CodeView, like most other debug formats, represents the live range of a
variable so that debuggers might print them out.
They use a variety of records to represent how a particular variable
might be available (in a register, in a frame pointer, etc.) along with
a set of ranges where this debug information is relevant.
However, the format only allows us to use ranges which are limited to a
maximum of 0xF000 in size. This means that we need to split our debug
information into chunks of 0xF000.
Because the layout of code is not known until *very* late, we must use a
new fragment to record the information we need until we can know
*exactly* what the range is.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259868 91177308-0d34-0410-b5e6-96231b3b80d8
CodeView requires us to accurately describe the extent of the inlined
code. We did this by grabbing the next debug location in source order
and using *that* to denote where we stopped inlining. However, this is
not sufficient or correct in instances where there is no next debug
location or the next debug location belongs to the start of another
function.
To get this correct, use the end symbol of the function to denote the
last possible place the inlining could have stopped at.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259548 91177308-0d34-0410-b5e6-96231b3b80d8
This directive emits the binary annotations that describe line and code
deltas in inlined call sites. Single-stepping through inlined frames in
windbg now works.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259535 91177308-0d34-0410-b5e6-96231b3b80d8
This support is _very_ rudimentary, just enough to get some basic data
into the CodeView debug section.
Left to do is:
- Use the combined opcodes to save space.
- Do something about code offsets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259230 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r259117.
The LineInfo constructor is defined in the codeview library and we have
to link against it now. Doing that isn't trivial, so reverting for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259126 91177308-0d34-0410-b5e6-96231b3b80d8
Adds a new family of .cv_* directives to LLVM's variant of GAS syntax:
- .cv_file: Similar to DWARF .file directives
- .cv_loc: Similar to the DWARF .loc directive, but starts with a
function id. CodeView line tables are emitted by function instead of
by compilation unit, so we needed an extra field to communicate this.
Rather than overloading the .loc direction further, we decided it was
better to have our own directive.
- .cv_stringtable: Emits the codeview string table at the current
position. Currently this just contains the filenames as
null-terminated strings.
- .cv_filechecksums: Emits the file checksum table for all files used
with .cv_file so far. There is currently no support for emitting
actual checksums, just filenames.
This moves the line table emission code down into the assembler. This
is in preparation for implementing the inlined call site line table
format. The inline line table format encoding algorithm requires knowing
the absolute code offsets, so it must run after the assembler has laid
out the code.
David Majnemer collaborated on this patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259117 91177308-0d34-0410-b5e6-96231b3b80d8
The value size was always 1 or 0, so we don't need to store it.
In a no asserts build this takes the testcase of pr26208 from 11 to 10
seconds.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258141 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Support for R_MIPS_NONE allows us to parse MIPS16's usage of .reloc.
R_MIPS_32 was included to be able to better test the directive.
Targets can add their relocations by overriding MCAsmBackend::getFixupKind().
Subscribers: grosbach, rafael, majnemer, dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D13659
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252888 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249303 91177308-0d34-0410-b5e6-96231b3b80d8
We can just ask the ObjectWriter for it's stream instead of caching
around our own reference to it. No functionality change is intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246604 91177308-0d34-0410-b5e6-96231b3b80d8
After r244870 flush() will only compare two null pointers and return,
doing nothing but wasting run time. The call is not required any more
as the stream and its SmallString are always in sync.
Thanks to David Blaikie for reviewing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244928 91177308-0d34-0410-b5e6-96231b3b80d8
NFC patch for current users, but llvm-dsymutil will use the new
functionality to adapt to the input linetable.
Based on a patch by Adrian Prantl.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244318 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The current implementation doesn't always flush all pending labels
beforeemitting data which can result in an incorrectly placed labels in
case when when instruction bundling is enabled and -mc-relax-all flag is
being used. To address this issue, we always flush pending labels before
emitting data.
The change was tested by running PNaCl toolchain trybots with
-mc-relax-all flag set.
Fixes https://code.google.com/p/nativeclient/issues/detail?id=4063
Test Plan: Regression test attached
Reviewers: mseaborn
Subscribers: jfb, llvm-commits
Differential Revision: http://reviews.llvm.org/D10325
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240870 91177308-0d34-0410-b5e6-96231b3b80d8
This makes emitAbsoluteSymbolDiff always succeed and moves logic from the asm
printer to it.
The object one now also works on ELF. If two symbols are in the same fragment,
we will never move them apart.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239552 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238708 91177308-0d34-0410-b5e6-96231b3b80d8
Both MCStreamer and MCObjectStreamer were maintaining a current section
variable and they were slightly out of sync. I don't think this was observable,
but was inefficient and error prone.
Changing this requires a few cascading changes:
* SwitchSection has to call ChangeSection earlier for ChangeSection to see
the old section.
* With that change, ChangeSection cannot call EmitLabel, since during
ChangeSection we are still in the old section.
* When the object streamer requires a begin label, just reused the existing
generic support for begin labels instead of calling EmitLabel directly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238357 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
Create a low-overhead path for `EmitLabelDifference()` that emits a
emits an absolute number when (1) the output is an object stream and (2)
the two symbols are in the same data fragment.
This drops memory usage on Mach-O from 975 MB down to 919 MB (5.8%).
The only call is when `!doesDwarfUseRelocationsAcrossSections()` --
i.e., on Mach-O -- since otherwise an absolute offset from the start of
the section needs a relocation. (`EmitLabelDifference()` is cheaper on
ELF anyway, since it creates 1 fewer temp symbol, and it gets called far
less often. It's not clear to me if this is even a bottleneck there.)
(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@237876 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When instruction bundling is enabled and the -mc-relax-all flag is
set, we can write bundle padding directly into fragments and avoid
creating large number of fragments significantly reducing LLVM MC
memory usage.
Test Plan: Regression test attached
Reviewers: eliben
Subscribers: jfb, mseaborn
Differential Revision: http://reviews.llvm.org/D8072
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234714 91177308-0d34-0410-b5e6-96231b3b80d8
