple are allowed) a new thread will be
> created and the given symbol called. These additional thread entry points are
> called after static constructors are run, but before main.

llvm-svn: 343099
2018-09-26 12:15:23 +00:00
Lang Hames d8048675f4 [ORC] Update CompileOnDemandLayer2 to use the new lazyReexports mechanism
for lazy compilation, rather than a callback manager.

The new mechanism does not block compile threads, and does not require
function bodies to be renamed.

Future modifications should allow laziness on a per-module basis to work
without any modification of the input module.

llvm-svn: 343065
2018-09-26 05:08:29 +00:00
Lang Hames c1275e72cb [ORC] Add a "lazy call-through" utility based on the same underlying trampoline
implementation as lazy compile callbacks, and a "lazy re-exports" utility that
builds lazy call-throughs.

Lazy call-throughs are similar to lazy compile callbacks (and are based on the
same underlying state saving/restoring trampolines) but resolve their targets
by performing a standard ORC lookup rather than invoking a user supplied
compiler callback. This allows them to inherit the thread-safety of ORC lookups
while blocking only the calling thread (whereas compile callbacks also block one
compile thread).

Lazy re-exports provide a simple way of building lazy call-throughs. Unlike a
regular re-export, a lazy re-export generates a new address (a stub entry point)
that will act like the re-exported symbol when called. The first call via a
lazy re-export will trigger compilation of the re-exported symbol before calling
through to it.

llvm-svn: 343061
2018-09-26 04:18:30 +00:00
Lang Hames 50b3344148 [ORC] Refactor trampoline pool management out of JITCompileCallbackManager.
This will allow trampoline pools to be re-used for a new lazy-reexport utility
that generates looks up function bodies using the standard symbol lookup process
(rather than using a user provided compile function). This new utility provides
the same capabilities (since MaterializationUnits already allow user supplied
compile functions to be run) as JITCompileCallbackManager, but can use the new
asynchronous lookup functions to avoid blocking a compile thread.

This patch also updates createLocalCompileCallbackManager to return an error if
a callback manager can not be created, and updates clients of that API to
account for the change. Finally, the OrcCBindingsStack is updates so that if
a callback manager is not available for the target platform a valid stack
(without support for lazy compilation) can still be constructed.

llvm-svn: 343059
2018-09-26 03:32:12 +00:00
Lang Hames 225a32af72 [ORC] Add support for multithreaded compiles to LLJIT and LLLazyJIT.
LLJIT and LLLazyJIT can now be constructed with an optional NumCompileThreads
arguments. If this is non-zero then a thread-pool will be created with the
given number of threads, and compile tasks will be dispatched to the thread
pool.

To enable testing of this feature, two new flags are added to lli:

(1) -compile-threads=N (N = 0 by default) controls the number of compile threads
to use.

(2) -thread-entry can be used to execute code on additional threads. For each
-thread-entry argument supplied (multiple are allowed) a new thread will be
created and the given symbol called. These additional thread entry points are
called after static constructors are run, but before main.

llvm-svn: 343058
2018-09-26 02:39:42 +00:00
Lang Hames 8d76c71154 [ORC] Add ThreadSafeModule and ThreadSafeContext wrappers to support concurrent
compilation of IR in the JIT.

ThreadSafeContext is a pair of an LLVMContext and a mutex that can be used to
lock that context when it needs to be accessed from multiple threads.

ThreadSafeModule is a pair of a unique_ptr<Module> and a
shared_ptr<ThreadSafeContext>. This allows the lifetime of a ThreadSafeContext
to be managed automatically in terms of the ThreadSafeModules that refer to it:
Once all modules using a ThreadSafeContext are destructed, and providing the
client has not held on to a copy of shared context pointer, the context will be
automatically destructed.

This scheme is necessary due to the following constraits: (1) We need multiple
contexts for multithreaded compilation (at least one per compile thread plus
one to store any IR not currently being compiled, though one context per module
is simpler). (2) We need to free contexts that are no longer being used so that
the JIT does not leak memory over time. (3) Module lifetimes are not
predictable (modules are compiled as needed depending on the flow of JIT'd
code) so there is no single point where contexts could be reclaimed.

JIT clients not using concurrency can safely use one ThreadSafeContext for all
ThreadSafeModules.

JIT clients who want to be able to compile concurrently should use a different
ThreadSafeContext for each module, or call setCloneToNewContextOnEmit on their
top-level IRLayer. The former reduces compile latency (since no clone step is
needed) at the cost of additional memory overhead for uncompiled modules (as
every uncompiled module will duplicate the LLVM types, constants and metadata
that have been shared).

llvm-svn: 343055
2018-09-26 01:24:12 +00:00
Lang Hames abeedf1812 [ORC] Add an asynchronous jit-link function, jitLinkForORC, to RuntimeDyld and
switch RTDyldObjectLinkingLayer2 to use it.

RuntimeDyld::loadObject is currently a blocking operation. This means that any
JIT'd code whose call-graph contains an embedded complete K graph will require
at least K threads to link, which precludes the use of a fixed sized thread
pool for concurrent JITing of arbitrary code (whatever K the thread-pool is set
at, any code with a K+1 complete subgraph will deadlock at JIT-link time).

To address this issue, this commmit introduces a function called jitLinkForORC
that uses continuation-passing style to pass the fix-up and finalization steps
to the asynchronous symbol resolver interface so that linking can be performed
without blocking.

llvm-svn: 343043
2018-09-25 22:57:44 +00:00
Lang Hames adde5ba4b2 [ORC] Reapply r342939 with a fix for MSVC's promise/future restrictions.
llvm-svn: 343012
2018-09-25 19:48:46 +00:00
Lang Hames 99bfa95ae3 Revert "[ORC] Switch to asynchronous resolution in JITSymbolResolver."
This reverts commit r342939.

MSVC's promise/future implementation does not like types that are not default
constructible. Reverting while I figure out a solution.

llvm-svn: 342941
2018-09-25 04:54:03 +00:00
Lang Hames 0e5b60326e [ORC] Switch to asynchronous resolution in JITSymbolResolver.
Asynchronous resolution (where the caller receives a callback once the requested
set of symbols are resolved) is a core part of the new concurrent ORC APIs. This
change extends the asynchronous resolution model down to RuntimeDyld, which is
necessary to prevent deadlocks when compiling/linking on a fixed number of
threads: If RuntimeDyld's linking process were a blocking operation, then any
complete K-graph in a program will require at least K threads to link in the
worst case, as each thread would block waiting for all the others to complete.
Using callbacks instead allows the work to be passed between dependent threads
until it is complete.

For backwards compatibility, all existing RuntimeDyld functions will continue
to operate in blocking mode as before. This change will enable the introduction
of a new async finalization process in a subsequent patch to enable asynchronous
JIT linking.

llvm-svn: 342939
2018-09-25 04:43:38 +00:00
Lang Hames bfd93e5ff6 [ORC] Add some debugging output to Core.h/Core.cpp
Core now logs when materialization units are dispatched or return to JITDylibs.

llvm-svn: 342853
2018-09-23 21:30:05 +00:00
Lang Hames 72d195ecf0 [ORC] Update ORC C bindings to use the new llvm::Error C API.
This replaces instances of the LLVMOrcErrorCode type with LLVMErrorRef,
simplifying the implementation of the OrcCBindingsStack class and ORC
C API bindings and making it possible to return arbitrary (wrapped)
llvm::Errors.

llvm-svn: 342828
2018-09-23 02:09:18 +00:00
Lang Hames 8be0d2e3c2 [ORC] Merge ExecutionSessionBase with ExecutionSession by moving a couple of
template methods in JITDylib out-of-line.

This also splits JITDylib::define into a pair of template methods, one taking an
lvalue reference and the other an rvalue reference. This simplifies the
templates at the cost of a small amount of code duplication.

llvm-svn: 342087
2018-09-12 21:49:02 +00:00
Lang Hames 13014d3ce3 [ORC] Add a special 'main' JITDylib that is created on ExecutionSession
construction, a new convenience lookup method, and add-to layer methods.

ExecutionSession now creates a special 'main' JITDylib upon construction. All
subsequently created JITDylibs are added to the main JITDylib's search order by
default (controlled by the AddToMainDylibSearchOrder parameter to
ExecutionSession::createDylib). The main JITDylib's search order will be used in
the future to properly handle cross-JITDylib weak symbols, with the first
definition in this search order selected.

This commit also adds a new ExecutionSession::lookup convenience method that
performs a blocking lookup using the main JITDylib's search order, as this will
be a very common operation for clients.

Finally, new convenience overloads of IRLayer and ObjectLayer's add methods are
introduced that add the given program representations to the main dylib, which
is likely to be the common case.

llvm-svn: 342086
2018-09-12 21:48:59 +00:00
Petar Jovanovic 5abf4bb552 [MIPS] ORC JIT support
This patch adds support for ORC JIT for mips/mips64 architecture.
In common code $static is changed to __ORCstatic because on MIPS
architecture "$" is a reserved character.

Patch by Luka Ercegovcevic

Differential Revision: https://reviews.llvm.org/D49665

llvm-svn: 341934
2018-09-11 13:10:04 +00:00
Lang Hames afb8b5d954 [ORC] Render unresolved symbol addresses as "<not resolved>" in JITDylib::dump.
This is easier to spot among the real addresses than "0x0000000000000000".

llvm-svn: 341873
2018-09-10 22:09:11 +00:00
Lang Hames 7c4814306d [ORC] Simplify LLJIT::Create by removing the ExecutionSession parameter.
The Create method can just construct the ExecutionSession, rather than having the
client pass it in.

llvm-svn: 341872
2018-09-10 22:08:57 +00:00
Lang Hames bf985258b9 [ORC] Make RuntimeDyldObjectLinkingLayer2 take memory managers by unique_ptr.
The existing memory manager API can not be shared between objects when linking
concurrently (since there is no way to know which concurrent allocations were
performed on behalf of which object, and hence which allocations would be safe
to finalize when finalizeMemory is called). For now, we can work around this by
requiring a new memory manager for each object.

This change only affects the concurrent version of the ORC APIs.

llvm-svn: 341579
2018-09-06 19:39:26 +00:00
Lang Hames a5f33c8694 [ORC] Remove the mapSectionAddress method from RuntimeDyldObjectLinkingLayer2.
Section address mappings can be applied using the RuntimeDyld instance passed to
the RuntimeDyld::MemoryManager::notifyObjectLoaded method. Proving an alternate
route via RuntimeDyldObjectLinkingLayer2 is redundant.

llvm-svn: 341578
2018-09-06 19:39:22 +00:00
Lang Hames b993cf50d6 clang-format r341282.
llvm-svn: 341283
2018-09-02 01:29:29 +00:00
Lang Hames 6a2a889b8a [ORC] Tidy up JITSymbolFlags to remove the need for some explicit static_casts.
Removes the implicit conversion to the underlying type for
JITSymbolFlags::FlagNames and replaces it with some bitwise and comparison
operators.

llvm-svn: 341282
2018-09-02 01:28:26 +00:00
Lang Hames 6d32002e2b [ORC] Add utilities to RTDyldObjectLinkingLayer2 to simplify symbol flag
management and materialization responsibility registration.

The setOverrideObjectFlagsWithResponsibilityFlags method instructs
RTDyldObjectlinkingLayer2 to override the symbol flags produced by RuntimeDyld with
the flags provided by the MaterializationResponsibility instance. This can be used
to enable symbol visibility (hidden/exported) for COFF object files, which do not
currently support the SF_Exported flag.

The setAutoClaimResponsibilityForObjectSymbols method instructs
RTDyldObjectLinkingLayer2 to claim responsibility for any symbols provided by a
given object file that were not already in the MaterializationResponsibility
instance. Setting this flag allows higher-level program representations (e.g.
LLVM IR) to be added based on only a subset of the symbols they provide, without
having to write intervening layers to scan and add the additional symbols. This
trades diagnostic quality for convenience however: If all symbols are enumerated
up-front then clashes can be detected and reported early. If this option is set,
clashes for the additional symbols may not be detected until late, and detection
may depend on the flow of control through JIT'd code.

llvm-svn: 341154
2018-08-31 00:53:17 +00:00