Commit Graph

791 Commits

Author SHA1 Message Date
Fangrui Song 59ff9315fd [MC][ARM] Support .reloc *, BFD_RELOC_{NONE,8,16,32}, *
BFD_RELOC_NONE is useful for ld --gc-sections: it provides a generic way indicating a dependency between two sections.
2021-03-05 21:39:16 -08:00
Oliver Stannard aac056c528 [objdump][ARM] Use correct offset when printing ARM/Thumb branch targets
llvm-objdump only uses one MCInstrAnalysis object, so if ARM and Thumb
code is mixed in one object, or if an object is disassembled without
explicitly setting the triple to match the ISA used, then branch and
call targets will be printed incorrectly.

This could be fixed by creating two MCInstrAnalysis objects in
llvm-objdump, like we currently do for SubtargetInfo. However, I don't
think there's any reason we need two separate sub-classes of
MCInstrAnalysis, so instead these can be merged into one, and the ISA
determined by checking the opcode of the instruction.

Differential revision: https://reviews.llvm.org/D97766
2021-03-04 11:15:57 +00:00
Stefan Agner a921aaf789 [MC][ARM] make Thumb function also if type attribute is set
Make sure to set the bottom bit of the symbol even when the type
attribute of a label is set after the label.

GNU as sets the thumb state according to the thumb state of the label.
If a .type directive is placed after the label, set the symbol's thumb
state according to the thumb state of the .type directive. This matches
GNU as in most cases.

From: Stefan Agner <stefan@agner.ch>

This fixes:
https://bugs.llvm.org/show_bug.cgi?id=44860
https://github.com/ClangBuiltLinux/linux/issues/866

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D74927
2021-02-24 14:08:56 -08:00
Sjoerd Meijer e1c3bf6afe [ARM] do not consider sp as deprecated for ldm/stm
Early versions of the ARMv7 reference manuals considered the sp register
as a deprecated register for ldm/stm familiy of instructions. However,
later versions such as ARM DDI 0406C.d added a note to the Appendix:

D9.3 Use of the SP as a general-purpose register
Most ARM instructions, unlike Thumb instructions, provide exactly the
same access to the SP as to R0-R12. This means that it is possible to
use the SP as a general-purpose register.  Earlier issues of this manual
deprecated the use of SP in an ARM instruction, in any way that is
deprecated, not permitted, or not possible in the corresponding
Thumb instruction. However, user feedback indicates a number of cases
where these instructions are useful. Therefore, ARM no longer deprecates
these instruction uses.
Also Armv8 manuals no longer consider SP as deprecated register for ldm/
stm A32 instructions.

Furthermore, GNU as also does not print a deprecated warning when using
SP with those instructions.

Drop deprecation warning for pop/ldm/push/stm instructions.

Patch by: Stefan Agner.

Differential Revision: https://reviews.llvm.org/D82692
2021-02-23 13:26:18 +00:00
Petr Hosek 16af973933 [MC][ELF] Support for zero flag section groups
This change introduces support for zero flag ELF section groups to LLVM.
LLVM already supports COMDAT sections, which in ELF are a special type
of ELF section groups. These are generally useful to enable linker GC
where you want a group of sections to always travel together, that is to
be either retained or discarded as a whole, but without the COMDAT
semantics. Other ELF assemblers already support zero flag ELF section
groups and this change helps us reach feature parity.

Differential Revision: https://reviews.llvm.org/D95851
2021-02-16 14:23:40 -08:00
Dan Gohman 698c6b0a09 [WebAssembly] Support single-floating-point immediate value
As mentioned in TODO comment, casting double to float causes NaNs to change bits.
To avoid the change, this patch adds support for single-floating-point immediate value on MachineCode.

Patch by Yuta Saito.

Differential Revision: https://reviews.llvm.org/D77384
2021-02-04 18:05:06 -08:00
Kazu Hirata f890fd5f91 [llvm] Use llvm::is_sorted (NFC) 2021-01-27 23:25:39 -08:00
Fangrui Song 7b9890e17e [MC][ELF] Remove unneeded MCSymbol::setExternal calls
ELF code uses symbol bindings and does not call isExternal().
2020-12-20 21:26:36 -08:00
Florian Hahn b2f4c5fddc
[AsmWriter] Factor out mnemonic generation to accessible getMnemonic.
This patch factors out the part of printInstruction that gets the
mnemonic string for a given MCInst. This is intended to be used
subsequently for the instruction-mix remarks to display the final
mnemonic (D90040).

Unfortunately making `getMnemonic` available to the AsmPrinter
seems to require making it virtual. Not sure if there's a way around
that with the current layering of the AsmPrinters.

Reviewed By: Paul-C-Anagnostopoulos

Differential Revision: https://reviews.llvm.org/D90039
2020-11-17 09:47:38 +00:00
serge-sans-paille 9218ff50f9 llvmbuildectomy - replace llvm-build by plain cmake
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
2020-11-13 10:35:24 +01:00
Evgeny Leviant 7a78073be7 [ARM][SchedModels] Let ldm* instruction scheduling use MCSchedPredicate
Differential revision: https://reviews.llvm.org/D89957
2020-10-23 10:33:20 +03:00
Evgeny Leviant ed6a91f456 [ARM][SchedModels] Convert IsLdstsoScaledPred to MCSchedPredicate
Differential revision: https://reviews.llvm.org/D89939
2020-10-22 18:03:01 +03:00
Evgeny Leviant 991e86156c [ARM][SchedModels] Convert IsCPSRDefinedPred to MCSchedPredicate
Differential revision: https://reviews.llvm.org/D89460
2020-10-20 11:14:21 +03:00
Luqman Aden 51892a42da [COFF][ARM] Fix CodeView for Windows on 32bit ARM targets.
Create the LLVM / CodeView register mappings for the 32-bit ARM Window targets.

Reviewed By: compnerd

Differential Revision: https://reviews.llvm.org/D89622
2020-10-19 22:16:16 -07:00
Evgeny Leviant 8a7ca143f8 [ARM][SchedModels] Convert IsPredicatedPred to MCSchedPredicate
Differential revision: https://reviews.llvm.org/D89553
2020-10-19 11:37:54 +03:00
David Green f4c5cadbcb [ARM] Select f32 constants with vmov.f16
This adds lowering for f32 values using the vmov.f16, which zeroes the
top bits whilst setting the lower bits to a pattern. This range of
values does not often come up, except where a f16 constant value has
been converted to a f32.

Differential Revision: https://reviews.llvm.org/D87790
2020-09-21 11:10:47 +01:00
Craig Topper c7a0b2684f [X86][MC][Target] Initial backend support a tune CPU to support -mtune
This patch implements initial backend support for a -mtune CPU controlled by a "tune-cpu" function attribute. If the attribute is not present X86 will use the resolved CPU from target-cpu attribute or command line.

This patch adds MC layer support a tune CPU. Each CPU now has two sets of features stored in their GenSubtargetInfo.inc tables . These features lists are passed separately to the Processor and ProcessorModel classes in tablegen. The tune list defaults to an empty list to avoid changes to non-X86. This annoyingly increases the size of static tables on all target as we now store 24 more bytes per CPU. I haven't quantified the overall impact, but I can if we're concerned.

One new test is added to X86 to show a few tuning features with mismatched tune-cpu and target-cpu/target-feature attributes to demonstrate independent control. Another new test is added to demonstrate that the scheduler model follows the tune CPU.

I have not added a -mtune to llc/opt or MC layer command line yet. With no attributes we'll just use the -mcpu for both. MC layer tools will always follow the normal CPU for tuning.

Differential Revision: https://reviews.llvm.org/D85165
2020-08-14 15:31:50 -07:00
Martin Storsjö 5eedc01a82 [ARM, AArch64] Fix a comment typo. NFC. 2020-08-06 09:23:45 +03:00
Sjoerd Meijer 85342c27a3 [ARM] Optimize immediate selection
Optimize some specific immediates selection by materializing them with sub/mvn
instructions as opposed to loading them from the constant pool.

Patch by Ben Shi, powerman1st@163.com.

Differential Revision: https://reviews.llvm.org/D83745
2020-07-29 13:29:17 +01:00
Simon Wallis 3e0ccf9a90 [ARM] halfword store hits llvm_unreachable with big-endian
Summary:
[ARM] halfword store hits llvm_unreachable with big-endian

Provide missing case in getFixupKindContainerSizeBytes().

This stops execution reaching llvm_unreachable("Unknown fixup kind!")

D83947

Reviewers: olista01, ostannard

Reviewed By: ostannard

Subscribers: ostannard, kristof.beyls, hiraditya, danielkiss, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83947

Change-Id: I598aa1fb51fd1c6f424c557c85d6df6d1958bc62
2020-07-17 08:56:44 +01:00
Stefan Agner b7d41a11cd [ARM] Make cp10 and cp11 usage a warning
The ARM ARM considers p10/p11 valid arguments for MCR/MRC instructions.
MRC instructions with p10 arguments are also used in kernel code which
is shared for different architectures. Turn usage of p10/p11 to warnings
for ARMv7/ARMv8-M.

Reviewers: rengolin, olista01, t.p.northover, efriedma, psmith, simon_tatham

Reviewed By: simon_tatham

Subscribers: hiraditya, danielkiss, jcai19, tpimh, nickdesaulniers, peter.smith, javed.absar, kristof.beyls, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59733
2020-06-24 23:37:54 +02:00
Eric Christopher 8116d01905 Typos around a -> an. 2020-06-20 14:04:48 -07:00
Eric Christopher cf23852587 [Target] As part of using inclusive language within the llvm project,
migrate away from the use of blacklist and whitelist.

This change affects an internal llvm command line option.
2020-06-20 00:06:39 -07:00
Fangrui Song 773f8dbd1d [MC] Fix double negation of DW_CFA_def_cfa
Negations are incorrectly added in numerous places and the code just happens to work.
Also fix a missed DW_CFA_def_cfa_offset negation in c693b9c321d5a40d012340619674cf790c9ac86c:
ARMAsmBackendDarwin::generateCompactUnwindEncoding
2020-05-22 21:02:53 -07:00
Fangrui Song 7e49dc6184 [MC] Change MCCFIInstruction::createDefCfa to cfiDefCfa which does not negate Offset
The negative Offset has caused a bunch of problems and confused quite a
few call sites. Delete the unneeded negation and fix all call sites.
2020-05-22 15:47:26 -07:00
Simon Wallis 410644fbf7 Clang crash targeting ARM or Thumb when assembling a prel31 relocation variant
Summary:
In the assembler or inline assembler,
attempting to use an invalid fixup type
gives a crash with a segmentation fault.

__attribute__((naked))
void foo(void) {
 __asm__("mov r9, :lower16:bar(prel31)");
}

This should give a proper error message when building for ARM or Thumb.
This brings it in line with AARCH64.

This fixes all 8 instances of llvm_unreachable("Unsupported Modifier");
in ARM/MCTargetDesc/ARMELFObjectWriter.cpp.
A test is provided for each instance.

Reviewers: llvm-commits, MarkMurrayARM

Reviewed By: MarkMurrayARM

Subscribers: kristof.beyls, hiraditya, danielkiss

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79782

Change-Id: I6971ba37f129cc453568fe71514ccb2ac9d16831
2020-05-13 13:52:30 +01:00
Dimitry Andric fc373522b0 [arm] Add big-endian version of pcrel fixups for adr instructions
Summary:
In 2e24219d3c, a number of ARM pcrel fixups were resolved at assembly
time, to solve PR44929. This only covered little-endian ARM however, so
add similar fixups for big-endian ARM. Also extend the test case to
cover big-endian ARM.

Reviewers: hans, psmith, MaskRay

Reviewed By: psmith, MaskRay

Subscribers: kristof.beyls, hiraditya, danielkiss, emaste, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79774
2020-05-12 19:27:48 +02:00
Fangrui Song 3c9c9c1768 [llvm-objdump] Print target address with evaluateMemoryOperandAddress()
D63847 added `MCInstrAnalysis::evaluateMemoryOperandAddress()`. This patch
leverages the feature to print the target addresses for evaluable instructions.

```
-400a: movl 4080(%rip), %eax
+400a: movl 4080(%rip), %eax  # 5000 <data1>
```

This patch also deletes `MIA->isCall(Inst) || MIA->isUnconditionalBranch(Inst) || MIA->isConditionalBranch(Inst)`
which is used to guard `MCInstrAnalysis::evaluateBranch()`

Reviewed By: jhenderson, skan

Differential Revision: https://reviews.llvm.org/D78776
2020-04-27 09:43:51 -07:00
Mark Murray 3df8135286 [ARM][MC][Thumb] Recommit: Revert relocation for some pc-relative fixups.
Summary:
This commit recommits the reversion of https://reviews.llvm.org/D75039.

Concensus appears to be in favour of assembly-time resolution of
these ADR and LDR relocations, in line with GNU. The previous
backout broke many lld tests, now fixed by Peter Smith in
61bccda9d9.

Reviewers: psmith

Subscribers: kristof.beyls, hiraditya, danielkiss, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78301
2020-04-22 16:54:26 +01:00
Shengchen Kan c031378ce0 [MC][NFC] Use camelCase style for functions in MCObjectStreamer 2020-04-20 20:09:20 -07:00
Shengchen Kan 8bb059ab63 [MC][Bugfix] Remove redundant parameter for relaxInstruction
Summary:
Before this patch, `relaxInstruction` takes three arguments, the first
argument refers to the instruction before relaxation and the third
argument is the output instruction after relaxation. There are two quite
strange things:
  1) The first argument's type is `const MCInst &`, the third
  argument's type is `MCInst &`, but they may be aliased to the same
  variable
  2) The backends of ARM, AMDGPU, RISC-V, Hexagon assume that the third
  argument is a fresh uninitialized `MCInst` even if `relaxInstruction`
  may be called like `relaxInstruction(Relaxed, STI, Relaxed)` in a
  loop.

In this patch, we drop the thrid argument, and let `relaxInstruction`
directly modify the given instruction. Also, this patch fixes the bug https://bugs.llvm.org/show_bug.cgi?id=45580, which is introduced by D77851, and
breaks the assumption of ARM, AMDGPU, RISC-V, Hexagon.

Reviewers: Razer6, MaskRay, jyknight, asb, luismarques, enderby, rtaylor, colinl, bcain

Reviewed By: Razer6, MaskRay, bcain

Subscribers: bcain, nickdesaulniers, nathanchance, wuzish, annita.zhang, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, tpr, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78364
2020-04-21 11:06:55 +08:00
Mark Murray f5a812cbcc Revert 3ce0ad1b33 Die to breakage in check-lld.
Requested-by: Nico Weber
2020-04-20 13:01:36 +01:00
Mark Murray 3ce0ad1b33 [ARM][MC][Thumb] Revert relocation for some pc-relative fixups.
Summary:
This commit reverts https://reviews.llvm.org/D75039. Concensus appears to
be in favour of assembly-time resolution of these ADR and LDR relocations,
in line with GNU.

Reviewers: psmith

Subscribers: kristof.beyls, hiraditya, danielkiss, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78301
2020-04-20 09:38:12 +01:00
Fangrui Song 7d1ff446b6 [MC] Rename MCSection*::getSectionName() to getName(). NFC
A pending change will merge MCSection*::getName() to MCSection::getName().
2020-04-15 16:48:14 -07:00
Sam Parker dd8153b757 [ARM][MVE] Tail predicate VML[A|S]LDAV
Make the non-exchanging versions of the multiply add/sub instructions
validForTailPredication.

Differential Revision: https://reviews.llvm.org/D77648
2020-04-15 11:34:39 +01:00
Peter Smith 31c8e11896 [MC][ARM] Emit R_ARM_BASE_PREL for _GLOBAL_OFFSET_TABLE_ expressions
The _GLOBAL_OFFSET_TABLE_ in SysVr4 ELF is conventionally the base of the
.got or .got.prel sections. Expressions such as _GLOBAL_OFFSET_TABLE_
- (.L1 +8) are used in assembler code to calculate offsets into the .got.
At present MC outputs a R_ARM_REL32 with respect to the
_GLOBAL_OFFSET_TABLE_ symbol, whereas gas outputs a R_ARM_BASE_PREL
relocation with respect to the _GLOBAL_OFFSET_TABLE_ symbol. While both are
correct the R_ARM_REL32 depends on the value of the _GLOBAL_OFFSET_TABLE_
symbol, wheras te R_ARM_BASE_PREL relocation is idependent of the symbol.
The R_ARM_BASE_PREL is therefore slightly more robust to linker's that may
not follow the conventional placement of _GLOBAL_OFFSET_TABLE_; for example
LLD for some time defined _GLOBAL_OFFSET_TABLE_ to 0.

Differential Revision: https://reviews.llvm.org/D46319
2020-04-14 10:13:21 +01:00
Fangrui Song 0a55d3f557 [MC] Default MCAsmInfo::UseIntegratedAssembler to true 2020-04-11 10:13:52 -07:00
Kai Wang 581ba35291 [RISCV] ELF attribute section for RISC-V.
Leverage ARM ELF build attribute section to create ELF attribute section
for RISC-V. Extract the common part of parsing logic for this section
into ELFAttributeParser.[cpp|h] and ELFAttributes.[cpp|h].

Differential Revision: https://reviews.llvm.org/D74023
2020-03-31 16:16:19 +08:00
Fangrui Song c389526171 [MC][ARM] Make .reloc support arbitrary relocation types
Generalizes D61992. In GNU as, the .reloc directive supports arbitrary relocation types.

A MCFixupKind value `V` larger than or equal to FirstLiteralRelocationKind
is used to represent the relocation type whose number is V-FirstLiteralRelocationKind.

This is useful for linker tests. Without the feature the assembler
cannot produce certain relocation records (e.g.  R_ARM_ALU_PC_G0/R_ARM_LDR_PC_G0)
This helps move forward D75349 and D76575.

Differential Revision: https://reviews.llvm.org/D76746
2020-03-27 12:29:49 -07:00
Sam Parker 0e6aa08381 [ARM][MVE] Add DoubleWidthResult flag
Add a flag for those instructions which read from the top/bottom
halves of their inputs and produce a vector of results with double
width elements.

Differential Revision: https://reviews.llvm.org/D76762
2020-03-27 13:44:04 +00:00
Fangrui Song 6728a9ae19 [MCInstPrinter] Add parameter `Address` to printCustomAliasOperand. NFC
Follow-up of D72172 and llvmorg-11-init-6896-gb3cc5dcef0f.
2020-03-27 00:38:20 -07:00
Fangrui Song b3cc5dcef0 [MCInstPrinter] Add parameter `Address` to MCInstPrinter::printAliasInstr. NFC
Follow-up of D72172.
2020-03-27 00:03:32 -07:00
Fangrui Song 5fad05e80d [MCInstPrinter] Pass `Address` parameter to MCOI::OPERAND_PCREL typed operands. NFC
Follow-up of D72172 and D72180

This patch passes `uint64_t Address` to print methods of PC-relative
operands so that subsequent target specific patches can change
`*InstPrinter::print{Operand,PCRelImm,...}` to customize the output.

Add MCInstPrinter::PrintBranchImmAsAddress which is set to true by
llvm-objdump.

```
// Current llvm-objdump -d output
aarch64: 20000: bl #0
ppc:     20000: bl .+4
x86:     20000: callq 0

// Ideal output
aarch64: 20000: bl 0x20000
ppc:     20000: bl 0x20004
x86:     20000: callq 0x20005

// GNU objdump -d. The lack of 0x is not ideal because the result cannot be re-assembled
aarch64: 20000: bl 20000
ppc:     20000: bl 0x20004
x86:     20000: callq 20005
```

In `lib/Target/X86/X86GenAsmWriter1.inc` (generated by `llvm-tblgen -gen-asm-writer`):

```
   case 12:
     // CALL64pcrel32, CALLpcrel16, CALLpcrel32, EH_SjLj_Setup, JCXZ, JECXZ, J...
-    printPCRelImm(MI, 0, O);
+    printPCRelImm(MI, Address, 0, O);
     return;
```

Some targets have 2 `printOperand` overloads, one without `Address` and
one with `Address`. They should annotate derived `Operand` properly with
`let OperandType = "OPERAND_PCREL"`.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D76574
2020-03-26 08:21:15 -07:00
Ties Stuij 71ae267d1f [PATCH] [ARM] ARMv8.6-a command-line + BFloat16 Asm Support
Summary:
This patch introduces command-line support for the Armv8.6-a architecture and assembly support for BFloat16. Details can be found
https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/arm-architecture-developments-armv8-6-a

in addition to the GCC patch for the 8..6-a CLI:
https://gcc.gnu.org/legacy-ml/gcc-patches/2019-11/msg02647.html

In detail this patch

- march options for armv8.6-a
- BFloat16 assembly

This is part of a patch series, starting with command-line and Bfloat16
assembly support. The subsequent patches will upstream intrinsics
support for BFloat16, followed by Matrix Multiplication and the
remaining Virtualization features of the armv8.6-a architecture.

Based on work by:
- labrinea
- MarkMurrayARM
- Luke Cheeseman
- Javed Asbar
- Mikhail Maltsev
- Luke Geeson

Reviewers: SjoerdMeijer, craig.topper, rjmccall, jfb, LukeGeeson

Reviewed By: SjoerdMeijer

Subscribers: stuij, kristof.beyls, hiraditya, dexonsmith, danielkiss, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D76062
2020-03-26 09:17:20 +00:00
Sam Parker e87250202d [ARM][MVE] Add HorizontalReduction flag
Add a target flag for instructions that reduce into one, or more,
scalar reg(s), including variants of:
- VADDV
- VABAV
- VMINV/VMAXV
- VMLADAV

Differential Revision: https://reviews.llvm.org/D76683
2020-03-25 11:12:03 +00:00
Sam Parker 6f86e6bf40 [ARM][MVE] Add target flag for narrowing insts
Add a flag, 'RetainsPreviousHalfElement', for operations that operate
on top/bottom halves of their input and only write to half of their
destination, leaving the other half to retain its previous value.

Differential Revision: https://reviews.llvm.org/D76608
2020-03-24 08:36:44 +00:00
Fangrui Song 692e0c9648 [MC] Add MCStreamer::emitInt{8,16,32,64}
Similar to AsmPrinter::emitInt{8,16,32,64}.
2020-02-29 09:40:21 -08:00
Peter Smith 2a92fc9b8e [MC][ELF][ARM] Add relocations for some pc-relative fixups
Add ELF relocations for the following fixups:
fixup_thumb_adr_pcrel_10 -> R_ARM_THM_PC8
fixup_thumb_cp -> R_ARM_THM_PC8
fixup_t2_adr_pcrel_12 -> R_ARM_THM_PREL_11_0
fixup_t2_ldst_pcrel_12 -> R_ARM_THM_PC12

While these relocations are short-ranged there is support in the open
source ELF linker's in binutils and soon to be in LLD. MC will no longer
resolve pc-relative fixups to global symbols due to interpositioning
concerns. We can handle these at link time by implementing the relocations.

The R_ARM_THM_PC8 has some extra encoding rules for addends that llvm-mc
sidesteps by not supporting addends for these instructions, using the wide
Thumb 2 instruction if it is available. I think that this is a reasonable
compromise given that these are rare.

This partiall reverts D72892, the Thumb fixups no longer need to be
evaluated at assembly time.

Differential Revision: https://reviews.llvm.org/D75039
2020-02-28 11:29:29 +00:00
Hans Wennborg 2e24219d3c [MC][ARM] Resolve some pcrel fixups at assembly time (PR44929)
MC currently does not emit these relocation types, and lld does not
handle them. Add FKF_Constant as a work-around of some ARM code after
D72197. Eventually we probably should implement these relocation types.

By Fangrui Song!

Differential revision: https://reviews.llvm.org/D72892
2020-02-27 12:43:29 +01:00
Fangrui Song d0c4277d38 [MC][ARM] Don't create multiple .ARM.exidx associated to one .text
Fixed an issue exposed by D74006.

In clang cc1as, MCContext::UseNamesOnTempLabels is true.
When parsing a .fnstart directive, FnStart gets redefined to a temporary symbol of a different name (.Ltmp0, .Ltmp1, ...).
MCContext::getELFSection() called by SwitchToEHSection() will create a different .ARM.exidx each time.

llvm-mc uses `Ctx.setUseNamesOnTempLabels(false);` and FnStart is unnamed.
MCContext::getELFSection() called by SwitchToEHSection() will reuse the same .ARM.exidx .

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D75095
2020-02-25 18:18:13 -08:00