On darwin, all virtual sections have zerofill type, and having a
.zerofill directive in a non-virtual section is not allowed. Instead of
asserting, show a nicer error.
In order to use the equivalent of .zerofill in a non-virtual section,
the usage of .zero of .space is required.
This patch replaces the assert with an error.
Differential Revision: https://reviews.llvm.org/D48517
llvm-svn: 336127
section flags in the ELF assembler. This matches the defaults
given in the rest of MC.
Fixes PR37997 where we couldn't assemble our own assembly output
without warnings.
llvm-svn: 336072
There are quite a few if statements that enumerate all these cases. It gets
even worse in our fork of LLVM where we also have a Triple::cheri (which
is mips64 + CHERI instructions) and we had to update all if statements that
check for Triple::mips64 to also handle Triple::cheri. This patch helps to
reduce our diff to upstream and should also make some checks more readable.
Reviewed By: atanasyan
Differential Revision: https://reviews.llvm.org/D48548
llvm-svn: 335493
DWARF v5 explicitly represents file #0 in the line table. Prior
versions did not, so ".loc 0" is still an error in those cases.
Differential Revision: https://reviews.llvm.org/D48452
llvm-svn: 335350
With compilation fix.
Original commit message:
D39788 added a '.stack-size' section containing metadata on function stack sizes
to output ELF files behind the new -stack-size-section flag.
This change does following two things on top:
1) Imagine the case when there are -ffunction-sections flag given and there are text sections in COMDATs.
The patch adds a '.stack-size' section into corresponding COMDAT group, so that linker will be able to
eliminate them fast during resolving the COMDATs.
2) Patch sets a SHF_LINK_ORDER flag and links '.stack-size' with the corresponding .text.
With that linker will be able to do -gc-sections on dead stack sizes sections.
Differential revision: https://reviews.llvm.org/D46874
llvm-svn: 335336
D39788 added a '.stack-size' section containing metadata on function stack sizes
to output ELF files behind the new -stack-size-section flag.
This change does following two things on top:
1) Imagine the case when there are -ffunction-sections flag given and there are text sections in COMDATs.
The patch adds a '.stack-size' section into corresponding COMDAT group, so that linker will be able to
eliminate them fast during resolving the COMDATs.
2) Patch sets a SHF_LINK_ORDER flag and links '.stack-size' with the corresponding .text.
With that linker will be able to do -gc-sections on dead stack sizes sections.
Differential revision: https://reviews.llvm.org/D46874
llvm-svn: 335332
Summary:
GCC and the binutils COFF linker do comdats differently from MSVC.
If we want to be ABI compatible, we have to do what they do, which is to
emit unique section names like ".text$_Z3foov" instead of short section
names like ".text". Otherwise, the binutils linker gets confused and
reports multiple definition errors when two object files from GCC and
Clang containing the same inline function are linked together.
The best description of the issue is probably at
https://github.com/Alexpux/MINGW-packages/issues/1677, we don't seem to
have a good one in our tracker.
I fixed up the .pdata and .xdata sections needed everywhere other than
32-bit x86. GCC doesn't use associative comdats for those, it appears to
rely on the section name.
Reviewers: smeenai, compnerd, mstorsjo, martell, mati865
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D48402
llvm-svn: 335286
This patch teaches llvm-mca how to identify register writes that implicitly zero
the upper portion of a super-register.
On X86-64, a general purpose register is implemented in hardware as a 64-bit
register. Quoting the Intel 64 Software Developer's Manual: "an update to the
lower 32 bits of a 64 bit integer register is architecturally defined to zero
extend the upper 32 bits". Also, a write to an XMM register performed by an AVX
instruction implicitly zeroes the upper 128 bits of the aliasing YMM register.
This patch adds a new method named clearsSuperRegisters to the MCInstrAnalysis
interface to help identify instructions that implicitly clear the upper portion
of a super-register. The rest of the patch teaches llvm-mca how to use that new
method to obtain the information, and update the register dependencies
accordingly.
I compared the kernels from tests clear-super-register-1.s and
clear-super-register-2.s against the output from perf on btver2. Previously
there was a large discrepancy between the estimated IPC and the measured IPC.
Now the differences are mostly in the noise.
Differential Revision: https://reviews.llvm.org/D48225
llvm-svn: 335113
Enables using the high and high-adjusted symbol modifiers on thread local
storage modifers in powerpc assembly. Needed to be able to support 64 bit
thread-pointer and dynamic-thread-pointer access sequences.
Differential Revision: https://reviews.llvm.org/D47754
llvm-svn: 334856
Add support for the "@high" and "@higha" symbol modifiers in powerpc64 assembly.
The modifiers represent accessing the segment consiting of bits 16-31 of a
64-bit address/offset.
Differential Revision: https://reviews.llvm.org/D47729
llvm-svn: 334855
Instruction bundling is only supported on descendants of the
MCEncodedFragment type. By moving the bundling functionality and
MCSubtargetInfo to this class it makes it easier to set and extract the
MCSubtargetInfo when it is necessary.
This is a refactoring change that will make it easier to pass the
MCSubtargetInfo through to writeNops when nop padding is required.
Differential Revision: https://reviews.llvm.org/D45959
llvm-svn: 334814
This reverts rL331412. We didn't up using fragment atoms
in the wasm object writer after all.
Differential Revision: https://reviews.llvm.org/D48173
llvm-svn: 334734
In some cases, for example when compiling a preprocessed file, the
front-end is not able to provide an MD5 checksum for all files. When
that happens, omit the MD5 checksums from the final DWARF, because
DWARF doesn't have a way to indicate that some but not all files have
a checksum.
When assembling a .s file, and some but not all .file directives
provide an MD5 checksum, issue a warning and don't emit MD5 into the
DWARF.
Fixes PR37623.
Differential Revision: https://reviews.llvm.org/D48135
llvm-svn: 334710
Don't provide the assembler source as the "root file" unless the user
asked to have debug info for the assembler source (with -g).
If the source doesn't provide an explicit ".file 0" then (a) use the
compilation directory as directory #0, and (b) use the file #1 info
for file #0 also.
Differential Revision: https://reviews.llvm.org/D48055
llvm-svn: 334512
On targets like Arm some relaxations may only be performed when certain
architectural features are available. As functions can be compiled with
differing levels of architectural support we must make a judgement on
whether we can relax based on the MCSubtargetInfo for the function. This
change passes through the MCSubtargetInfo for the function to
fixupNeedsRelaxation so that the decision on whether to relax can be made
per function. In this patch, only the ARM backend makes use of this
information. We must also pass the MCSubtargetInfo to applyFixup because
some fixups skip error checking on the assumption that relaxation has
occurred, to prevent code-generation errors applyFixup must see the same
MCSubtargetInfo as fixupNeedsRelaxation.
Differential Revision: https://reviews.llvm.org/D44928
llvm-svn: 334078
This is a fix for the problem arising in D47374 (PR37678):
https://bugs.llvm.org/show_bug.cgi?id=37678
We may not have throughput info because it's not specified in the model
or it's not available with variant scheduling, so assume that those
instructions can execute/complete at max-issue-width.
Differential Revision: https://reviews.llvm.org/D47723
llvm-svn: 334055
Summary:
Allow extended parsing of variable assembler assignment syntax and modify X86 to permit
VAR = register assignment. As we emit these as .set directives when possible, we inline
such expressions in output assembly.
Fixes PR37425.
Reviewers: rnk, void, echristo
Reviewed By: rnk
Subscribers: nickdesaulniers, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D47545
llvm-svn: 334022
Object FIle Representation
At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like:
.cg_profile a, b, 32
.cg_profile freq, a, 11
.cg_profile freq, b, 20
When writing an ELF file these are put into a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight).
Differential Revision: https://reviews.llvm.org/D44965
llvm-svn: 333823
This patch extends the MCSchedModel API with new methods that can be used to
obtain the latency and reciprocal througput information for an MCInst.
Scheduling models have recently gained the ability to resolve variant scheduling
classes associated with MCInst objects. Before, models were only able to resolve
a variant scheduling class from a MachineInstr object.
This patch is mainly required by D47374 to avoid regressing a pair of x86
specific -print-schedule tests for btver2. Patch D47374 introduces a new variant
class to teach the btver scheduling model (x86 target) how to correctly compute
the latency profile for some zero-idioms using the new scheduling predicates.
The new methods added by this patch would be mainly used by llc when flag
-print-schedule is specified. In particular, tests that contain inline assembly
require that code is parsed at code emission stage into a sequence of MCInst.
That forces the print-schedule functionality to query the latency/rthroughput
information for MCInst instructions too. If we don't expose this new API, then
we lose "-print-schedule" test coverage as soon as variant scheduling classes
are added to the x86 models.
The tablegen SubtargetEmitter changes teaches how to query latency profile
information using a object that derives from TargetSubtargetInfo. Note that this
should really have been part of r333286. To avoid code duplication, the logic
that "resolves" variant scheduling classes for MCInst, has been moved to a
common place in MC. That logic is used by the "resolveVariantSchedClass" methods
redefined in override by the tablegen'd GenSubtargetInfo classes.
Differential Revision: https://reviews.llvm.org/D47536
llvm-svn: 333650
For RISC-V it is desirable to have relaxation happen in the linker once
addresses are known, and as such the size between two instructions/byte
sequences in a section could change.
For most assembler expressions, this is fine, as the absolute address results
in the expression being converted to a fixup, and finally relocations.
However, for expressions such as .quad .L2-.L1, the assembler folds this down
to a constant once fragments are laid out, under the assumption that the
difference can no longer change, although in the case of linker relaxation the
differences can change at link time, so the constant is incorrect. One place
where this commonly appears is in debug information, where the size of a
function expression is in a form similar to the above.
This patch extends the assembler to allow an AsmBackend to declare that it
does not want the assembler to fold down this expression, and instead generate
a pair of relocations that allow the linker to carry out the calculation. In
this case, the expression is not folded, but when it comes to emitting a
fixup, the generic FK_Data_* fixups are converted into a pair, one for the
addition half, one for the subtraction, and this is passed to the relocation
generating methods as usual. I have named these FK_Data_Add_* and
FK_Data_Sub_* to indicate which half these are for.
For RISC-V, which supports this via e.g. the R_RISCV_ADD64, R_RISCV_SUB64 pair
of relocations, these are also set to always emit relocations relative to
local symbols rather than section offsets. This is to deal with the fact that
if relocations were calculated on e.g. .text+8 and .text+4, the result 12
would be stored rather than 4 as both addends are added in the linker.
Differential Revision: https://reviews.llvm.org/D45181
Patch by Simon Cook.
llvm-svn: 333079
This code appears to have been copied from the mach-o streamer. It has
no effect in ELF because indirect symbols are specific to mach-o.
llvm-svn: 332926
This class will be used to create regular, non-split ELF files.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47049
llvm-svn: 332870
With this we gain a little flexibility in how the generic object
writer is created.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47045
llvm-svn: 332868
Also clean up a couple of hacks where we were writing the section
contents to another stream by setting the object writer's stream,
writing and setting it back.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47038
llvm-svn: 332858
To make this work I needed to add an endianness field to MCAsmBackend
so that writeNopData() implementations know which endianness to use.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47035
llvm-svn: 332857
Provide some free functions to reduce verbosity of endian-writing
a single value, and replace the endianness template parameter with
a field.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47032
llvm-svn: 332757
The idea is that a client that wants split dwarf would create a
specific kind of object writer that creates two files, and use it to
create the streamer.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47050
llvm-svn: 332749
Avoid requirement that number of values must be known at assembler
time.
Fixes PR33586.
Reviewers: rnk, peter.smith, echristo, jyknight
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D46703
llvm-svn: 332741
For RISCV branch instructions, we need to preserve relocation types when linker
relaxation enabled, so then linker could modify offset when the branch offsets
changed.
We preserve relocation types by define shouldForceRelocation.
IsResolved return by evaluateFixup will always false when shouldForceRelocation
return true. It will make RISCV MC Branch Relaxation always relax 16-bit
branches to 32-bit form, even if the symbol actually could be resolved.
To avoid 16-bit branches always relax to 32-bit form when linker relaxation
enabled, we add a new parameter WasForced to indicate that the symbol actually
couldn't be resolved and not forced by shouldForceRelocation return true.
RISCVAsmBackend::fixupNeedsRelaxationAdvanced could relax branches with
unresolved symbols by (!IsResolved && !WasForced).
RISCV MC Branch Relaxation is needed because RISCV could perform 32-bit
to 16-bit transformation in MC layer.
Differential Revision: https://reviews.llvm.org/D46350
llvm-svn: 332696
The getAtom() method wasn't doing what we needed in all cases. We want
the symbols for the function which defines that section. We can compute
this easily enough and we know that we have at most one function in each
section.
Once this lands I will revert rL331412 which is no longer needed.
Fixes PR37409
Differential Revision: https://reviews.llvm.org/D46970
llvm-svn: 332517
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
llvm-svn: 332240
