We can probably take this a step further since the only
user of the isUsed flag is AsmParser it should probably
be doing this explicitly. For now this is a step in the
right direction though.
Differential Revision: https://reviews.llvm.org/D41971
llvm-svn: 322386
This just adds the basic skeleton for supporting a new object file format.
All of the actual encoding will be implemented in followup patches.
Differential Revision: https://reviews.llvm.org/D26722
llvm-svn: 295803
MCSymbol.h shouldn't pull in MCAssembler.h, just MCFragment.h.
MCLinkerOptimizationHint.h shouldn't need MCMachObjectWriter.h. The
rest is fixing the fallout.
llvm-svn: 273507
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
Avoid marking some MCSymbols as used in MC/AsmParser.cpp when no uses
exist. This fixes a bug in parseAssignmentExpression() which
inadvertently sets IsUsed, thereby triggering:
"invalid re-assignment of non-absolute variable"
on otherwise valid code. No other functionality change intended.
The original version of this patch touched many calls to MCSymbol
accessors. On rafael's advice, I have stripped this patch down a bit.
As a follow-up, I intend to find the call sites which intentionally set
IsUsed and force them to do so explicitly.
Differential Revision: http://reviews.llvm.org/D12347
llvm-svn: 246457
All file formats only needed 16-bits right now which is enough to fit
in to the padding with other fields.
This reduces the size of MCSymbol to 24-bytes on a 64-bit system. The
layout is now
0 | class llvm::MCSymbol
0 | class llvm::PointerIntPair SectionOrFragmentAndHasName
0 | intptr_t Value
| [sizeof=8, dsize=8, align=8
| nvsize=8, nvalign=8]
8 | unsigned int IsTemporary
8 | unsigned int IsRedefinable
8 | unsigned int IsUsed
8 | _Bool IsRegistered
8 | unsigned int IsExternal
8 | unsigned int IsPrivateExtern
8 | unsigned int Kind
9 | unsigned int IsUsedInReloc
9 | unsigned int SymbolContents
9 | unsigned int CommonAlignLog2
10 | uint32_t Flags
12 | uint32_t Index
16 | union
16 | uint64_t Offset
16 | uint64_t CommonSize
16 | const class llvm::MCExpr * Value
| [sizeof=8, dsize=8, align=8
| nvsize=8, nvalign=8]
| [sizeof=24, dsize=24, align=8
| nvsize=24, nvalign=8]
llvm-svn: 241196
Given that alignments are always powers of 2, just encode it this way.
This matches how we encode alignment on IR GlobalValue's for example.
This compresses the CommonAlign member down to 5 bits which allows it
to pack better with the surrounding fields.
Reviewed by Duncan Exon Smith.
llvm-svn: 241189
This is part of an effort to pack the average MCSymbol down to 24 bytes.
The HasName bit was pushing the size of the bitfield over to another word,
so this change uses a PointerIntPair to fit in it to unused bits of a
PointerUnion.
Reviewed by Rafael Espíndola
llvm-svn: 241115
This is a reapplication of r239440 which was reverted in r239441.
There are no changes to this patch from then, but this had instead exposed
a bug in .thumb_set which was fixed in r240318. Having fixed that bug, it
is now safe to re-apply this code.
Original commit message below:
It wasn't possible to have a variable Symbol with offset or 'isCommon' so
this just enables better packing of the MCSymbol class.
Reviewed by Rafael Espindola.
llvm-svn: 240320
This reverts commit 2e449ec5bcdf67b52b315b16c2128aaf25d5b73c.
This was svn r239440. Its currently failing an ARM test so reverting while I work out
what to do next.
llvm-svn: 239441
It wasn't possible to have a variable Symbol with offset or 'isCommon' so
this just enables better packing of the MCSymbol class.
Reviewed by Rafael Espindola.
llvm-svn: 239440
Based on feedback to r239428 by David Blaikie, use const_cast to reduce
duplication of the const and non-const versions of getNameEntryPtr.
Also have that method return the pointer to the name directly instead
of users having to then get the name from the union.
Finally, add a FIXME that we should use a static_assert once available in
the new operator.
llvm-svn: 239429
This should hopefully fix the 32-bit bots which were allocating space for a pointer
but needed to be aligned to 64-bits.
Now we allocate enough space for a uint64_t and a pointer and cast to the appropriate storage
llvm-svn: 239428
Similarly to User which allocates a number of Use's prior to the this pointer,
allocate space for the Name* for MCSymbol only when we need a name.
Given that an MCSymbol is 48-bytes on 64-bit systems, this saves a decent % of space.
Given the verify_uselistorder test case with debug info and llc, 50k symbols have names
out of 700k so this optimises for the common case of temporary unnamed symbols.
Reviewed by David Blaikie.
llvm-svn: 239423
Fixes most of the test suite on Windows with clang-cl.
I'm not sure why the test suite was passing with MSVC 2013. Maybe they
changed their behavior and we are emulating their old sign extension
behavior. I think this deserves more investigation, but I want to green
the bot first.
llvm-svn: 239357
All of ELF, COFF and MachO now manipulate the flags in helpers so we don't need
anyone to read the flags directly, but instead via those helpers.
Reviewed by Rafael Espíndola.
llvm-svn: 239317
This create a MCSymbolELF class and moves SymbolSize since only ELF
needs a size expression.
This reduces the size of MCSymbol from 56 to 48 bytes.
llvm-svn: 238801
There is no MCSectionData, so the old name is now meaningless.
Also remove some asserts/checks that were there just because the information
they used was in MCSectionData.
llvm-svn: 238708
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.)
llvm-svn: 238005
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.)
llvm-svn: 238003
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.
llvm-svn: 237936
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.)
llvm-svn: 237873
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.
llvm-svn: 237868
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.)
llvm-svn: 237490
