This is a counterpart to ffe2dda29f, and does for scope what that commit did
for linkage.
Making the scope of external definitions visible to JITLink plugins will
allow us to distinguish hidden weak defs (which do not need to be tracked by
default) from default-scoped weak defs (which need to be updated to point at
a single chosen definition at runtime).
Previously we stripped Weak flags from JITDylib symbol table entries once they
were resolved (there was no particularly good reason for this). Now we want to
retain them and query them when setting the Linkage on external symbols in
LinkGraphs during symbol resolution (this was the motivation for 75404e9ef8).
Making weak linkage of external definitions discoverable in the LinkGraph will
in turn allow future plugins to implement correct handling for them (by
recording locations that depend on exported weak definitions and pointing all
of these at one chosen definition at runtime).
Introduces two new methods on Symbol: isWeaklyReferenced and
setWeaklyReferenced. These are now used to track/set whether an external symbol
is weakly referenced, rather than having the Symbol's linkage set to weak.
This change is a first step towards proper handling of weak defs used across
JITDylib boundaries: It frees up the Linkage field on external symbols so that
it can be used to represent the linkage of the definition that the symbol resolves
to. It is expected that Platform plugins will use this information to track
locations that need to be updated if the selected weak definition changes (e.g.
because JITDylibs were dlclosed and then dlopened again in a different order).
I'm planning to deprecate and eventually remove llvm::empty.
I thought about replacing llvm::empty(x) with std::empty(x), but it
turns out that all uses can be converted to x.empty(). That is, no
use requires the ability of std::empty to accept C arrays and
std::initializer_list.
Differential Revision: https://reviews.llvm.org/D133677
This patch updates MachOLinkGraphBuilder to honor the MH_SUBSECTIONS_VIA_SYMBOLS
flag. Prior to this patch we assumed MH_SUBSECTIONS_VIA_SYMBOLS, but never
checked the flag.
If MH_SUBSECTIONS_VIA_SYMBOLS is set (the default for MachO output on modern
compilers) then MachOLinkGraphBuilder will break MachO section content into
jitlink::Blocks on symbol boundaries. (This is how JITLink has always handled
MachO sections previously).
If MH_SUBSECTIONS_VIA_SYMBOLS is not set then MachOLinkGraphBuilder will create
a single jitlink::Block for each MachO section.
Existing hand-written testcases that were _not_ using the
.subsections_via_symbols directive are updated to use it. A new testcase for
non-subsections-via-symbols behavior is included.
I (lhames) accidentally pushed 5f300397c6 on
Kshitij Jain's behalf without updating the patch author first (my apologies
Kshitij!).
Re-applying with correct authorship.
https://reviews.llvm.org/D131347
Add a fix to check that FDE pc-begin targets are defined before calling
getBlock (which will crash if the target is not defined). FDE pc-begins
pointing at undefined symbols are expected to arise only in obscure
circumstances (malformed objects, or removal of targets by JITLink
passes), but we want to handle them gracefully. With this patch the
FDE will be retained, but without any keepalive edge to it. Unless
some pass takes action to mark it as live it will be dead-stripped.
To make it easier for passes to connect FDEs to their targets a new
EHFrameCFIBlockInspector utility is added. This allows clients to
quickly determine whether a CFI record is a CIE or an FDE (assuming
that it's valid), and retrieve any personality, pc-begin, cie, or
LSDA edges associated with it.
Stubs SECREL relocation to external symbol. In order to correctly deal with this, we want to requrest memory manager to keep track of address of first block of sepecific section and keep address to be only increased from that point. We also should give jitlink to get information about global section. The relocation is only used for debug and tls info which we don't support yet anyways, so just stubbing it for now.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130451
Implements SECTION/SECREL relocation. These are used by debug info (pdb) data.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130275
This reverts commit 6ea5bf436a.
6ea5bf436a made use of new c++17 rules regarding
order of evaluation (specifically: in function calls the expression naming the
function should be sequenced before the evalution of any operands) to simplify
some continuation-passing calls. Unfortunately this appears to break at least
one MSVC bot: https://lab.llvm.org/buildbot/#/builders/123/builds/12149 .
Includes an update to the comments to note that the workaround is now based on
MSVC limitations, not on LLVM adopting c++17.
Handles COMDAT symbol with an offset and refactor the code to only generated symbol if the second symbol was encountered. This happens very infrequently but happens in recursive_mutex implementation of MSVC STL library.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130454
Implements remaining IMAGE_REL_AMD64_REL32_*. We only need IMAGE_REL_AMD64_REL32_4 for now but doing all remaining ones for completeness. (clang only uses IMAGE_REL_AMD64_REL32_1 and IMAGE_REL_AMD64_REL32)
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130452
Relax zero-fill edge assertions to only consider relocation edges. Keep-alive edges to zero-fill blocks can cause this assertion which is too strict.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130450
Implements include/alternatename linker directive. Alternatename is used by static msvc runtime library. Alias symbol is technically incorrect (we have to search for external definition) but we don't have a way to represent this in jitlink/orc yet, this is solved in the following up patch.
Inlcude linker directive is used in ucrt to forcelly lookup the static initializer symbols so that they will be emitted. It's implemented as extenral symbols with live flag on that cause the lookup of these symbols.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130276
Implements include/alternatename linker directive. Alternatename is used by static msvc runtime library. Alias symbol is technically incorrect (we have to search for external definition) but we don't have a way to represent this in jitlink/orc yet, this is solved in the following up patch.
Inlcude linker directive is used in ucrt to forcelly lookup the static initializer symbols so that they will be emitted. It's implemented as extenral symbols with live flag on that cause the lookup of these symbols.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130276
Implements dllimport stubs using GOT table manager. Benefit of using GOT table manager is that we can just reuse jitlink-check architecture.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D130175
Adds keep-alive edges to pdata section to prevent dead strip of block when its parent function is alive.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D129945
Implement IMAGE_COMDAT_SELECT_LARGEST partially. It's going to fail if larger symbol appears but this hasn't happened at least in vcruntime library.
We probably would not implement this properly as it requires complicated runtime patching which is not of nature of JIT. However, we'd like to validate if larger section appears and report to the user in the near future.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D129941
Implement IMAGE_WEAK_EXTERN_SEARCH_NOLIBRARY/LIBRARY characteristics flag.
Since COFFObjectFile class will set undefined flag for symbols with no alias flag, ORC ObjectFileInterface will not pull in this symbol. So, we only need to make sure the scope is local. NOLIBRARY and LIBRARY are handled in the same way for now. (which is what lld does right now)
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D129939
Handles duplicate external symbols. This happens in few static libraries generaed from msvc toolchain.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D129937
Reimplements ADDR32NB/REL32 relocations properly, out-of-reach targets will be dealt in the separate patch that will generate the stub for dllimport symbols.
Reviewed By: sgraenitz
Differential Revision: https://reviews.llvm.org/D129936
AcceptedPublic
Implements IMAGE_SYM_CLASS_LABEL. It's simply a section + offset. This is not used a lot by llvm mc but very commonly used by MSVC compiler.
Reviewed By: sgraenitz
Differential Revision: https://reviews.llvm.org/D129754
Handle out-of-order COMDAT second symbols. In llvm codegen, the second symbol of COMDAT sequence always follows the first symbol in the global symbol list. But, when the object file came from MSVC compiler, these can come in out of order.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D129721
This prevents the dead strip of associative comdat section when parent section is alive.
Reviewed By: sgraenitz
Differential Revision: https://reviews.llvm.org/D129720
DWARFRecordSectionSplitter pre-builds a splitBlock cache, but wasn't passing it
to the call to splitBlock. This was an oversight in the original patch.
Adds initial COFF support in JITLink. This is able to run a hello world c program in x86 windows successfully.
Implemented
- COFF object loader
- Static local symbols
- Absolute symbols
- External symbols
- Weak external symbols
- Common symbols
- COFF jitlink-check support
- All COMDAT selection type execpt largest
- Implicit symobl size calculation
- Rel32 relocation with PLT stub.
- IMAGE_REL_AMD64_ADDR32NB relocation
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D128968
(Reapply after revert in e9ce1a5880 due to
Fuchsia test failures. Removed changes in lib/ExecutionEngine/ other
than error categories, to be checked in more detail and reapplied
separately.)
Bulk remove many of the more trivial uses of ManagedStatic in the llvm
directory, either by defining a new getter function or, in many cases,
moving the static variable directly into the only function that uses it.
Differential Revision: https://reviews.llvm.org/D129120
Lang Hames