In MCObjectStreamer, when there is no current fragment, initially
symbols are created in a "pending" state and assigned to a dummy
empty fragment.
Previously, they were not being assigned an offset, and thus
evaluateAbsolute would fail if trying to evaluate an expression 'a -
b', where both 'a' and 'b' were in this pending state.
Also slightly refactored the EmitLabel overload which takes an
MCFragment for clarity.
Fixes: https://llvm.org/PR41825
Differential Revision: https://reviews.llvm.org/D70062
This patch emits the function descriptor csect for functions with definitions
under both 32-bit/64-bit mode on AIX.
Differential Revision: https://reviews.llvm.org/D66724
llvm-svn: 373009
D18885 emitted 5 bytes for call *foo@tlsdesc(%rax). It should use the
2-byte form instead and let R_X86_64_TLSDESC_CALL apply to the beginning
of the call instruction.
The 2-byte form was deliberately chosen to make ->LE and ->IE relaxation work:
0: 48 8d 05 00 00 00 00 lea 0x0(%rip),%rax # 7 <.text+0x7>
3: R_X86_64_GOTPC32_TLSDESC a-0x4
7: ff 10 callq *(%rax)
7: R_X86_64_TLSDESC_CALL a
=>
0: 48 c7 c0 fc ff ff ff mov $0xfffffffffffffffc,%rax
7: 66 90 xchg %ax,%ax
Also change the symbol type to STT_TLS when VK_TLSCALL or VK_TLSDESC is
seen.
Reviewed By: compnerd
Differential Revision: https://reviews.llvm.org/D62512
llvm-svn: 361910
N_FUNC_COLD is a new MachO symbol attribute. It's a hint to the linker
to order a symbol towards the end of its section, to improve locality.
Example:
```
void a1() {}
__attribute__((cold)) void a2() {}
void a3() {}
int main() {
a1();
a2();
a3();
return 0;
}
```
A linker that supports N_FUNC_COLD will order _a2 to the end of the text
section. From `nm -njU` output, we see:
```
_a1
_a3
_main
_a2
```
Differential Revision: https://reviews.llvm.org/D57190
llvm-svn: 352227
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
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
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
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
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
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 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
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
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
With this we only create an alias for @@@ once we know if it should
use @ or @@. This avoids last minutes renames and hacks to handle MS
names.
This only handles the ELF writer. LTO still has issues with @@@
aliases.
llvm-svn: 327160
This patch starts simplifying the handling of .symver.
For now it just moves the responsibility for creating an alias down to
the streamer. With that the asm streamer can pass a .symver unchanged,
which is nice since gas cannot parse "foo@bar = zed".
In a followup I hope to move the handling down to the writer so that
we don't need special hacks for avoiding breaking names with @@@ on
windows.
llvm-svn: 327101
MCObjectStreamer owns its MCCodeEmitter -- this fixes the types to reflect that,
and allows us to remove the last instance of MCObjectStreamer's weird "holding
ownership via someone else's reference" trick.
llvm-svn: 315531
MCObjectStreamer owns its MCAsmBackend -- this fixes the types to reflect that,
and allows us to remove another instance of MCObjectStreamer's weird "holding
ownership via someone else's reference" trick.
llvm-svn: 315410
functions.
This makes the ownership of the resulting MCObjectWriter clear, and allows us
to remove one instance of MCObjectStreamer's bizarre "holding ownership via
someone else's reference" trick.
llvm-svn: 315327
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
Dont emit Mapping symbols for sections that contain only data.
Summary:
Dont emit mapping symbols for sections that contain only data.
Reviewers: rengolin, weimingz, kparzysz, t.p.northover, peter.smith
Reviewed By: t.p.northover
Patched by Shankar Easwaran <shankare@codeaurora.org>
Subscribers: alekseyshl, t.p.northover, llvm-commits
Differential Revision: https://reviews.llvm.org/D30724
llvm-svn: 299392
Instead of requiring every non-COFF MCObjectStreamer to implement the
COFF hooks just to do an llvm_unreachable to say that they're not
supported, do the llvm_unreachable in the default implementation, as
suggested by rnk in https://reviews.llvm.org/D26722.
llvm-svn: 296403
This makes sure we get the same redefinition rules regardless of who
is printing (asm parser, codegen) and to what (asm, obj).
This fixes an unintentional regression in r293936.
llvm-svn: 294752
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
Move the cast<MCSymbolELF> inside emitELFSize, so that:
- it's done in one place instead of at each call
- it's more consistent with similar functions like EmitCOFFSafeSEH
- ambiguity between cast<> and dyn_cast<> is avoided (which also
eliminates an unnecessary dyn_cast call)
This also makes it easier to experiment with using ".size" directives on
non-ELF targets.
llvm-svn: 288437
Summary:
This is much closer to the way MIPS relocation expressions work
(%hi(foo + 2) rather than %hi(foo) + 2) and removes the need for the
various bodges in MipsAsmParser::evaluateRelocExpr().
Removing those bodges ensures that the constant stored in MCValue is the
full 32 or 64-bit (depending on ABI) offset from the symbol. This will be used
to correct the %hi/%lo matching needed to sort the relocation table correctly.
As part of this:
* Gave MCExpr::print() the ability to omit parenthesis when emitting a
symbol reference inside a MipsMCExpr operator like %hi(X). Without this
we print things like %lo(($L1)).
* %hi(%neg(%gprel(X))) is now three MipsMCExpr's instead of one. Most of
the related special cases have been removed or moved to MipsMCExpr. We
can remove the rest as we gain support for the less common relocations
when they are not part of this specific combination.
* Renamed MipsMCExpr::VariantKind and the enum prefix ('VK_') to avoid confusion
with MCSymbolRefExpr::VariantKind and its prefix (also 'VK_').
* fixup_Mips_GOT_Local and fixup_Mips_GOT_Global were found to be identical
and merged into fixup_Mips_GOT.
* MO_GOT16 and MO_GOT turned out to be identical and have been merged into
MO_GOT.
* VK_Mips_GOT and VK_Mips_GOT16 turned out to be the same thing so they
have been merged into MEK_GOT
Reviewers: sdardis
Subscribers: dsanders, sdardis, llvm-commits
Differential Revision: http://reviews.llvm.org/D19716
llvm-svn: 268379
This patch adds support for the MachO .alt_entry assembly directive, and uses
it for global aliases with non-zero GEP offsets. The alt_entry flag indicates
that a symbol should be layed out immediately after the preceding symbol.
Conceptually it introduces an alternate entry point for a function or data
structure. E.g.:
safe_foo:
// check preconditions for foo
.alt_entry fast_foo
fast_foo:
// body of foo, can assume preconditions.
The .alt_entry flag is also implicitly set on assembly aliases of the form:
a = b + C
where C is a non-zero constant, since these have the same effect as an
alt_entry symbol: they introduce a label that cannot be moved relative to the
preceding one. Setting the alt_entry flag on aliases of this form fixes
http://llvm.org/PR25381.
llvm-svn: 263521
This extends the work done in r233995 so that now getFragment (in addition to
getSection) also works for variable symbols.
With that the existing logic to decide if a-b can be computed works even if
a or b are variables. Given that, the expression evaluation can avoid expanding
variables as aggressively and that in turn lets the relocation code see the
original variable.
In order for this to work with the asm streamer, there is now a dummy fragment
per section. It is used to assign a section to a symbol when no other fragment
exists.
This patch is a joint work by Maxim Ostapenko andy myself.
llvm-svn: 249303
Fangrui Song