This patch supported the R_X86_64_32S relocation and add the Pointer32Signed generic edge kind.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108446
This patch optimize the GOTPCRELX Reloations, which is described in X86-64 psabi chapter B.2. And Not all optimization of this chapter is implemented.
1. Convert call and jmp has been implemented
2. Convert mov, but the optimization that when the symbol is defined in the lower 32-bit address space, memory operand in `mov` can be convertted into immediate operand has not been implemented.
3. Conver Test and Binop has not been implemented.
The new test file named ELF_got_plt_optimizations.s has been added, and I moved some test cases about optimization of got/plt from ELF_x86_64_small_pic_relocations.s to the new test file.
By referencing the lld, so, the optimization `Convert call and jmp` is not same as what psabi says, and I have explained it in the comment.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108280
This patch unify optimizeELF_x86_64_GOTAndStubs and optimizeMachO_x86_64_GOTAndStubs into a pure optimize_x86_64_GOTAndStubs
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108025
This patch uses a switch statement to map the ELF_x86_64's edge kind to generic edge kind, and merge the ELF_x86_64 's applyFixup function to the x86_64 's applyFixup function. Some edge kinds were not have corresponding generic edge kinds, so I added three generic edge kinds asa follows:
1. RequestGOTAndTransformToDelta64, which is similar to RequestGOTAndTransformToDelta32.
2. GOTDelta64. This generic kind is similar to Delta64, except the GOTDelta64 computes the delta relative to GOTSymbol
3. RequestGOTAndTransformToGOTDelta64. This edge kind was used to deal with ELF_x86_64's GOT64 edge kind, it request the fixGOTEdge function to change the target to GOT entry, and set the edge kind to generic edge kind GOTDelta64.
These added generic edge kinds may named haphazardly, or can't express its meaning well.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D107967
Some files still contained the old University of Illinois Open Source
Licence header. This patch replaces that with the Apache 2 with LLVM
Exception licence.
Differential Revision: https://reviews.llvm.org/D107528
This patch is the initial support, it implements translation from object file to JIT link graph, and very few relocations were supported. Currently, the test file ELF_pc_indirect.s is passed, the HelloWorld program(compiled with mno-relax flag) can be linked correctly and run on instruction emulator correctly.
In the downstream implementation, I have implemented the GOT, PLT function, and EHFrame and some optimization will be implement soon. I will organize the code in to patches, then gradually send it to upstream.
Differential Revision: https://reviews.llvm.org/D105429
This reverts commit 6b2a96285b.
The ccache builders are still failing. Looks like they need to be updated to
get the llvm-zorg config change in 490633945677656ba75d42ff1ca9d4a400b7b243.
I'll re-apply this as soon as the builders are updated.
This reapplies commit a7733e9556 ("Re-apply
[ORC][ORC-RT] Add initial native-TLV support to MachOPlatform."), and
d4abdefc99 ("[ORC-RT] Rename macho_tlv.x86-64.s
to macho_tlv.x86-64.S (uppercase suffix)").
These patches were reverted in 48aa82cacb while I
investigated bot failures (e.g.
https://lab.llvm.org/buildbot/#/builders/109/builds/18981). The fix was to
disable building of the ORC runtime on buliders using ccache (which is the same
fix used for other compiler-rt projects containing assembly code). This fix was
commited to llvm-zorg in 490633945677656ba75d42ff1ca9d4a400b7b243.
This reverts commit d4abdefc99 ("[ORC-RT] Rename
macho_tlv.x86-64.s to macho_tlv.x86-64.S (uppercase suffix)", and
a7733e9556 ("Re-apply "[ORC][ORC-RT] Add initial
native-TLV support to MachOPlatform."), while I investigate failures on
ccache builders (e.g. https://lab.llvm.org/buildbot/#/builders/109/builds/18981)
Reapplies fe1fa43f16, which was reverted in
6d8c63946c, with fixes:
1. Remove .subsections_via_symbols directive from macho_tlv.x86-64.s (it's
not needed here anyway).
2. Return error from pthread_key_create to the MachOPlatform to silence unused
variable warning.
Adds code to LLVM (MachOPlatform) and the ORC runtime to support native MachO
thread local variables. Adding new TLVs to a JITDylib at runtime is supported.
On the LLVM side MachOPlatform is updated to:
1. Identify thread local variables in the LinkGraph and lower them to GOT
accesses to data in the __thread_data or __thread_bss sections.
2. Merge and report the address range of __thread_data and thread_bss sections
to the runtime.
On the ORC runtime a MachOTLVManager class introduced which records the address
range of thread data/bss sections, and creates thread-local instances from the
initial data on demand. An orc-runtime specific tlv_get_addr implementation is
included which saves all register state then calls the MachOTLVManager to get
the address of the requested variable for the current thread.
LinkGraph::transferBlock can be used to move a block and all associated symbols
from one section to another.
LinkGraph::mergeSections moves all blocks and sections from a source section to
a destination section.
ELFLinkGraphBuilder<ELFT> will hold generic parsing and LinkGraph-building code
that can be shared between JITLink ELF backends for different architectures.
For now it's just a stub. The plan is to incrementally move functionality down
from ELFLinkGraphBuilder_x86_64 into the new template.
The C-string section splitting support added in f9649d123d triggered an assert
("Duplicate canonical symbol at address") when multiple symbols were defined at
the the same offset within a C-string block (this triggered on arm64, where we
always add a block start symbol). The bug was caused by a failure to update the
record of the last canonical symbol address. The fix was to maintain this record
correctly, and move the auto-generation of the block-start symbol above the
handling for symbols defined in the object itself so that all symbols
(auto-generated and defined) are processed in address order.
MachO C-string literal sections should be split on null-terminator boundaries,
rather than the usual symbol boundaries. This patch updates
MachOLinkGraphBuilder to do that.
During the generic x86-64 support refactor in ecf6466f01 the implementation
of MachO_arm64_GOTAndStubsBuilder::isGOTEdgeToFix was altered to only return
true for external symbols. This behavior is incorrect: GOT entries may be
required for defined symbols (e.g. in the large code model).
This patch fixes the bug and adds a test case for it (renaming an old test
case to avoid any ambiguity).
This patch introduces new operations on jitlink::Blocks: setMutableContent,
getMutableContent and getAlreadyMutableContent. The setMutableContent method
will set the block content data and size members and flag the content as
mutable. The getMutableContent method will return a mutable copy of the existing
content value, auto-allocating and populating a new mutable copy if the existing
content is marked immutable. The getAlreadyMutableMethod asserts that the
existing content is already mutable and returns it.
setMutableContent should be used when updating the block with totally new
content backed by mutable memory. It can be used to change the size of the
block. The argument value should *not* be shared with any other block.
getMutableContent should be used when clients want to modify the existing
content and are unsure whether it is mutable yet.
getAlreadyMutableContent should be used when clients want to modify the existing
content and know from context that it must already be immutable.
These operations reduce copy-modify-update boilerplate and unnecessary copies
introduced when clients couldn't me sure whether the existing content was
mutable or not.
These can be used to create eh-frame section fixing passes outside the usual
linker pipeline, which can be useful for tests and tools that just want to
verify or dump graphs.
This commit reorders some fields and fixes the width of others to try to
maintain more consistent columns. It also switches to long-hand scope
and linkage names, since LinkGraph dumps aren't read often enough for
single-character codes to be memorable.
Adds utilities for creating anonymous pointers and jump stubs to x86_64.h. These
are used by the GOT and Stubs builder, but may also be used by pass writers who
want to create pointer stubs for indirection.
This patch also switches the underlying type for LinkGraph content from
StringRef to ArrayRef<char>. This avoids any confusion when working with buffers
that contain null bytes in the middle like, for example, a newly added null
pointer content array. ;)
JITLink now requires section names to be unique. In MachO section names are only
guaranteed to be unique within their containing segment (e.g. a '__const' section
in the '__DATA' segment does not clash with a '__const' section in the '__TEXT'
segment), so we need to use the fully qualified <segment>,<section> section
names (e.g. '__DATA,__const' or '__TEXT,__const') when constructing
jitlink::Sections for MachO objects.
Introduces DefineExternalSectionStartAndEndSymbols.h, which defines a template
for a JITLink pass that transforms external symbols meeting a user-supplied
predicate into defined symbols pointing at the start and end of a Section
identified by the predicate. JITLink.h is updated with a new makeAbsolute
function to support this pass.
Also renames BasicGOTAndStubsBuilder to PerGraphGOTAndPLTStubsBuilder -- the new
name better describes the intent of this GOT and PLT stubs builder, and will
help to distinguish it from future GOT and PLT stub builders that build entries
that may be shared between multiple graphs.
Issuing a lookup for an empty symbol set is legal, but can actually result in
unrelated work being done if there was a work queue left over from the previous
lookup. We can avoid doing this unrelated work (reducing stack depth and
interleaving of debugging output) by not issuing these no-op lookups in the
first place.
This patch introduces generic x86-64 edge kinds, and refactors the MachO/x86-64
backend to use these edge kinds. This simplifies the implementation of the
MachO/x86-64 backend and makes it possible to write generic x86-64 passes and
utilities.
The new edge kinds are different from the original set used in the MachO/x86-64
backend. Several edge kinds that were not meaningfully distinguished in that
backend (e.g. the PCRelMinusN edges) have been merged into single edge kinds in
the new scheme (these edge kinds can be reintroduced later if we find a use for
them). At the same time, new edge kinds have been introduced to convey extra
information about the state of the graph. E.g. The Request*AndTransformTo**
edges represent GOT/TLVP relocations prior to synthesis of the GOT/TLVP
entries, and the 'Relaxable' suffix distinguishes edges that are candidates for
optimization from edges which should be left as-is (e.g. to enable runtime
redirection).
ELF/x86-64 will be refactored to use these generic edges at some point in the
future, and I anticipate a similar refactor to create a generic arm64 support
header too.
Differential Revision: https://reviews.llvm.org/D98305
This makes the target triple, graph name, and full graph content available
when making decisions about how to populate the linker pass pipeline.
Also updates the LLJITWithObjectLinkingLayerPlugin example to show more
API use, including use of the API changes in this patch.
GCC warning:
```
In file included from /usr/include/c++/9/cassert:44,
from /home/vsts/work/1/llvm-project/llvm/include/llvm/ADT/BitVector.h:21,
from /home/vsts/work/1/llvm-project/llvm/include/llvm/Support/Program.h:17,
from /home/vsts/work/1/llvm-project/llvm/include/llvm/Support/Process.h:32,
from /home/vsts/work/1/llvm-project/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp:11:
/home/vsts/work/1/llvm-project/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp: In member function ‘virtual llvm::Expected<std::unique_ptr<llvm::jitlink::JITLinkMemoryManager::Allocation> > llvm::jitlink::InProcessMemoryManager::allocate(const llvm::jitlink::JITLinkDylib*, const SegmentsRequestMap&)’:
/home/vsts/work/1/llvm-project/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp:129:40: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
129 | assert(SlabRemaining.allocatedSize() >= 0 && "Mapping exceeds allocation");
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
```
The return type of `allocatedSize()` is `size_t`, thus the expression
`SlabRemaining.allocatedSize() >= 0` always evaluate to `true`.
This is required for ELF where PCRel32 doesn't implicitly subtract 4.
No test case yet: I haven't figured out a good way to test stub
generation -- this may required extensions to jitlink-check.
Adds the EHFrameSplitter and EHFrameEdgeFixer passes to the default JITLink
pass pipeline for ELF/x86-64, and teaches EHFrameEdgeFixer to handle some
new pointer encodings.
Together these changes enable exception handling (at least for the basic
cases that I've tested so far) for ELF/x86-64 objects loaded via JITLink.
Previously FDE field names were used, but the fixup kind used for a field can
vary based on the pointer encoding.
This change will improve readability / maintainability when EH-frame support is
added to JITLink/ELF.
Passes in the new PostAllocationPasses list will run immediately after memory
allocation and address assignment for defined symbols, and before
JITLinkContext::notifyResolved is called. These passes can set up state
associated with the addresses of defined symbols before any query for these
addresses completes.
PreFixupPasses better reflects when these passes will run.
A future patch will (re)introduce a PostAllocationPasses list that will run
after allocation, but before JITLinkContext::notifyResolved is called to notify
the rest of the JIT about the resolved symbol addresses.
Separates link graph creation from linking. This allows raw LinkGraphs to be
created and passed to a link. ObjectLinkingLayer is updated to support emission
of raw LinkGraphs in addition to object buffers.
Raw LinkGraphs can be created by in-memory compilers to bypass object encoding /
decoding (though this prevents caching, as LinkGraphs have do not have an
on-disk representation), and by utility code to add programatically generated
data structures to the JIT target process.
JITLinkDylib represents a target dylib for a JITLink link. By representing this
explicitly we can:
- Enable JITLinkMemoryManagers to manage allocations on a per-dylib basis
(e.g by maintaining a seperate allocation pool for each JITLinkDylib).
- Enable new features and diagnostics that require information about the
target dylib (not implemented in this patch).
Distinguish objects by target properties address size, endian and machine architecture. So far we only
support x86-64 (ELFCLASS64, ELFDATA2LSB, EM_X86_64).
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D90860
This reverts commit c6ef6e1690.
Basically, publicly linked libraries have a different semantic than components,
which link libraries privately.
Differential Revision: https://reviews.llvm.org/D91461
Use LINK_COMPONENTS instead of explicit target_link_libraries for components.
This avoids redundancy and potential inconsistencies.
Differential Revision: https://reviews.llvm.org/D91461
No longer rely on an external tool to build the llvm component layout.
Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.
These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.
Differential Revision: https://reviews.llvm.org/D90848
implementation.
This patch aims to improve support for out-of-process JITing using OrcV2. It
introduces two new class templates, OrcRPCTargetProcessControlBase and
OrcRPCTPCServer, which together implement the TargetProcessControl API by
forwarding operations to an execution process via an Orc-RPC Endpoint. These
utilities are used to implement out-of-process JITing from llvm-jitlink to
a new llvm-jitlink-executor tool.
This patch also breaks the OrcJIT library into three parts:
-- OrcTargetProcess: Contains code needed by the JIT execution process.
-- OrcShared: Contains code needed by the JIT execution and compiler
processes
-- OrcJIT: Everything else.
This break-up allows JIT executor processes to link against OrcTargetProcess
and OrcShared only, without having to link in all of OrcJIT. Clients executing
JIT'd code in-process should start linking against OrcTargetProcess as well as
OrcJIT.
In the near future these changes will enable:
-- Removal of the OrcRemoteTargetClient/OrcRemoteTargetServer class templates
which provided similar functionality in OrcV1.
-- Restoration of Chapter 5 of the Building-A-JIT tutorial series, which will
serve as a simple usage example for these APIs.
-- Implementation of lazy, cross-target compilation in lli's -jit-kind=orc-lazy
mode.
The macro HAVE_EHTABLE_SUPPORT is used by parts of ExecutionEngine to tell __register_frame/__deregister_frame is available to register the
FDE for a generated (JIT) code. It's currently set by a slowly growing set of macro tests in the respective headers, which is updated now and then when it fails to link on some platform or another due to the symbols being missing (see for example https://bugs.llvm.org/show_bug.cgi?id=5715).
This change converts the macro in two HAVE_(DE)REGISTER_FRAME config.h macros (like most of the other HAVE_* macros) and set's them based on whether CMake can actually find a definition for these symbols to link to at configuration time.
Reviewed By: hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D87114
Basic implementation for call and jmp branches with 32 bit offset. Branches to local targets produce
Branch32 edges that are resolved like a regular PCRel32 relocations. Branches to external (undefined)
targets produce Branch32ToStub edges and go through a PLT entry by default. If the target happens to
get resolved within the 32 bit range from the callsite, the edge is relaxed during post-allocation
optimization. There is a test for each of these cases.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D90331
We have been producing R_X86_64_REX_GOTPCRELX (MOV64rm/TEST64rm/...) and
R_X86_64_GOTPCRELX for CALL64m/JMP64m without the REX prefix since 2016 (to be
consistent with GNU as), but not for MOV32rm/TEST32rm/...
Symbols with special section index SHN_COMMON (0xfff2) haven't been handled so far and caused an invalid section error.
This is a more or less straightforward use of the code commented out at the end of the function. I checked with the ELF spec, that the symbol value gives the alignment.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D89795
The difference is that the former are indirect and go to the GOT while the latter go to the target directly. This info can be used to relax indirect ones that don't need the GOT (because the target is in range). We check for this optimization beforehand. For formal correctness and to avoid confusion, we should only change the relocation kind if we actually apply the relaxation.
This re-applies e2fceec2fd with fixes. Apparently we already *do* support
relaxation for ELF, so we need to make sure the test case allocates a slab at
a fixed address, and that the R_X86_64_REX_GOTPCRELX test references an external
that is guaranteed to be out of range.
This patch enables basic BSS section handling, and improves a couple of error
messages in the ELF section parsing code.
Patch by Christian Schafmeister. Thanks Christian!
Differential Revision: https://reviews.llvm.org/D88867
`ELFFile<ELFT>` has many methods that take pointers,
though they assume that arguments are never null and
hence could take references instead.
This patch performs such clean-up.
Differential revision: https://reviews.llvm.org/D87385
The functions `__register_frame`/`__deregister_frame` are not
available on z/OS, so add a guard to not use them.
Reviewed By: lhames, abhina.sreeskantharajan
Differential Revision: https://reviews.llvm.org/D84787
MachOLinkGraphBuilder has been treating these as hidden, but they should be
treated as local.
Symbols with N_PEXT set and N_EXT unset are produced when hidden symbols are
run through 'ld -r' without passing -keep_private_externs. They will show up
under 'nm -m' as "was private extern", hence the name of the test cases.
Testcase commited as relocatable object to ensure that the test suite doesn't
depend on having 'ld -r' available.
Correctly sign extend the addend, and fix implicit shift operand decoding
(it incorrectly returned 0 for some cases), and check that the initial
encoded immediate is 0.
The -phony-externals option adds a generator which explicitly defines any
otherwise unresolved externals as null. This transforms link-time
unresolved-symbol errors into potential runtime null pointer accesses
(if an unresolved external is actually accessed during execution).
This option can be useful in -harness mode to avoid having to mock a
large number of symbols that are not reachable at runtime (e.g. unused
methods referenced by a class vtable).
The -harness option enables new testing use-cases for llvm-jitlink. It takes a
list of objects to treat as a test harness for any regular objects passed to
llvm-jitlink.
If any files are passed using the -harness option then the following
transformations are applied to all other files:
(1) Symbols definitions that are referenced by the harness files are promoted
to default scope. (This enables access to statics from test harness).
(2) Symbols definitions that clash with definitions in the harness files are
deleted. (This enables interposition by test harness).
(3) All other definitions in regular files are demoted to local scope.
(This causes untested code to be dead stripped, reducing memory cost and
eliminating spurious unresolved symbol errors from untested code).
These transformations allow the harness files to reference and interpose
symbols in the regular object files, which can be used to support execution
tests (including fuzz tests) of functions in relocatable objects produced by a
build.
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.
Identify relocations by (section name, offset) pairs, rather than plain
vmaddrs. This makes it easier to cross-reference debugging output for
relocations with output from standard object inspection tools (otool,
readelf, objdump, etc.).
When processing a MachO SUBTRACTOR/UNSIGNED pair, if the UNSIGNED target
is non-extern then check the r_symbolnum field of the relocation to find
the targeted section and use the section's address to find 'ToSymbol'.
Previously 'ToSymbol' was found by loading the initial value stored at
the fixup location and treating this as an address to search for. This
is incorrect, however: the initial value includes the addend and will
point to the wrong block if the addend is less than zero or greater than
the block size.
rdar://65756694
Summary: This adds the basic support for GOT in elf x86.
Was able to just get away using the macho code by generalising the edges.
There will be a follow up patch to turn that into a generic utility for both of the x86 and Mach-O code.
This patch also lands support for relocations relative to symbol.
Reviewers: lhames
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83748
Debug sections will not be linked into the final executable and may contain
ambiguous relocations*. Skipping them avoids both some unnecessary processing
cost and the hassle of dealing with the problematic relocations.
* E.g. __debug_ranges contains non-extern relocations to the end of functions
hat begin with named symbols. Under the usual rules for interpreting non-extern
relocations these will be incorrectly associated with the following block, or
no block at all (if there is a gap between one block and the next).
Summary:
Adding in our first relocation type, and all the required plumbing to support the rest in following patches
Differential Revision: https://reviews.llvm.org/D80613
Reviewer: lhames
This patch adds a jitlink pass, 'registerELFGraphInfo', that records section
and symbol information about each LinkGraph in the llvm-jitlink session object.
This allows symbols and sections to be referred to by name in llvm-jitlink
regression tests. This will enable a testcase to be written for
https://reviews.llvm.org/D80613.
This initial implementation supports section and symbol parsing, but no
relocation support. It enables JITLink to link and execute ELF relocatable
objects that do not require relocations.
Patch by Jared Wyles. Thanks Jared!
Differential Revision: https://reviews.llvm.org/D79832
This patch changes Block::removeEdge to return a valid iterator to the new next
element, and uses this to update the edge removal algorithm in
LinkGraph::splitBlock.
This removes the conditional layout of relocation_info bitfields that was
introduced in 3ccd677bf (svn r358839). The platform relocation_info
struct (defined in usr/include/mach-o/reloc.h) does not define the layout of
this struct differently on big-endian platforms and we want to keep the LLVM
and platform definitions in sync.
To fix the bug that 3ccd677bf addressed this patch modifies JITLink to construct
its relocation_info structs from the raw relocation words using shift and mask
operations.
Global symbols with linker-private prefixes should be resolvable across object
boundaries, but internal symbols with linker-private prefixes should not.
reinterpret_cast'ing the block base address directly to a uint64_t leaves the
high bits in an implementation-defined state, but JITLink expects them to be
zero. Switching to pointerToJITTargetAddress for the cast should fix this.
This should fix the jitlink test failures that we have seen on some of the
32-bit testers.
This optimization bypasses GOT loads and calls/branches through stubs when the
ultimate target of the access/branch is found to be within range of the
reference.
Extra debugging output is also added to the generic JITLink algorithm and
basic GOT and Stubs builder utility to aid debugging.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
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.
Summary:
Most libraries are defined in the lib/ directory but there are also a
few libraries defined in tools/ e.g. libLLVM, libLTO. I'm defining
"Component Libraries" as libraries defined in lib/ that may be included in
libLLVM.so. Explicitly marking the libraries in lib/ as component
libraries allows us to remove some fragile checks that attempt to
differentiate between lib/ libraries and tools/ libraires:
1. In tools/llvm-shlib, because
llvm_map_components_to_libnames(LIB_NAMES "all") returned a list of
all libraries defined in the whole project, there was custom code
needed to filter out libraries defined in tools/, none of which should
be included in libLLVM.so. This code assumed that any library
defined as static was from lib/ and everything else should be
excluded.
With this change, llvm_map_components_to_libnames(LIB_NAMES, "all")
only returns libraries that have been added to the LLVM_COMPONENT_LIBS
global cmake property, so this custom filtering logic can be removed.
Doing this also fixes the build with BUILD_SHARED_LIBS=ON
and LLVM_BUILD_LLVM_DYLIB=ON.
2. There was some code in llvm_add_library that assumed that
libraries defined in lib/ would not have LLVM_LINK_COMPONENTS or
ARG_LINK_COMPONENTS set. This is only true because libraries
defined lib lib/ use LLVMBuild.txt and don't set these values.
This code has been fixed now to check if the library has been
explicitly marked as a component library, which should now make it
easier to remove LLVMBuild at some point in the future.
I have tested this patch on Windows, MacOS and Linux with release builds
and the following combinations of CMake options:
- "" (No options)
- -DLLVM_BUILD_LLVM_DYLIB=ON
- -DLLVM_LINK_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_BUILD_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_LINK_LLVM_DYLIB=ON
Reviewers: beanz, smeenai, compnerd, phosek
Reviewed By: beanz
Subscribers: wuzish, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, mgorny, mehdi_amini, sbc100, jgravelle-google, hiraditya, aheejin, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, dang, Jim, lenary, s.egerton, pzheng, sameer.abuasal, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70179
Some targets (E.g. MachO/arm64) use relocations to fix some CFI record fields
in the eh-frame section. When relocations are used the initial (pre-relocation)
content of the eh-frame section can no longer be interpreted by following the
eh-frame specification. This causes errors in the existing eh-frame parser.
This patch moves eh-frame handling into two LinkGraph passes that are run after
relocations have been parsed (but before they are applied). The first] pass
breaks up blocks in the eh-frame section into per-CFI-record blocks, and the
second parses blocks of (potentially multiple) CFI records and adds the
appropriate edges to any CFI fields that do not have existing relocations.
These passes can be run independently of one another. By handling eh-frame
splitting/fixing with LinkGraph passes we can both re-use existing relocations
for CFI record fields and avoid applying eh-frame fixups before parsing the
section (which would complicate the linker and require extra temporary
allocations of working memory).
LinkGraph::splitBlock will split a block at a given index, returning a new
block covering the range [ 0, index ) and modifying the original block to
cover the range [ index, original-block-size ). Block addresses, content,
edges and symbols will be updated as necessary. This utility will be used
in upcoming improvements to JITLink's eh-frame support.
Sections may have zero size and zero-sized sections may share a start address
with other zero-sized sections. For the section overlap test to function
correctly zero-sized sections must be ordered before any non-zero sized ones.
This should fix the intermittent failures in the
test/ExecutionEngine/JITLink/X86/MachO_zero_fill_alignment.s test case that
have been observed on some builders.
InProcessMemoryManager used to make separate memory allocation calls for each
permission level (RW, RX, RO), which could lead to target-out-of-range errors
if data and code were placed too far apart (this was the source of failures in
the JITLink/AArch64 testcase when it was first landed).
This patch updates InProcessMemoryManager to allocate a single slab which is
subdivided between text and data. This should guarantee that accesses remain
in-range provided that individual object files do not exceed 1Mb in size.
This patch also re-enables the JITLink/AArch64 testcase.
llvm-svn: 374948
This implementation has support for all relocation types except TLV.
Compact unwind sections are not yet supported, so exceptions/unwinding will not
work.
llvm-svn: 374476
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
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
If content sections have lower alignment than zero-fill sections then bump the
overall segment alignment to avoid under-aligning the zero-fill sections.
llvm-svn: 370072
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
Changes: no changes. A fix for the clang code will be landed right on top.
Original commit message:
SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.
For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)
This patch makes a change for all users to switch to Expected<> version.
Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).
Differential revision: https://reviews.llvm.org/D66089
llvm-svn: 368826
SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.
For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)
This patch makes a change for all users to switch to Expected<> version.
Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).
Differential revision: https://reviews.llvm.org/D66089
llvm-svn: 368812
luxufan