This patch provides a means to specify section-names for global variables,
functions and static variables, using #pragma directives.
This feature is only defined to work sensibly for ELF targets.
One can specify section names as:
#pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
One can "unspecify" a section name with empty string e.g.
#pragma clang section bss="" data="" text="" rodata=""
Reviewers: Roger Ferrer, Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D33413
llvm-svn: 304704
This is motivated by https://reviews.llvm.org/D32488 where I am trying
to add printing of the section type for incompatible sections to LLD
error messages. This patch allows us to use the same code in
llvm-readobj and LLD instead of duplicating the function inside LLD.
Patch by Alexander Richardson!
llvm-svn: 301921
Set correct default flags and section type based on its name for .text,
.data, .bss, .init_array, .fini_array, .preinit_array, .tdata, and .tbss
and support section name suffixes for .data.*, .rodata.*, .text.*,
.bss.*, .tdata.* and .tbss.* which matches the behavior of GAS.
Fixes PR31888.
Differential Revision: https://reviews.llvm.org/D30229
llvm-svn: 299484
Make MCSectionELF::AssociatedSection be a link to a symbol, because
that's how it works in the assembly, and use it in the asm printer.
llvm-svn: 297769
GAS supports specification of section header's type using a numeric
value [1]. This patch brings the same functionality to LLVM. That allows
to setup some target-specific section types belong to the SHT_LOPROC -
SHT_HIPROC range. If we attempt to print unknown section type, MCSectionELF
class shows an error message. It's better than print sole '@' sign
without any section type name.
In case of MIPS, example of such section's type is SHT_MIPS_DWARF.
Without the patch we will have to implement some workarounds
in probably not-MIPS-specific part of code base to convert SHT_MIPS_DWARF
to the @progbits while printing assembly and to assign SHT_MIPS_DWARF for
@progbits sections named .debug_* if we encounter such section in
an input assembly.
[1] https://sourceware.org/binutils/docs/as/Section.html
Differential Revision: https://reviews.llvm.org/D29719
llvm-svn: 297446
This is for running the assembler with -g (to emit DWARF describing
the assembler source).
Differential Revision: http://reviews.llvm.org/D30475
llvm-svn: 296541
On ELF every section can have a corresponding section symbol. When in
an assembly file we have
.quad .text
the '.text' refers to that symbol.
The way we used to handle them is to leave .text an undefined symbol
until the very end when the object writer would map them to the
actual section symbol.
The problem with that is that anything before the end would see an
undefined symbol. This could result in bad diagnostics
(test/MC/AArch64/label-arithmetic-diags-elf.s), or incorrect results
when using the asm streamer (est/MC/Mips/expansion-jal-sym-pic.s).
Fixing this will also allow using the section symbol earlier for
setting sh_link of SHF_METADATA sections.
This patch includes a few hacks to avoid changing our behaviour when
handling conflicts between section symbols and other symbols. I
reported pr31850 to track that.
llvm-svn: 293936
One more attempt to re-commit the patch r285355, which I had to revert in r285362, because some tests were failing (the reason is because the size of the line_table varied depending on the full file name).
In the past the compiler always emitted .debug_line version 2, though some opcodes from DWARF 3 (e.g. DW_LNS_set_prologue_end, DW_LNS_set_epilogue_begin or DW_LNS_set_isa) and from DWARF 4 could be emitted by the compiler.
This patch changes version information of .debug_line to exactly match the DWARF version. For .debug_line version 4, a new field maximum_operations_per_instruction is emitted.
Differential Revision: https://reviews.llvm.org/D16697
llvm-svn: 289925
Summary:
GAS already allows flags for sections to be specified directly as a
numeric value. This functionality is particularly useful for setting
processor or application-specific values that may not be directly
supported or understood by LLVM. This patch allows LLVM to use numeric
section flag values verbatim if specified by the assembly file.
Reviewers: grosbach, rafael, t.p.northover, rengolin
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27451
llvm-svn: 289785
This implements execute-only support for ARM code generation, which
prevents the compiler from generating data accesses to code sections.
The following changes are involved:
* Add the CodeGen option "-arm-execute-only" to the ARM code generator.
* Add the clang flag "-mexecute-only" as well as the GCC-compatible
alias "-mpure-code" to enable this option.
* When enabled, literal pools are replaced with MOVW/MOVT instructions,
with VMOV used in addition for floating-point literals. As the MOVT
instruction is required, execute-only support is only available in
Thumb mode for targets supporting ARMv8-M baseline or Thumb2.
* Jump tables are placed in data sections when in execute-only mode.
* The execute-only text section is assigned section ID 0, and is
marked as unreadable with the SHF_ARM_PURECODE flag with symbol 'y'.
This also overrides selection of ELF sections for globals.
llvm-svn: 289784
In the past the compiler always emitted .debug_line version 2, though some opcodes from DWARF 3 (e.g. DW_LNS_set_prologue_end, DW_LNS_set_epilogue_begin or DW_LNS_set_isa) and from DWARF 4 could be emitted by the compiler.
This patch changes version information of .debug_line to exactly match the DWARF version. For .debug_line version 4, a new field maximum_operations_per_instruction is emitted.
Differential Revision: https://reviews.llvm.org/D16697
llvm-svn: 285355
llvm-mc is a developer tool, as such it make sense for it to use new
features by default.
This doesn't change the user facing clang, which still defaults to non
relaxable relocations.
llvm-svn: 273014
We were producing R_X86_64_GOTPCRELX for invalid instructions and
sometimes producing R_X86_64_GOTPCRELX instead of
R_X86_64_REX_GOTPCRELX.
llvm-svn: 271118
It was: "Recommit 270977 - [llvm-mc] - Teach llvm-mc to generate zlib styled compression sections."
Fix:
since test requires no zlib available and r270987 changed the
compression flag for llvm-mc to mandatory specify the compression style,
then just add 2 available styles to this test.
llvm-svn: 270992
Fix: updated clang code which was not updated by mistake.
Original commit message:
[llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.
This patch is strongly based on previously reverted D20331.
(because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style)
Difference that this patch supports both zlib and zlib-gnu styles.
-compress-debug-sections option now supports next values:
-compress-debug-sections=zlib-gnu
-compress-debug-sections=zlib
-compress-debug-sections=none
Previously specifying -compress-debug-sections enabled zlib-gnu compression,
so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior
that was before this patch for case when compression was enabled.
Differential revision: http://reviews.llvm.org/D20676
llvm-svn: 270987
It broke buildbot:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/13585/steps/build/logs/stdio
Initial commit message:
[llvm-mc] - Teach llvm-mc to generate zlib styled compression sections.
This patch is strongly based on previously reverted D20331.
(because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style)
Difference that this patch supports both zlib and zlib-gnu styles.
-compress-debug-sections option now supports next values:
-compress-debug-sections=zlib-gnu
-compress-debug-sections=zlib
-compress-debug-sections=none
Previously specifying -compress-debug-sections enabled zlib-gnu compression,
so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior
that was before this patch for case when compression was enabled.
Differential revision: http://reviews.llvm.org/D20676
llvm-svn: 270978
This patch is strongly based on previously reverted D20331.
(because of gnuutils < 2.26 does not support compressed debug sections in non zlib-gnu style)
Difference that this patch supports both zlib and zlib-gnu styles.
-compress-debug-sections option now supports next values:
-compress-debug-sections=zlib-gnu
-compress-debug-sections=zlib
-compress-debug-sections=none
Previously specifying -compress-debug-sections enabled zlib-gnu compression,
so anyone can put "-compress-debug-sections=zlib-gnu" to restore the behavior
that was before this patch for case when compression was enabled.
Differential revision: http://reviews.llvm.org/D20676
llvm-svn: 270977
Now, after landing r270560, r270557, r270320 it is a proper time.
Original commit message:
[llvm-mc] - Teach llvm-mc to generate compressed debug sections in zlib style.
Before this patch llvm-mc generated zlib-gnu styled sections.
That means no SHF_COMPRESSED flag was set, magic 'zlib' signature
was used in combination with full size field. Sections were renamed to "*.z*".
This patch reimplements the compression style to zlib one as zlib-gnu looks
to be depricated everywhere.
Differential revision: http://reviews.llvm.org/D20331
llvm-svn: 270569
Main problem that .debug_info
section was used to check that llvm-dwarfdump is able to decompress
data that was compressed with llvm-mc tool. This section was not compressed
actually, because consumes more space in compressed view.
I changed testcase to use .debug_str section which is one that
is really compressed. So currently test do what is probably was expected to do:
checks that "data"->llvm-mc->llvm-dwarfdump->dumps back initial "data".
Differential revision: http://reviews.llvm.org/D20466
llvm-svn: 270560
It broke buildbot:
http://lab.llvm.org:8011/builders/clang-s390x-linux/builds/4817/steps/ninja%20check%201/logs/stdio
Actually it is just because D20273 not yet commited, but these 2 were crossing with each other,
and I`ll better find the way to land them separatelly soon.
Initial commit message:
[llvm-mc] - Teach llvm-mc to generate compressed debug sections in zlib style.
Before this patch llvm-mc generated zlib-gnu styled sections.
That means no SHF_COMPRESSED flag was set, magic 'zlib' signature
was used in combination with full size field. Sections were renamed to "*.z*".
This patch reimplements the compression style to zlib one as zlib-gnu looks
to be depricated everywhere.
Differential revision: http://reviews.llvm.org/D20331
llvm-svn: 270075
Before this patch llvm-mc generated zlib-gnu styled sections.
That means no SHF_COMPRESSED flag was set, magic 'zlib' signature
was used in combination with full size field. Sections were renamed to "*.z*".
This patch reimplements the compression style to zlib one as zlib-gnu looks
to be depricated everywhere.
Differential revision: http://reviews.llvm.org/D20331
llvm-svn: 270070
The option to control the emission of the new relocations
is -relax-relocations (blatantly copied from GNU as).
It can't be enabled by default because it breaks relatively
recent versions of ld.bfd/ld.gold (late 2015).
llvm-svn: 267307
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.
Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.
Motivation
----------
Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.
We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.
Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.
http://reviews.llvm.org/D19034
<rdar://problem/25256815>
llvm-svn: 266446
Since we can't emit diagnostics for missing "jmp 1f" labels until the end of
the file, we need to be able to restore the context used to calculate
file/line. This is basically the "# line file" directive that's being used at
the time the expression is seen.
rdar://25706972
llvm-svn: 266238
Before, ELF at least managed a diagnostic but it was a completely untraceable
"undefined symbol" error. MachO had a variety of even worse behaviours: crash,
emit corrupt file, or an equally bad message.
llvm-svn: 265984
This is a fix for PR26941.
When there is both a section and a global definition with the same
name, the global wins.
Section symbols are not added to the symbol table; section references
are left undefined and fixed up in the object writer unless they've
been satisfied by some other definition.
llvm-svn: 264649
Adding support for section names with special characters in them (e.g. "/").
GCC successfully compiles such section names.
This also fixes PR24520.
Differential Revision: http://reviews.llvm.org/D15678
llvm-svn: 264038
When a symbol S shows up in an expression in assembly there are two
possible interpretations
* The expression is referring to the value of S in this file.
* The expression is referring to the value after symbol resolution.
In the first case the assembler can reason about the value and try to
produce a relocation.
In the second case, that is only possible if the symbol cannot be
preempted.
Assemblers are not very consistent about which interpretation gets used.
This changes MC to agree with GAS in the case of an expression of the
form "Sym - WeakSym".
llvm-svn: 258329
InitMCObjectFileInfo was trying to override the triple in awkward ways.
For example, a triple specifying COFF but not Windows was forced as ELF.
This makes it easy for internal invariants to get violated, such as
those which triggered PR25912.
This fixes PR25912.
llvm-svn: 256226
Prior to this patch, we would wrongly stick to the variant with imm8 encoding
even when the relocation could not fit that size.
rdar://problem/23785506
llvm-svn: 255583
Rafael Espindola