Commit Graph

16415 Commits

Author SHA1 Message Date
Nuno Lopes
2ca626570f remove a bunch of unused private methods
found with a smarter version of -Wunused-member-function that I'm playwing with.
Appologies in advance if I removed someone's WIP code.

 include/llvm/CodeGen/MachineSSAUpdater.h            |    1 
 include/llvm/IR/DebugInfo.h                         |    3 
 lib/CodeGen/MachineSSAUpdater.cpp                   |   10 --
 lib/CodeGen/PostRASchedulerList.cpp                 |    1 
 lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp    |   10 --
 lib/IR/DebugInfo.cpp                                |   12 --
 lib/MC/MCAsmStreamer.cpp                            |    2 
 lib/Support/YAMLParser.cpp                          |   39 ---------
 lib/TableGen/TGParser.cpp                           |   16 ---
 lib/TableGen/TGParser.h                             |    1 
 lib/Target/AArch64/AArch64TargetTransformInfo.cpp   |    9 --
 lib/Target/ARM/ARMCodeEmitter.cpp                   |   12 --
 lib/Target/ARM/ARMFastISel.cpp                      |   84 --------------------
 lib/Target/Mips/MipsCodeEmitter.cpp                 |   11 --
 lib/Target/Mips/MipsConstantIslandPass.cpp          |   12 --
 lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp              |   21 -----
 lib/Target/NVPTX/NVPTXISelDAGToDAG.h                |    2 
 lib/Target/PowerPC/PPCFastISel.cpp                  |    1 
 lib/Transforms/Instrumentation/AddressSanitizer.cpp |    2 
 lib/Transforms/Instrumentation/BoundsChecking.cpp   |    2 
 lib/Transforms/Instrumentation/MemorySanitizer.cpp  |    1 
 lib/Transforms/Scalar/LoopIdiomRecognize.cpp        |    8 -
 lib/Transforms/Scalar/SCCP.cpp                      |    1 
 utils/TableGen/CodeEmitterGen.cpp                   |    2 
 24 files changed, 2 insertions(+), 261 deletions(-)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204560 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-23 17:09:26 +00:00
Andrea Di Biagio
d47cb57ab8 [DAG] Fix an assertion failure caused by an invalid cast in method 'BuildVectorSDNode::isConstantSplat'
This patch renames method 'isConstantSplat' as 'getConstantSplatValue'
(mainly for consistency reasons), and rewrites its logic to ensure
that we always perform a legal 'cast<ConstantSDNode>'.

Added test shift-combine-crash.ll to verify that DAGCombiner no longer crashes with an assertion failure in the attempt to simplify a vector shift by a vector of all undef counts.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204536 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-22 01:47:22 +00:00
Adrian Prantl
e25ab8e305 Delete stale comment. Thanks, Eric!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204530 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-21 22:58:25 +00:00
Adrian Prantl
0fb178b831 Dwarf Debug: Remove some cargo-cult type uniquing. Scopes do not have
an ID, so this is a noop.
Thanks Manman for catching this!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204528 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-21 22:16:32 +00:00
Arnaud A. de Grandmaison
96c049d56d Remove some dead assignements found by scan-build
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204526 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-21 21:54:46 +00:00
Manman Ren
8dbd561a88 Register allocator: add condition to hoist a spill to outer loop.
We make sure a spill is not hoisted to a hotter outer loop by adding
a condition. Hoist a spill to outer loop if there are multiple dependents
(it can be beneficial if more than one dependents are hoisted) or
if DepSV (the hoisting source) is hotter than SV (the hoisting destination).

rdar://16268194


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204522 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-21 21:46:24 +00:00
David Blaikie
4d221b3e89 DebugInfo: Omit DW_AT_addr_base from skeletal type units.
Type units have no addresses, so there's no need for DW_AT_addr_base.
This removes another relocation from every skeletal type unit and brings
LLVM's skeletal type units in line with GCC's (containing only
GNU_dwo_name (strp), comp_dir (strp), and GNU_pubnames (flag_present)).

Cary's got some ideas about using str_index in the .o file to reduce
those last two relocations (well, replace two relocations with one
relocation (pointing to the string index) and two indicies)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204506 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-21 20:27:21 +00:00
Kevin Qin
c53b3dbc20 Fix an assertion caused by using inline asm with indirect register inputs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204425 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-21 02:14:50 +00:00
Mark Seaborn
9bb9615e1f Remove LowerInvoke's obsolete "-enable-correct-eh-support" option
This option caused LowerInvoke to generate code using SJLJ-based
exception handling, but there is no code left that interprets the
jmp_buf stack that the resulting code maintained (llvm.sjljeh.jblist).
This option has been obsolete for a while, and replaced by
SjLjEHPrepare.

This leaves the default behaviour of LowerInvoke, which is to convert
invokes to calls.

Differential Revision: http://llvm-reviews.chandlerc.com/D3136

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204388 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-20 19:54:47 +00:00
Eric Christopher
56210e69eb Typo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204378 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-20 19:16:20 +00:00
Eric Christopher
8b97f004cb Reapply DW_AT_low/high_pc patch:
Use the range machinery for DW_AT_ranges and DW_AT_high/lo_pc.

    This commit moves us from a single range per subprogram to extending
    ranges if we are:

    a) In the same section, and
    b) In the same enclosing CU.

    This means we have more fine grained ranges for compile units, and fewer
    ranges overall when we have multiple functions in the same CU
    adjacent to each other in the object file.

    Also remove all of the earlier hacks around this functionality for
    function sections etc. Also update all of the testcases to take into
    account the merging functionality.

with a fix for location entries in the debug_loc section:

Make sure that debug loc entries are relative to the low_pc
of the compile unit. This means that when we only have a single
range that the offset should be just relative to the low_pc
of the unit, for multiple ranges for a CU this means that we'll be
relative to 0 which we emit along with DW_AT_ranges.

This mostly shows up with linked binaries, so add a testcase with
multiple CUs so that our location is going to be offset of a CU
with a non-zero low_pc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204377 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-20 19:16:16 +00:00
David Blaikie
b5a1fccdc5 Add comments from Eric's review of r204094.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204358 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-20 17:05:45 +00:00
Eric Christopher
5a8743ef85 Revert "Use the range machinery for DW_AT_ranges and DW_AT_high/lo_pc."
This appears to trigger failures with optimization and function arguments somehow.

This reverts commit r204277.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204286 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-20 00:12:06 +00:00
Eric Christopher
f2a52c372d Use the range machinery for DW_AT_ranges and DW_AT_high/lo_pc.
This commit moves us from a single range per subprogram to extending
ranges if we are:

a) In the same section, and
b) In the same enclosing CU.

This means we have more fine grained ranges for compile units, and fewer
ranges overall when we have multiple functions in the same CU
adjacent to each other in the object file.

Also remove all of the earlier hacks around this functionality for
function sections etc. Also update all of the testcases to take into
account the merging functionality.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204277 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-19 22:42:36 +00:00
David Blaikie
56ce2f5ab8 DebugInfo: Use the comp_dir of the referencing type units when building debug_line.dwo
This isn't a complete fix - it falls back to non-comp_dir when multiple
compile units are in play. Adding a map of comp_dir to table is part of
the more general solution, but I gave up (in the short term) when I
realized I'd also have to calculate the size of each type unit so as to
produce correct DW_AT_stmt_list attributes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204202 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-19 00:11:28 +00:00
Jim Grosbach
e133cd2ea2 MachO: Emit a version-min load command when possible.
When deployment target version information is available, emit it to the
target streamer for inclusion in the object file.

rdar://11337778

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204191 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 22:09:08 +00:00
Eric Christopher
18d3426b89 More header and forward declaration cleanup.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204183 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 21:44:12 +00:00
Eric Christopher
a673745a34 Add back the headers we're getting via (likely) transitive includes.
We really do use these things in the header.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204180 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 20:58:35 +00:00
Eric Christopher
7f22dc90ad Fix for coding style.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204177 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 20:39:54 +00:00
Eric Christopher
994c303f24 Remove a bunch of unnecessary includes and forward declarations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204176 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 20:37:10 +00:00
Raul E. Silvera
370981ad17 Add support for scalarizing/splitting vector bswap.
Summary:
  SLP Vectorization of intrinsics (r203707) has exposed cases where the
  expansion of vector bswap is failing (PR19151).

Reviewers: hfinkel

CC: chandlerc

Differential Revision: http://llvm-reviews.chandlerc.com/D3104

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204163 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 17:49:12 +00:00
Adrian Prantl
e1ea4faca1 Debug info: Remove OdrMemberMap from DwarfDebug, it's not necessary.
Follow-up to r203982.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204162 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 17:41:15 +00:00
Andrea Di Biagio
6077ca9abb [DAGCombiner] teach how to simplify xor/and/or nodes according to the following rules:
1)  (AND (shuf (A, C, Mask), shuf (B, C, Mask)) -> shuf (AND (A, B), C, Mask)
 2)  (OR  (shuf (A, C, Mask), shuf (B, C, Mask)) -> shuf (OR  (A, B), C, Mask)
 3)  (XOR (shuf (A, C, Mask), shuf (B, C, Mask)) -> shuf (XOR (A, B), V_0, Mask)

 4)  (AND (shuf (C, A, Mask), shuf (C, B, Mask)) -> shuf (C, AND (A, B), Mask)
 5)  (OR  (shuf (C, A, Mask), shuf (C, B, Mask)) -> shuf (C, OR  (A, B), Mask)
 6)  (XOR (shuf (C, A, Mask), shuf (C, B, Mask)) -> shuf (V_0, XOR (A, B), Mask)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204160 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 17:12:59 +00:00
Adrian Prantl
ff5abbb4d3 DwarfDebug: Only unique retained types instead of all types.
This is a follow-up to r203983 based on feedback from dblaikie and mren (Thanks!)
No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204107 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 02:35:03 +00:00
Adrian Prantl
5e8144df32 Switch the type field in DIVariable and DIGlobalVariable over to DITypeRefs.
This allows us to catch more opportunities for ODR-based type uniquing
during LTO.
Paired commit with CFE which updates some testcases to verify the new
DIBuilder behavior.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204106 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 02:34:58 +00:00
Adrian Prantl
4d82ca7462 Replace unnecessary #include directive with forward declarations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204104 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 02:34:52 +00:00
Eric Christopher
635ed6dfe9 Add explanatory comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204103 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 02:18:27 +00:00
Eric Christopher
b005e96324 Shorten DotDebugLocEntry to just DebugLocEntry and reformat.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204102 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 02:18:24 +00:00
David Blaikie
c5b39af329 DebugInfo: Avoid emitting standard opcode lengths in debug_line.dwo headers where opcodes are never used anyway
Introduce a slightly tighter wrapper around the header structure that
handles this use case. (MCDwarfDwoLineTable)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204101 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 02:13:23 +00:00
David Blaikie
9c1e56a84d DebugInfo: Implement debug_line.dwo for file names used in type units during -gsplit-dwarf
This removes an attribute (and more importantly, a relocation) from
skeleton type units and removes some unnecessary file names from the
debug_line section that remains in the .o (and linked executable) file.

There's still a few places we could shave off some more space here:

* use compilation dir of the underlying compilation unit (since all the
  type units share that compilation dir - though this would be more
  complicated in LTO cases where they don't (keep a map of compilation
  dir->line table header?))

* Remove some of the unnecessary header fields from the line table since
  they're not needed in this situation (about 12 bytes per table).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204099 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 01:17:26 +00:00
David Blaikie
2a12c4e5bd DebugInfo: Do not rely on the compilation dir (index 0) for files in line tables shared between compilation units
When emitting assembly there's no support for emitting separate line
tables for each compilation unit - so LLVM emits .loc directives
producing a single line table.

Line tables have an implicit directory (index 0) equal to the
compilation directory (DW_AT_comp_dir) of the compilation unit that
references them.

If multiple compilation units (with possibly disparate compilation
directories) reference the same line table, we must avoid relying on
this ambiguous directory.

Achieve this my simply not setting the compilation directory on the line
table when we're in this situation (multiple units while emitting
assembly).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204094 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-18 00:11:48 +00:00
David Blaikie
1881227389 DebugInfo: Move getOrCreateSourceID from DwarfDebug to DwarfCompileUnit
We still do a few lookups into the line table mapping in MCContext that
could be factored out into a single lookup (rather than looking it up
once for the table label, once to set the compilation unit, once for
each time we need a file ID, etc... ) but assembly output complicates
that somewhat as we still need a virtual dispatch back to the
MCAsmStreamer in that case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204092 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 23:53:25 +00:00
David Blaikie
2879a6caa8 DebugInfo: Move line table zero-directory-index (compilation dir) handling into MCDwarf
Our handling of compilation directory in DwarfDebug was broken
(incorrectly using the 'last' compilation directory (that of the last
CU in the metadata list) for all function emission in any CU). By moving
this handling down into MCDwarf the issue is fixed as the compilation
dir is tracked correctly per line table.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204089 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 23:29:40 +00:00
Owen Anderson
92fca73d52 Switch a number of loops in lib/CodeGen over to range-based for-loops, now that
the MachineRegisterInfo iterators are compatible with it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204075 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 19:36:09 +00:00
Matt Arsenault
94bdb453a4 Make DAGCombiner work on vector bitshifts with constant splat vectors.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204071 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 18:58:01 +00:00
David Blaikie
daeeb37373 DebugInfo: Use MC line table file entry uniquing for non-asm input as well.
See r204027 for the precursor to this that applied to asm debug info.

This required some non-obvious API changes to handle the case of asm
output (we never go asm->asm so this didn't come up in r204027): the
modification of the file/directory name by MCDwarfLineTableHeader needed
to be reflected in the MCAsmStreamer caller so it could print the
appropriate .file directive, so those StringRef parameters are now
non-const ref (in/out) parameters rather than just const.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204069 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 18:13:58 +00:00
Adam Nemet
8c8fe42a0d [VectorLegalizer/X86] Don't unvectorize fp_to_uint for v8f32->v8i16
Rather than LegalizeAction::Expand, this needs LegalizeAction::Promote to get
promoted to fp_to_sint v8f32->v8i32.  This is a legal operation on AVX.

For that to work properly, we also need to teach the legalizer about the
specific promotion required here.  The default vector promotion uses
bitcasting to a vector type of the same total size.  We want to promote the
vector element type, effectively widening the operation and then truncating
the result.  This is analogous to the current logic of how int_to_fp is
promoted.

The change also factors out some code from the int_to_fp promotion code to
ValueType::widenIntegerVectorElementType.  This is now shared between
int_to_fp and fp_to_int.

There is no longer need for the custom lowering of fp_to_sint f32->v8i16 in
X86.  It can now go through the new target-independent fp_to_*int promotion
logic.

I also checked that no other target uses Promote for these ops yet, so there
shouldn't be any unexpected change in behavior.

Fixes <rdar://problem/16202247>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204058 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 17:06:14 +00:00
Lang Hames
3dd951e842 [X86] New and improved VZeroUpperInserter optimization.
- Adds support for inserting vzerouppers before tail-calls.
  This is enabled implicitly by having MachineInstr::copyImplicitOps preserve
  regmask operands, which allows VZeroUpperInserter to see where tail-calls use
  vector registers.

- Fixes a bug that caused the previous version of this optimization to miss some
  vzeroupper insertion points in loops. (Loops-with-vector-code that followed
  loops-without-vector-code were mistakenly overlooked by the previous version).

- New algorithm never revisits instructions.

Fixes <rdar://problem/16228798>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204021 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 01:22:54 +00:00
Arnaud A. de Grandmaison
3c143dde40 Remove some dead assignements found by scan-build
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204013 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-15 22:13:15 +00:00
Adrian Prantl
1d8c02bef3 Debug info: Unique types before emitting them to DWARF, where applicable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203983 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 23:08:29 +00:00
Adrian Prantl
7e1a3830ca Debug Info: Fix LTO type uniquing for C++ member declarations
based on the ODR.

This adds an OdrMemberMap to DwarfDebug which is used to unique C++
member function declarations based on the unique identifier of their
containing class and their mangled name.
We can't use the usual DIRef mechanism here because DIScopes are indexed
using their entire MDNode, including decl_file and decl_line, which need
not be unique (see testcase).

Prior to this change multiple redundant member function declarations would
end up in the same uniqued DW_TAG_class_type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203982 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 23:08:25 +00:00
Adrian Prantl
be4056d0a5 typo
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203980 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 23:08:17 +00:00
Eric Christopher
f90e07f6c3 Remove command line option for CU hashing. This is on by default now.
Fix up testcases and use of flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203973 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 21:20:07 +00:00
Eric Christopher
82899d9d60 If we see that we're emitting code for a function that doesn't have
any lexical scopes then go ahead and turn on DW_AT_ranges for the
compile unit since we would be claiming to describe in the CU
a range for which we don't have information in the CU otherwise.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203969 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 20:53:49 +00:00
Eric Christopher
895ec9ed94 Remove the -generate-dwarf-cu-ranges flag.
Rewrite a couple of testcases to cover areas that would be normally
by turning it on into testcases that will follow the logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203968 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 20:53:43 +00:00
David Blaikie
2bc7715df9 DwarfDebug: Remove some needless recursion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203946 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 16:33:32 +00:00
Owen Anderson
b6f478aa66 Revert r203883 (which was more of a bandaid) and fix the real underlying
issue in that the new MachineRegisterInfo bundle iterators didn't
dereference to the START of the bundle, while the old skipBundle()
method did.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203890 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 05:02:18 +00:00
Pete Cooper
757ed6daf4 Fix issue with r203865. The old behaviour would get a MachineOperand then find the MI for the bundle the MI was in. The new behaviour was failing to get the parent bundle and instead just used the MI from the MachineOperand
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203883 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-14 02:28:05 +00:00
Eric Christopher
70506c5fdd Use DW_AT_linkage_name when we're emitting DWARF4 or above.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203867 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-13 23:26:25 +00:00
Rafael Espindola
1f21e0dd0d Remove the linker_private and linker_private_weak linkages.
These linkages were introduced some time ago, but it was never very
clear what exactly their semantics were or what they should be used
for. Some investigation found these uses:

* utf-16 strings in clang.
* non-unnamed_addr strings produced by the sanitizers.

It turns out they were just working around a more fundamental problem.
For some sections a MachO linker needs a symbol in order to split the
section into atoms, and llvm had no idea that was the case. I fixed
that in r201700 and it is now safe to use the private linkage. When
the object ends up in a section that requires symbols, llvm will use a
'l' prefix instead of a 'L' prefix and things just work.

With that, these linkages were already dead, but there was a potential
future user in the objc metadata information. I am still looking at
CGObjcMac.cpp, but at this point I am convinced that linker_private
and linker_private_weak are not what they need.

The objc uses are currently split in

* Regular symbols (no '\01' prefix). LLVM already directly provides
whatever semantics they need.
* Uses of a private name (start with "\01L" or "\01l") and private
linkage. We can drop the "\01L" and "\01l" prefixes as soon as llvm
agrees with clang on L being ok or not for a given section. I have two
patches in code review for this.
* Uses of private name and weak linkage.

The last case is the one that one could think would fit one of these
linkages. That is not the case. The semantics are

* the linker will merge these symbol by *name*.
* the linker will hide them in the final DSO.

Given that the merging is done by name, any of the private (or
internal) linkages would be a bad match. They allow llvm to rename the
symbols, and that is really not what we want. From the llvm point of
view, these objects should really be (linkonce|weak)(_odr)?.

For now, just keeping the "\01l" prefix is probably the best for these
symbols. If we one day want to have a more direct support in llvm,
IMHO what we should add is not a linkage, it is just a hidden_symbol
attribute. It would be applicable to multiple linkages. For example,
on weak it would produce the current behavior we have for objc
metadata. On internal, it would be equivalent to private (and we
should then remove private).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203866 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-13 23:18:37 +00:00