Remove lazy-initialization of section caches in MCContext

This seems to have been a cargo-culted habit from the very first such
cache which didn't have any specific justification (but might've been

Remove lazy-initialization of section caches in MCContext

This seems to have been a cargo-culted habit from the very first such
cache which didn't have any specific justification (but might've been a
layering constraint at the time).

llvm-svn: 206003

show more ...

Reimplement debug info compression by compressing the whole section, rather than a fragment.

To support compressing the debug_line section that contains multiple
fragments (due, I believe, to variat

Reimplement debug info compression by compressing the whole section, rather than a fragment.

To support compressing the debug_line section that contains multiple
fragments (due, I believe, to variation in choices of line table
encoding depending on the size of instruction ranges in the actual
program code) we needed to support compressing multiple MCFragments in a
single pass.

This patch implements that behavior by mutating the post-relaxed and
relocated section to be the compressed form of its former self,
including renaming the section.

This is a more flexible (and less invasive, to a degree) implementation
that will allow for other features such as "use compression only if it's
smaller than the uncompressed data".

Compressing debug_frame would be a possible further extension to this
work, but I've left it for now. The hurdle there is alignment sections -
which might require going as far as to refactor
MCAssembler.cpp:writeFragment to handle writing to a byte buffer or an
MCObjectWriter (there's already a virtual call there, so it shouldn't
add substantial compile-time cost) which could in turn involve
refactoring MCAsmBackend::writeNopData to use that same abstraction...
which involves touching all the backends. This would remove the limited
handling of fragment writing seen in
ELFObjectWriter.cpp:getUncompressedData which would be nice - but it's
more invasive.

I did discover that I (perhaps obviously) don't need to handle
relocations when I rewrite the fragments - since the relocations have
already been applied and computed (and stored into
ELFObjectWriter::Relocations) by this stage (necessarily, because we
need to have written any immediate values or assembly-time relocations
into the data already before we compress it, which we have). The test
case doesn't necessarily cover that in detail - I can add more test
coverage if that's preferred.

llvm-svn: 205990

show more ...

Revert debug info compression support.

To support compression for debug_line and debug_frame a different
approach is required. To simplify review, revert the old implementation
and XFAIL the test ca

Revert debug info compression support.

To support compression for debug_line and debug_frame a different
approach is required. To simplify review, revert the old implementation
and XFAIL the test case. New implementation to follow shortly.

Reverts r205059 and r204958.

llvm-svn: 205989

show more ...

MachO: allow each section to have a linker-private symbol

The upcoming ARM64 backend doesn't have section-relative relocations,
so we give each section its own symbol to provide this functionality.

MachO: allow each section to have a linker-private symbol

The upcoming ARM64 backend doesn't have section-relative relocations,
so we give each section its own symbol to provide this functionality.
Of course, it doesn't need to appear in the final executable, so
linker-private is the best kind for this purpose.

llvm-svn: 205081

show more ...

Debug Compression: Avoid compression debug_frame for now

Turns out debug_frame does use multiple fragments, so it doesn't
compress correctly with the current approach. Disable compressing it for
now

Debug Compression: Avoid compression debug_frame for now

Turns out debug_frame does use multiple fragments, so it doesn't
compress correctly with the current approach. Disable compressing it for
now while I figure out what's the best solution for it.

llvm-svn: 205059

show more ...

DebugInfo: Support for compressed debug info sections

1) When creating a .debug_* section and instead create a .zdebug_
section.
2) When creating a fragment in a .zdebug_* section, make it a comp

DebugInfo: Support for compressed debug info sections

1) When creating a .debug_* section and instead create a .zdebug_
section.
2) When creating a fragment in a .zdebug_* section, make it a compressed
fragment.
3) When computing the size of a compressed section, compress the data
and use the size of the compressed data.
4) Emit the compressed bytes.

Also, check that only if a section has a compressed fragment, then that
is the only fragment in the section.

Assert-fail if the fragment's data is modified after it is compressed.

Initial review on llvm-commits by Eric Christopher and Rafael Espindola.

llvm-svn: 204958

show more ...

MC: don't create a backtrace for diagnostics.

For better or worse, this is currently the normal error reporting path
when dealing with backend errors from inline assembly. It's not just
internal com

MC: don't create a backtrace for diagnostics.

For better or worse, this is currently the normal error reporting path
when dealing with backend errors from inline assembly. It's not just
internal compiler issues that come through here, so we shouldn't be
creating a backtrace on this path.

rdar://16329947

llvm-svn: 203979

show more ...

MCContext: Remove redundant assignment

The member variable is not initialized in the ctor so it's already
empty. No need to empty it again.

llvm-svn: 203963

MCDwarf: Rename MCDwarfFileTable to MCDwarfLineTable

This type now represents all the data for the DWARF line table:
directory names, file names, and the line table proper.

llvm-svn: 203858

MCDwarf: Sink file/directory creation down into MCDwarfFileTable form MCContext

llvm-svn: 203836

MCDwarf: Oh, and move the directory string over to std::string as well

(see r203831 for similar stuff)

llvm-svn: 203833

MCDwarf: Simplify MCDwarfFile to just use std::string instead of cunning use of MCContext's allocator.

There aren't /that/ many files, and we are already using various maps
and other standard contai

MCDwarf: Simplify MCDwarfFile to just use std::string instead of cunning use of MCContext's allocator.

There aren't /that/ many files, and we are already using various maps
and other standard containers that don't use MCContext's allocator to
store these values, so this doesn't seem to be critical and simplifies
the design (I'll be moving construction out of MCContext shortly so it'd
be annoying to have to pass the allocator around to allocate these
things... and we'll have non-MCContext users (debug_line.dwo) shortly)

llvm-svn: 203831

show more ...

MCDwarf: Simply MCDwarfFile since it really is just a StringRef and unsigned.

llvm-svn: 203827

Use printable names to implement directional labels.

This changes the implementation of local directional labels to use a dedicated
map. With that it can then just use CreateTempSymbol, which is wha

Use printable names to implement directional labels.

This changes the implementation of local directional labels to use a dedicated
map. With that it can then just use CreateTempSymbol, which is what the rest
of MC uses.

CreateTempSymbol doesn't do a great job at making sure the names are unique
(or being efficient when the names are not needed), but that should probably
be fixed in a followup patch.

This fixes pr18928.

llvm-svn: 203826

show more ...

Remove stale comment

llvm-svn: 203823

MCDwarf: Refactor line table handling into a single data structure

This replaces several "compile unit ID -> thing" mappings in favor of
one mapping from CUID to the whole line table structure (file

MCDwarf: Refactor line table handling into a single data structure

This replaces several "compile unit ID -> thing" mappings in favor of
one mapping from CUID to the whole line table structure (files,
directories, and lines).

This is another step along the way to refactoring out reusable
components of line table handling for use when generating debug_line.dwo
for fission type units.

Also, might be a good basis to fold some of this handling down into
MCStreamers to avoid the special case of "One line table when doing asm
printing, line table per CU otherwise" by building it into the different
MCStreamer implementations.

llvm-svn: 203821

show more ...

MCDwarf: Invert the Section+CU->LineEntries mapping so the CU is the primary dimension

This makes the mapping consistent with other CU->X mappings in the
MCContext, helping pave the way to refactor

MCDwarf: Invert the Section+CU->LineEntries mapping so the CU is the primary dimension

This makes the mapping consistent with other CU->X mappings in the
MCContext, helping pave the way to refactor all these values into a
single data structure per CU and thus a single map.

I haven't renamed the data structure as that would make the patch churn
even higher (the MCLineSection name no longer makes sense, as this
structure now contains lines for multiple sections covered by a single
CU, rather than lines for a single section in multiple CUs) and further
refactorings will follow that may remove this type entirely.

For convenience, I also gave the MCLineSection value semantics so we
didn't have to do the lazy construction, manual delete, etc.

(& for those playing at home, refactoring the line printing into a
single data structure will eventually alow that data structure to be
reused to own the debug_line.dwo line table used for type unit file name
resolution)

llvm-svn: 203726

show more ...

Correct typo ("a entry" -> "an entry")

llvm-svn: 203678

Re-sort all of the includes with ./utils/sort_includes.py so that
subsequent changes are easier to review. About to fix some layering
issues, and wanted to separate out the necessary churn.

Also com

Re-sort all of the includes with ./utils/sort_includes.py so that
subsequent changes are easier to review. About to fix some layering
issues, and wanted to separate out the necessary churn.

Also comment and sink the include of "Windows.h" in three .inc files to
match the usage in Memory.inc.

llvm-svn: 198685

show more ...

Fix a crash that occurs when PWD is invalid.

MCJIT needs to be able to run in hostile environments, even when PWD
is invalid. There's no need to crash MCJIT in this case.

The obvious fix is to simp

Fix a crash that occurs when PWD is invalid.

MCJIT needs to be able to run in hostile environments, even when PWD
is invalid. There's no need to crash MCJIT in this case.

The obvious fix is to simply leave MCContext's CompilationDir empty
when PWD can't be determined. This way, MCJIT clients,
and other clients that link with LLVM don’t need a valid working directory.

If we do want to guarantee valid CompilationDir, that should be done
only for clients of getCompilationDir(). This is as simple as checking
for an empty string.

The only current use of getCompilationDir is EmitGenDwarfInfo, which
won’t conceivably run with an invalid working dir. However, in the
purely hypothetically and untestable case that this happens, the
AT_comp_dir will be omitted from the compilation_unit DIE.

llvm-svn: 196874

show more ...

whitespace

llvm-svn: 196873

Correct word hyphenations

This patch tries to avoid unrelated changes other than fixing a few
hyphen-related ambiguities and contractions in nearby lines.

llvm-svn: 196471

Avoid buffer copies when a Twine already is a StringRef.

llvm-svn: 196301

Support multiple COFF sections with the same name but different COMDAT.

This is the first step to fix pr17918.

It extends the .section directive a bit, inspired by what the ELF one looks
like. The

Support multiple COFF sections with the same name but different COMDAT.

This is the first step to fix pr17918.

It extends the .section directive a bit, inspired by what the ELF one looks
like. The problem with using linkonce is that given

.section foo
.linkonce....

.section foo
.linkonce

we would already have switched sections when getting to .linkonce. The cleanest
solution seems to be to add the comdat information in the .section itself.

llvm-svn: 195148

show more ...

MC: Support multiple sections with the same name in the same comdat group

Code review by Eric Christopher and Rafael Espindola.

llvm-svn: 193209