GCC will accept any case for assembler directives.
For example ".abort" and ".ABORT" (even ".aBoRt")
are equivalent.
https://sourceware.org/binutils/docs/as/Pseudo-Ops.html#Pseudo-Ops
"The names are case insensitive for most targets,
and usually written in lower case."
Change llvm-mc to accept any case for generic directives
or aliases of those directives.
This for Bugzilla #39527.
Differential Revision: https://reviews.llvm.org/D72686
When compiling position-independent executables, we now use
DW_EH_PE_pcrel | DW_EH_PE_sdata4. However, the MIPS ABI does not define a
64-bit PC-relative ELF relocation so we cannot use sdata8 for the large
code model case. When using the large code model, we fall back to the
previous behaviour of generating absolute relocations.
With this change clang-generated .o files can be linked by LLD without
having to pass -Wl,-z,notext (which creates text relocations).
This is simpler than the approach used by ld.bfd, which rewrites the
.eh_frame section to convert absolute relocations into relative references.
I saw in D13104 that apparently ld.bfd did not accept pc-relative relocations
for MIPS ouput at some point. However, I also checked that recent ld.bfd
can process the clang-generated .o files so this no longer seems true.
Reviewed By: atanasyan
Differential Revision: https://reviews.llvm.org/D72228
For a target symbol defined in the same section, currently we don't emit
a relocation if VariantKind is VK_None (with few exceptions like RISC-V
relaxation), while GNU as emits one. This causes program behavior
differences with and without -ffunction-sections, and can break intended
symbol interposition in a -shared link.
```
.globl foo
foo:
call foo # no relocation. On other targets, may be written as b foo, etc
call bar # a relocation if bar is in another section (e.g. -ffunction-sections)
call foo@plt # a relocation
```
Unify these cases by always emitting a relocation. If we ever want to
optimize `call foo` in -shared links, we should emit a STB_LOCAL alias
and call via the alias.
ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does.
X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does.
ELF/relax.s: rewrite the test as target-in-same-section.s .
We omitted relocations to `global` and now emit R_X86_64_PLT32.
Note, GNU as does not emit a relocation for `jmp global` (maybe its own
bug). Our new behavior is compatible except `jmp global`.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D72197
The argument is llvm::null() everywhere except llvm::errs() in
llvm-objdump in -DLLVM_ENABLE_ASSERTIONS=On builds. It is used by no
target but X86 in -DLLVM_ENABLE_ASSERTIONS=On builds.
If we ever have the needs to add verbose log to disassemblers, we can
record log with a member function, instead of passing it around as an
argument.
Summary:
Extend D71677 to apply to all branch-target operands, rather than special-casing call instructions.
Also add a regression test for llvm.org/PR44272, since this finishes fixing it.
Reviewers: thakis, rnk
Reviewed By: thakis
Subscribers: merge_guards_bot, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D72417
`APFLoat::convertFromString` returns `Expected` result, which must be
"checked" if the LLVM_ENABLE_ABI_BREAKING_CHECKS preprocessor flag is
set.
To mark an `Expected` result as "checked" we must consume the `Error`
within.
In many cases, we are only interested in knowing if an error occured,
without the need to examine the error info. This is achieved, easily,
with the `errorToBool()` API.
As discussed heavily in the original review (D70157), there's a need for the compiler to be able to selective suppress padding (either nop or prefix) to respect assumptions about the meaning of labels and instructions in generated code.
Rather than wait for syntax to be finalized - which appears to be a very slow process - this patch focuses on the compiler use case and *only* worries about the integrated assembler. To my knowledge, this covers all cases mentioned to date for clang/JIT support.
For testing purposes, I wired it up so that if the integrated assembler was using autopadding for branch alignment (e.g. enabled at command line) then the textual assembly output would contain a comment for each location where padding was enabled or disabled. This seemed like the least painful choice overall.
Note that the result of this patch effective disables the jcc errata mitigation for many constructs (statepoints, implicit null checks, xray, etc...) which is non ideal. It is at least *correct* and should allow us to enable the mitigation for the compiler. Once that's done, and a few other items are worked through, we probably want to come back to this an explore a bundling based approach instead so that we can pad instructions while keeping labels in the right place.
Differential Revision: https://reviews.llvm.org/D72303
Silence (clang/MSVC) static analyzer warnings that the fragment data may either write out of bounds of the local array or reference uninitialized data.
printInst prints a branch/call instruction as `b offset` (there are many
variants on various targets) instead of `b address`.
It is a convention to use address instead of offset in most external
symbolizers/disassemblers. This difference makes `llvm-objdump -d`
output unsatisfactory.
Add `uint64_t Address` to printInst(), so that it can pass the argument to
printInstruction(). `raw_ostream &OS` is moved to the last to be
consistent with other print* methods.
The next step is to pass `Address` to printInstruction() (generated by
tablegen from the instruction set description). We can gradually migrate
targets to print addresses instead of offsets.
In any case, downstream projects which don't know `Address` can pass 0 as
the argument.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D72172
sizeof(MCFragment) does not change, but some if its subclasses do, e.g.
on a 64-bit platform,
sizeof(MCEncodedFragment) decreases from 64 to 56,
sizeof(MCDataFragment) decreases from 224 to 216.
This simplifies the generic interface and also makes SHF_ARM_PURECODE
more robust (fixes a TODO). Inspecting MCDataFragment contents covers
more cases than MCObjectStreamer::EmitBytes.
clang/lib/CodeGen/CodeGenModule performs the -mpie-copy-relocations
check and sets dso_local on applicable global variables. We don't need
to duplicate the work in TargetMachine shouldAssumeDSOLocal.
Verified that -mpie-copy-relocations can still emit PC relative
relocations for external variable accesses.
clang -target x86_64 -fpie -mpie-copy-relocations -c => R_X86_64_PC32
clang -target aarch64 -fpie -mpie-copy-relocations -c => R_AARCH64_ADR_PREL_PG_HI21+R_AARCH64_LDST64_ABS_LO12_NC
Summary:
Amend MS offset operator implementation, to more closely fit with its MS counterpart:
1. InlineAsm: evaluate non-local source entities to their (address) location
2. Provide a mean with which one may acquire the address of an assembly label via MS syntax, rather than yielding a memory reference (i.e. "offset asm_label" and "$asm_label" should be synonymous
3. address PR32530
Based on http://llvm.org/D37461
Fix broken test where the break appears unrelated.
- Set up appropriate memory-input rewrites for variable references.
- Intel-dialect assembly printing now correctly handles addresses by adding "offset".
- Pass offsets as immediate operands (using "r" constraint for offsets of locals).
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D71436
This reverts commit 7ca86ee6494d4307333b300bae80e42df4a5140f.
Apparently this change causes MS link.exe to error out with
"LNK1235: corrupt or invalid COFF symbol table".
If we have references to the same extern_weak in multiple objects,
all of them would generate external symbols with the same name. Make
them static to avoid duplicate definitions; nothing should need to
refer to this symbol outside of the current object.
GCC/binutils seems to handle the same by not using a fixed string
for the ".default" suffix, but instead using the name of some other
defined external symbol from the same object (which is supposed to
be unique among objects unless there's other duplicate definitions).
Differential Revision: https://reviews.llvm.org/D71711
Summary:
This is documented as the appropriate template modifier for call operands.
Fixes PR44272, and adds a regression test.
Also adds support for operand modifiers in Intel-style inline assembly.
Reviewers: rnk
Reviewed By: rnk
Subscribers: merge_guards_bot, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D71677
WARNING: If you're looking at this patch because you're looking for a full
performace mitigation of the Intel JCC Erratum, this is not it!
This is a preliminary patch on the patch towards mitigating the performance
regressions caused by Intel's microcode update for Jump Conditional Code
Erratum. For context, see:
https://www.intel.com/content/www/us/en/support/articles/000055650.html
The patch adds the required assembler infrastructure and command line options
needed to exercise the logic for INTERNAL TESTING. These are NOT public flags,
and should not be used for anything other than LLVM's own testing/debugging
purposes. They are likely to change both in spelling and meaning.
WARNING: This patch is knowingly incorrect in some cornercases. We need, and
do not yet provide, a mechanism to selective enable/disable the padding.
Conversation on this will continue in parellel with work on extending this
infrastructure to support prefix padding.
The goal here is to have the assembler align specific instructions such that
they neither cross or end at a 32 byte boundary. The impacted instructions are:
a. Conditional jump.
b. Fused conditional jump.
c. Unconditional jump.
d. Indirect jump.
e. Ret.
f. Call.
The new options for llvm-mc are:
-x86-align-branch-boundary=NUM aligns branches within NUM byte boundary.
-x86-align-branch=TYPE[+TYPE...] specifies types of branches to align.
A new MCFragment type, MCBoundaryAlignFragment, is added, which may emit
NOP to align the fused/unfused branch.
alignBranchesBegin inserts MCBoundaryAlignFragment before instructions,
alignBranchesEnd marks the end of the branch to be aligned,
relaxBoundaryAlign grows or shrinks sizes of NOP to align the target branch.
Nop padding is disabled when the instruction may be rewritten by the linker,
such as TLS Call.
Process Note: I am landing a patch by skan as it has been LGTMed, and
continuing to iterate on the review is simply slowing us down at this point.
We can and will continue to iterate in tree.
Patch By: skan
Differential Revision: https://reviews.llvm.org/D70157
Summary:
When we use undefined symbol with its qualname, we are not able
to generate that symbol because of the logic of early "continue"
that skip the qualname symbol. This patch fixes it.
Differential revision: https://reviews.llvm.org/D71667
(This commit restores the original branch (4272372c571) and applies an
additional change dropped from the original in a bad merge. This change
should address the previous bot failures. Both changes reviewed by pete.)
Summary:
This commit builds upon Derek Schuff's 2014 commit for attaching labels to
existing fragments ( Diff Revision: http://reviews.llvm.org/D5915 )
When temporary labels appear ahead of a fragment, MCObjectStreamer will
track the temporary label symbol in a "Pending Labels" list. Labels are
associated with fragments when a real fragment arrives; otherwise, an empty
data fragment will be created if the streamer's section changes or if the
stream finishes.
This commit moves the "Pending Labels" list into each MCStream, so that
this label-fragment matching process is resilient to section changes. If
the streamer emits a label in a new section, switches to another section to
do other work, then switches back to the first section and emits a
fragment, that initial label will be associated with this new fragment.
Labels will only receive empty data fragments in the case where no other
fragment exists for that section.
The downstream effects of this can be seen in Mach-O relocations. The
previous approach could produce local section relocations and external
symbol relocations for the same data in an object file, and this mix of
relocation types resulted in problems in the ld64 Mach-O linker. This
commit ensures relocations triggered by temporary labels are consistent.
Reviewers: pete, ab, dschuff
Reviewed By: pete, dschuff
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71368
This reverts commit 4272372c571cd33edc77a8844b0a224ad7339138.
Caused an MSan buildbot failure. More information available in the patch
that introduced the bug: https://reviews.llvm.org/D71368
added a test case for macinfo.dwo emission."
This was reverted in caa412090666c10f854322cdc701c1cbf8ed726e,
since it was causing an assertion failure on Windows bots.
This revision is revised to fix that.
Original commit message -
[DebugInfo] Refactored macro related generation, added a test case for macinfo.dwo emission.
Reviewers: dblaikie, aprantl, jini.susan.george
Tags: #debug-info #llvm
Differential Revision: https://reviews.llvm.org/D71008
Summary:
This commit builds upon Derek Schuff's 2014 commit for attaching labels to
existing fragments ( Diff Revision: http://reviews.llvm.org/D5915 )
When temporary labels appear ahead of a fragment, MCObjectStreamer will
track the temporary label symbol in a "Pending Labels" list. Labels are
associated with fragments when a real fragment arrives; otherwise, an empty
data fragment will be created if the streamer's section changes or if the
stream finishes.
This commit moves the "Pending Labels" list into each MCStream, so that
this label-fragment matching process is resilient to section changes. If
the streamer emits a label in a new section, switches to another section to
do other work, then switches back to the first section and emits a
fragment, that initial label will be associated with this new fragment.
Labels will only receive empty data fragments in the case where no other
fragment exists for that section.
The downstream effects of this can be seen in Mach-O relocations. The
previous approach could produce local section relocations and external
symbol relocations for the same data in an object file, and this mix of
relocation types resulted in problems in the ld64 Mach-O linker. This
commit ensures relocations triggered by temporary labels are consistent.
Reviewers: pete, ab, dschuff
Reviewed By: pete, dschuff
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71368
MCSymbolRefExpr::getVariantKindForName does not return VK_WEAKREF, so this code path is not exercised. Moreoever, .weakref is probably a feature that nobody uses.
This is equivalent to the existing `import_name` and `import_module`
attributes which control the import names in the final wasm binary
produced by lld.
This maps the existing
This attribute currently requires a string rather than using the
symbol name for a couple of reasons:
1. Avoid confusion with static and dynamic linking which is
based on symbol name. Exporting a function from a wasm module using
this directive is orthogonal to both static and dynamic linking.
2. Avoids name mangling.
Differential Revision: https://reviews.llvm.org/D70520
SUMMARY:
Fixed a bug of XCOFFObjectFile.cpp when there is padding at the last csect of a sections.
when there is a tail padding of a section, but the value of CurrentAddressLocation do not be increased by the padding size. it will hit assert assert(CurrentAddressLocation == Section->Address && "We should have no padding between sections.");
Reviewers: daltenty,hubert.reinterpretcast,
Differential Revision: https://reviews.llvm.org/D70859
D34393 added MCCodePadder as an infrastructure for padding code with
NOP instructions. It lacked tests and was not being worked on since
then.
Intel has now worked on an assembler patch to mitigate performance loss
after applying microcode update for the Jump Conditional Code Erratum.
https://www.intel.com/content/www/us/en/support/articles/000055650/processors.html
This new patch shares similarity with MCCodePadder, but has a concrete
use case in mind and is being actively developed. The infrastructure it
introduces can potentially be used for general performance improvement
via alignment. Delete the unused MCCodePadder so that people can develop
the new feature from a clean state.
Reviewed By: jyknight, skan
Differential Revision: https://reviews.llvm.org/D71106
Before this change, the *InstPrinter.cpp files of each target where some
of the slowest objects to compile in all of LLVM. See this snippet produced by
ClangBuildAnalyzer:
https://reviews.llvm.org/P8171$96
Search for "InstPrinter", and see that it shows up in a few places.
Tablegen was emitting a large switch containing a sequence of operand checks,
each of which created many conditions and many BBs. Register allocation and
jump threading both did not scale well with such a large repetitive sequence of
basic blocks.
So, this change essentially turns those control flow structures into
data. The previous structure looked like:
switch (Opc) {
case TGT::ADD:
// check alias 1
if (MI->getOperandCount() == N && // check num opnds
MI->getOperand(0).isReg() && // check opnd 0
...
MI->getOperand(1).isImm() && // check opnd 1
AsmString = "foo";
break;
}
// check alias 2
if (...)
...
return false;
The new structure looks like:
OpToPatterns: Sorted table of opcodes mapping to pattern indices.
\->
Patterns: List of patterns. Previous table points to subrange of
patterns to match.
\->
Conds: The if conditions above encoded as a kind and 32-bit value.
See MCInstPrinter.cpp for the details of how the new data structures are
interpreted.
Here are some before and after metrics.
Time to compile AArch64InstPrinter.cpp:
0m29.062s vs. 0m2.203s
size of the obj:
3.9M vs. 676K
size of clang.exe:
97M vs. 96M
I have not benchmarked disassembly performance, but typically
disassemblers are bottlenecked on IO and string processing, not alias
matching, so I'm not sure it's interesting enough to be worth doing.
Reviewers: RKSimon, andreadb, xbolva00, craig.topper
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D70650
SUMMARY:
if the size of Csect is zero, the Csect do not need write any data into sections
for example, the TOC Csect has zero size, it do not need invoke a
Asm.writeSectionData(W.OS, Csect.MCCsect, Layout);
Reviewers: daltenty
Subscribers: rupprecht, seiyai,hiraditya
Differential Revision: https://reviews.llvm.org/D71120
Summary:
Implement emitTCEntry for PPCTargetXCOFFStreamer.
Add TC csects to TOCCsects for object file writing.
Note:
1. I did not include any raw data testing for this object file generation
because TC entries raw data will all be 0 without relocation implemented.
I will add raw data testing as part of relocation testing later.
2. I removed "Symbol->setFragment(F);" for common symbols because we
don't need it, and if we have it then we would hit assertions below:
Assertion `(SymbolContents == SymContentsUnset ||
SymbolContents == SymContentsOffset) &&
"Cannot get offset for a common/variable symbol"' failed.
3.Fixed incorrect TOC-base alignment.
Differential Revision: https://reviews.llvm.org/D70798
This patch adds support for debug_macinfo.dwo section[pre-standardized]
to llvm and llvm-dwarfdump.
Reviewers: probinson, dblaikie, aprantl, jini.susan.george, alok
Differential Revision: https://reviews.llvm.org/D70705
Tags: #debug-info #llvm
Summary:
Emit the correct .toc psuedo op when we change to the TOC and emit
TC entries. Make sure TOC psuedos get the right symbols via overriding
getMCSymbolForTOCPseudoMO on AIX. Add a test for TOC assembly writing
and update tests to include TOC entries.
Also make sure external globals have a csect set and handle external function descriptor (originally authored by Jason Liu) so we can emit TOC entries for them.
Reviewers: DiggerLin, sfertile, Xiangling_L, jasonliu, hubert.reinterpretcast
Reviewed By: jasonliu
Subscribers: arphaman, wuzish, nemanjai, hiraditya, kbarton, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70461
The third parameter to Streamer.EmitSymbolValue() is "bool
IsSectionRelative = false".
For ELF, these debug sections are mapped to address zero, so a normal,
absolute address relocation works just fine, but COFF needs a section
relative relocation, and COFF is the only target where
needsDwarfSectionOffsetDirective() returns true. This matches how
EmitSymbolValue is called elsewhere in the same source file.
Differential Revision: https://reviews.llvm.org/D70661
Summary:
This patch sets up the infrastructure for
1. Associate MCSymbolXCOFF with an MCSectionXCOFF when it could not
get implicitly associated.
2. Generate undefined symbols. The patch itself generates undefined symbol
for external function call only. Generate undefined symbol for external
global variable and external function descriptors will be handled in
separate patch(s) after this is land.
Differential Revision: https://reviews.llvm.org/D70443
