Shave a pointer off of `MCSymbolName` by storing `StringMapEntry<bool>*`
instead of `StringRef`. This brings `sizeof(MCSymbol)` down to 64 on
64-bit platforms, a nice round number. My profile showed memory
dropping from 914 MB down to 908 MB, roughly 0.7%. Other than memory
usage, no functionality change here.
(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238005 91177308-0d34-0410-b5e6-96231b3b80d8
Save a pointer for each `MCSymbol`, bringing `llc` memory usage down
from 920 MB to 914 MB, around ~0.6%.
(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238003 91177308-0d34-0410-b5e6-96231b3b80d8
Lift `MCSymbolData::Index` up a level to `MCSymbol`, as preparation for
packing it into the bitfield in `MCSymbol`.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238001 91177308-0d34-0410-b5e6-96231b3b80d8
This starts merging MCSection and MCSectionData.
There are a few issues with the current split between MCSection and
MCSectionData.
* It optimizes the the not as important case. We want the production
of .o files to be really fast, but the split puts the information used
for .o emission in a separate data structure.
* The ELF/COFF/MachO hierarchy is not represented in MCSectionData,
leading to some ad-hoc ways to represent the various flags.
* It makes it harder to remember where each item is.
The attached patch starts merging the two by moving the alignment from
MCSectionData to MCSection.
Most of the patch is actually just dropping 'const', since
MCSectionData is mutable, but MCSection was not.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237936 91177308-0d34-0410-b5e6-96231b3b80d8
Try to fix miscompile after r237873. Looks like this union
initialization isn't legal (or at least not supported).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237875 91177308-0d34-0410-b5e6-96231b3b80d8
Finally remove the `MCSymbolData::Symbol` pointer. It was still being
used to track whether `MCSymbolData` had been initialized, but this is
better tracked by the bitfield in `MCSymbol`.
The only caller of `MCSymbolData::initialize()` was `MCAssembler`, which
(other than `Symbol`) passed in all-0 values. Replace all that
indirection with a default constructor.
The main point is a cleanup (and there's more cleanup to do), but there
are also some small memory savings. I measured ~989 MB down to ~975 MB,
cutting a little over 1% off the top of `llc`.
(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237873 91177308-0d34-0410-b5e6-96231b3b80d8
Make the back-pointer from `MCSymbolData` to `MCSymbol` private,
preparing to remove the back pointer entirely. I've already updated all
the users, although for now it's still used to indicate whether
`MCSymbol::Data` has been initialized.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237868 91177308-0d34-0410-b5e6-96231b3b80d8
Turn `MCSymbolData` into a field inside of `MCSymbol`. Keep all the old
API alive for now, so that consumers can be updated in a later commit.
This means we still temporarily need the back pointer from
`MCSymbolData` to `MCSymbol`, but I'll remove it in a follow-up.
This optimizes for object emission over assembly emission. By removing
the `DenseMap` in `MCAssembler`, llc memory usage drops from around 1040
MB to 1001 MB (3.8%).
(I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`;
see r236629 for details.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237490 91177308-0d34-0410-b5e6-96231b3b80d8
Currently symbol names are printed in quotes if it contains something
outside of the arbitrary set of characters that isAcceptableChar tests
for. On somem targets, it is never OK to print a symbol name in quotes
so allow targets to opt out of this behavior.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235670 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes PR19582.
Previously, when an asm assignment (.set or =) was created, we would look up
the section immediately in MCSymbol::setVariableValue. This caused symbols
to receive the wrong section if the RHS of the assignment had not been seen
yet. This had a knock-on effect in the object file emitters, causing them
to emit extra symbols, or to give symbols the wrong visibility or the wrong
section. For example, in the following asm:
.data
.Llocal:
.text
leaq .Llocal1(%rip), %rdi
.Llocal1 = .Llocal2
.Llocal2 = .Llocal
the first assignment would give .Llocal1 a null section, which would never get
fixed up by the second assignment. This would cause the ELF object file emitter
to consider .Llocal1 to be an undefined symbol and give it external linkage,
even though .Llocal1 should not have been emitted at all in the object file.
Or in the following asm:
alias_to_local = Ltmp0
Ltmp0:
the Mach-O object file emitter would give the alias_to_local symbol a n_type
of N_SECT and a n_sect of 0. This is invalid under the Mach-O specification,
which requires N_SECT symbols to receive a non-zero section number if the
symbol is defined in a section in the object file.
https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/MachORuntime/#//apple_ref/c/tag/nlist
After this change we do not look up the section when the assignment is created,
but instead look it up on demand and store it in Section, which is treated
as a cache if the symbol is a variable symbol.
This change also fixes a bug in MCExpr::FindAssociatedSection. Previously,
if we saw a subtraction, we would return the first referenced section, even in
cases where we should have been returning the absolute pseudo-section. Now we
always return the absolute pseudo-section for expressions that subtract two
section-derived expressions. This isn't always correct (e.g. if one of the
sections ends up being laid out at an absolute address), but it's probably
the best we can do without more context.
This allows us to remove code in two places where we appear to have been
working around this bug, in MachObjectWriter::markAbsoluteVariableSymbols
and in X86AsmPrinter::EmitStartOfAsmFile.
Re-applies r233595 (aka D8586), which was reverted in r233898.
Differential Revision: http://reviews.llvm.org/D8798
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233995 91177308-0d34-0410-b5e6-96231b3b80d8
.set directives may be overridden by other .set directives as well as
label definitions.
This fixes PR22019.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224811 91177308-0d34-0410-b5e6-96231b3b80d8
The revision I'm reverting breaks handling of transitive aliases. This blocks us
and breaks sanitizer bootstrap:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/2651
(and checked locally by Alexey).
This revision is the result of:
svn merge -r204059:204058 -r204028:204027 -r203962:203961 .
+ the regression test added to test/MC/ELF/alias.s
Another way to reproduce the regression with clang:
$ cat q.c
void a1();
void a2() __attribute__((alias("a1")));
void a3() __attribute__((alias("a2")));
void a1() {}
$ ~/work/llvm-build/bin/clang-3.5-good -c q.c && mv q.o good.o && \
~/work/llvm-build/bin/clang-3.5-bad -c q.c && mv q.o bad.o && \
objdump -t good.o bad.o
good.o: file format elf64-x86-64
SYMBOL TABLE:
0000000000000000 l df *ABS* 0000000000000000 q.c
0000000000000000 l d .text 0000000000000000 .text
0000000000000000 l d .data 0000000000000000 .data
0000000000000000 l d .bss 0000000000000000 .bss
0000000000000000 l d .comment 0000000000000000 .comment
0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack
0000000000000000 l d .eh_frame 0000000000000000 .eh_frame
0000000000000000 g F .text 0000000000000006 a1
0000000000000000 g F .text 0000000000000006 a2
0000000000000000 g F .text 0000000000000006 a3
bad.o: file format elf64-x86-64
SYMBOL TABLE:
0000000000000000 l df *ABS* 0000000000000000 q.c
0000000000000000 l d .text 0000000000000000 .text
0000000000000000 l d .data 0000000000000000 .data
0000000000000000 l d .bss 0000000000000000 .bss
0000000000000000 l d .comment 0000000000000000 .comment
0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack
0000000000000000 l d .eh_frame 0000000000000000 .eh_frame
0000000000000000 g F .text 0000000000000006 a1
0000000000000000 g F .text 0000000000000006 a2
0000000000000000 g .text 0000000000000000 a3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204137 91177308-0d34-0410-b5e6-96231b3b80d8
We were marking the symbol as absolute instead of computing b's offset + the
expression value.
This fixes pr19126.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203962 91177308-0d34-0410-b5e6-96231b3b80d8
This patch tries to avoid unrelated changes other than fixing a few
hyphen-related ambiguities and contractions in nearby lines.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196471 91177308-0d34-0410-b5e6-96231b3b80d8
* wrap code blocks in \code ... \endcode;
* refer to parameter names in paragraphs correctly (\arg is not what most
people want -- it starts a new paragraph);
* use \param instead of \arg to document parameters in order to be consistent
with the rest of the codebase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163902 91177308-0d34-0410-b5e6-96231b3b80d8
variable if recursing fails to simplify it.
Factor AliasedSymbol to be a method of MCSymbol.
Update MCAssembler::EvaluateFixup to match the change in
EvaluateAsRelocatableImpl.
Remove the WeakRefExpr hack, as the object writer now sees the weakref with
no extra effort needed.
Nothing else is using MCTargetExpr, but keep it for now.
Now that the ELF writer sees relocations with aliases, handle
.weak foo2
foo2:
.weak bar2
.set bar2,foo2
.quad bar2
the same way gas does and produce a relocation with bar2.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119152 91177308-0d34-0410-b5e6-96231b3b80d8
This moves most of the isUsed logic to the MCSymbol itself. With this we
get a bit more relaxed about allowing definitions after uses: uses that
don't evaluate their argument immediately (jmp foo) are accepted.
ddunbar, this was the smallest compromise I could think of that lets us
accept gcc (and clang!) assembly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119144 91177308-0d34-0410-b5e6-96231b3b80d8
variable has not yet been used in an expression. This allows us to support a few
cases that show up in real code (mostly because gcc generates it for Objective-C
on Darwin), without giving up a reasonable semantic model for assignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103950 91177308-0d34-0410-b5e6-96231b3b80d8
allocated and thus not freed. This is cool except that it contains
and std::string so the string data didn't get freed. In any case
there is no reason to redundantly store the string data in the
MCSymbol anyway, just make the MCSymbol ref the string data in the
MCContext StringMap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98536 91177308-0d34-0410-b5e6-96231b3b80d8
remove it and change all the code that prints MCSymbols to use
<< instead, which is much simpler and cleaner.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93695 91177308-0d34-0410-b5e6-96231b3b80d8
to Mangler. Now MCSymbol just decides whether to slap quotes around
a symbol when printing it.
This also fixes some weirdness where two MCSymbols could be created
for the same symbol, if one needed to be mangled and got mangled to
the other one.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93690 91177308-0d34-0410-b5e6-96231b3b80d8
and fix a few things using << on MCSymbols to use ->print(). No
functionality change other than unbreaking my previous patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80890 91177308-0d34-0410-b5e6-96231b3b80d8
- I moved section creation back into AsmParser. I think policy decisions like
this should be pushed higher, not lower, when possible (in addition the
assembler has flags which change this behavior, for example).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80162 91177308-0d34-0410-b5e6-96231b3b80d8
- Honor .globl.
- Set symbol type and section correctly ('nm' now works), and order symbols
appropriately.
- Take care to the string table so that the .o matches 'as' exactly (for ease
of testing).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79740 91177308-0d34-0410-b5e6-96231b3b80d8
(external was really undefined and there wasn't an explicit representation for
absolute symbols).
- This still needs some cleanup to how the absolute "pseudo" section is dealt
with, but I haven't figured out the nicest approach yet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79733 91177308-0d34-0410-b5e6-96231b3b80d8
doing it directly. This requires const'izing a bunch of stuff that
took sections, but this seems like the right semantic thing to do:
emitting a label to a section shouldn't mutate the MCSection object
itself, for example.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79227 91177308-0d34-0410-b5e6-96231b3b80d8
