Commit Graph

355 Commits

Author SHA1 Message Date
Eli Bendersky
030f63a397 Expose an InitToTextSection through MCStreamer.
The aim of this patch is to fix the following piece of code in the
platform-independent AsmParser:

void AsmParser::CheckForValidSection() {
  if (!ParsingInlineAsm && !getStreamer().getCurrentSection()) {
    TokError("expected section directive before assembly directive");
    Out.SwitchSection(Ctx.getMachOSection(
                        "__TEXT", "__text",
                        MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
                        0, SectionKind::getText()));
  }
}

This was added for the "-n" option of llvm-mc.

The proposed fix adds another virtual method to MCStreamer, called
InitToTextSection. Conceptually, it's similar to the existing
InitSections which initializes all common sections and switches to
text. The new method is implemented by each platform streamer in a way
that it sees fit. So AsmParser can now do this:

void AsmParser::CheckForValidSection() {
  if (!ParsingInlineAsm && !getStreamer().getCurrentSection()) {
    TokError("expected section directive before assembly directive");
    Out.InitToTextSection();
  }
}

Which is much more reasonable.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172450 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-14 19:04:57 +00:00
Eli Bendersky
6c1d4972cf Add the align_to_end option to .bundle_lock in the MC implementation of aligned
bundling. The document describing this feature and the implementation has also
been updated:

https://sites.google.com/a/chromium.org/dev/nativeclient/pnacl/aligned-bundling-support-in-llvm


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171797 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-07 21:51:08 +00:00
Chandler Carruth
aeef83c6af Switch TargetTransformInfo from an immutable analysis pass that requires
a TargetMachine to construct (and thus isn't always available), to an
analysis group that supports layered implementations much like
AliasAnalysis does. This is a pretty massive change, with a few parts
that I was unable to easily separate (sorry), so I'll walk through it.

The first step of this conversion was to make TargetTransformInfo an
analysis group, and to sink the nonce implementations in
ScalarTargetTransformInfo and VectorTargetTranformInfo into
a NoTargetTransformInfo pass. This allows other passes to add a hard
requirement on TTI, and assume they will always get at least on
implementation.

The TargetTransformInfo analysis group leverages the delegation chaining
trick that AliasAnalysis uses, where the base class for the analysis
group delegates to the previous analysis *pass*, allowing all but tho
NoFoo analysis passes to only implement the parts of the interfaces they
support. It also introduces a new trick where each pass in the group
retains a pointer to the top-most pass that has been initialized. This
allows passes to implement one API in terms of another API and benefit
when some other pass above them in the stack has more precise results
for the second API.

The second step of this conversion is to create a pass that implements
the TargetTransformInfo analysis using the target-independent
abstractions in the code generator. This replaces the
ScalarTargetTransformImpl and VectorTargetTransformImpl classes in
lib/Target with a single pass in lib/CodeGen called
BasicTargetTransformInfo. This class actually provides most of the TTI
functionality, basing it upon the TargetLowering abstraction and other
information in the target independent code generator.

The third step of the conversion adds support to all TargetMachines to
register custom analysis passes. This allows building those passes with
access to TargetLowering or other target-specific classes, and it also
allows each target to customize the set of analysis passes desired in
the pass manager. The baseline LLVMTargetMachine implements this
interface to add the BasicTTI pass to the pass manager, and all of the
tools that want to support target-aware TTI passes call this routine on
whatever target machine they end up with to add the appropriate passes.

The fourth step of the conversion created target-specific TTI analysis
passes for the X86 and ARM backends. These passes contain the custom
logic that was previously in their extensions of the
ScalarTargetTransformInfo and VectorTargetTransformInfo interfaces.
I separated them into their own file, as now all of the interface bits
are private and they just expose a function to create the pass itself.
Then I extended these target machines to set up a custom set of analysis
passes, first adding BasicTTI as a fallback, and then adding their
customized TTI implementations.

The fourth step required logic that was shared between the target
independent layer and the specific targets to move to a different
interface, as they no longer derive from each other. As a consequence,
a helper functions were added to TargetLowering representing the common
logic needed both in the target implementation and the codegen
implementation of the TTI pass. While technically this is the only
change that could have been committed separately, it would have been
a nightmare to extract.

The final step of the conversion was just to delete all the old
boilerplate. This got rid of the ScalarTargetTransformInfo and
VectorTargetTransformInfo classes, all of the support in all of the
targets for producing instances of them, and all of the support in the
tools for manually constructing a pass based around them.

Now that TTI is a relatively normal analysis group, two things become
straightforward. First, we can sink it into lib/Analysis which is a more
natural layer for it to live. Second, clients of this interface can
depend on it *always* being available which will simplify their code and
behavior. These (and other) simplifications will follow in subsequent
commits, this one is clearly big enough.

Finally, I'm very aware that much of the comments and documentation
needs to be updated. As soon as I had this working, and plausibly well
commented, I wanted to get it committed and in front of the build bots.
I'll be doing a few passes over documentation later if it sticks.

Commits to update DragonEgg and Clang will be made presently.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171681 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-07 01:37:14 +00:00
Chandler Carruth
b24ce3ec45 Fix another place where we build the TTI pass to the new interface.
Sorry for the noise here, 'make check' doesn't build this code. =/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171623 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-05 11:54:35 +00:00
Chandler Carruth
0b8c9a80f2 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-02 11:36:10 +00:00
Chandler Carruth
7f00f87767 Sort a few more #include lines in tools/... unittests/... and utils/...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171363 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-02 10:26:28 +00:00
Eli Bendersky
4766ef41b3 Aligned bundling support. Following the discussion here:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-December/056754.html

The proposal and implementation are fully documented here:
https://sites.google.com/a/chromium.org/dev/nativeclient/pnacl/aligned-bundling-support-in-llvm

Tests will follow shortly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170718 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 19:05:53 +00:00
Reed Kotler
2c3a4641a7 This patch is needed to make c++ exceptions work for mips16.
Mips16 is really a processor decoding mode (ala thumb 1) and in the same
program, mips16 and mips32 functions can exist and can call each other.

If a jal type instruction encounters an address with the lower bit set, then
the processor switches to mips16 mode (if it is not already in it). If the
lower bit is not set, then it switches to mips32 mode.

The linker knows which functions are mips16 and which are mips32.
When relocation is performed on code labels, this lower order bit is
set if the code label is a mips16 code label.

In general this works just fine, however when creating exception handling
tables and dwarf, there are cases where you don't want this lower order
bit added in.

This has been traditionally distinguished in gas assembly source by using a
different syntax for the label.

lab1:      ; this will cause the lower order bit to be added
lab2=.     ; this will not cause the lower order bit to be added

In some cases, it does not matter because in dwarf and debug tables
the difference of two labels is used and in that case the lower order
bits subtract each other out.

To fix this, I have added to mcstreamer the notion of a debuglabel.
The default is for label and debug label to be the same. So calling
EmitLabel and EmitDebugLabel produce the same result.

For various reasons, there is only one set of labels that needs to be
modified for the mips exceptions to work. These are the "$eh_func_beginXXX" 
labels.

Mips overrides the debug label suffix from ":" to "=." .

This initial patch fixes exceptions. More changes most likely
will be needed to DwarfCFException to make all of this work
for actual debugging. These changes will be to emit debug labels in some
places where a simple label is emitted now.

Some historical discussion on this from gcc can be found at:
http://gcc.gnu.org/ml/gcc-patches/2008-08/msg00623.html
http://gcc.gnu.org/ml/gcc-patches/2008-11/msg01273.html 



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170279 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-16 04:00:45 +00:00
NAKAMURA Takumi
f2a68db426 llvm/tools: Add #include "llvm/TargetTransformInfo.h"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169817 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-11 05:53:37 +00:00
Rafael Espindola
613abf3fa6 Change some functions to take const pointers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169812 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-11 03:10:43 +00:00
Bill Wendling
50f318384c Revert r169656.
The linker will call `lto_codegen_add_must_preserve_symbol' on all globals that
should be kept around. The linker will pretend that a dylib is being created.
<rdar://problem/12528059>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169770 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-10 21:33:45 +00:00
NAKAMURA Takumi
60608b924d [CMake] Update dependencies to intrinsics_gen corresponding to r169711.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169724 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-10 05:27:15 +00:00
Bill Wendling
12a38adc58 Revert to old behavior until linker can pass export-dynamic option.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169720 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-10 02:51:16 +00:00
Bill Wendling
f62b9cd890 Add the `lto_codegen_set_export_dynamic' function.
This function sets the `_exportDynamic' ivar. When that's set, we export all
symbols (e.g. we don't run the internalize pass). This is equivalent to the
`--export-dynamic' linker flag in GNU land:

--export-dynamic
  When creating a dynamically linked executable, add all symbols to the dynamic
  symbol table. The dynamic symbol table is the set of symbols which are visible
  from dynamic objects at run time. If you do not use this option, the dynamic
  symbol table will normally contain only those symbols which are referenced by
  some dynamic object mentioned in the link. If you use dlopen to load a dynamic
  object which needs to refer back to the symbols defined by the program, rather
  than some other dynamic object, then you will probably need to use this option
  when linking the program itself.

The Darwin linker will support this via the `-export_dynamic' flag. We should
modify clang to support this via the `-rdynamic' flag.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169656 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-08 00:18:16 +00:00
Jim Grosbach
68a590df13 Add C API for specifying CPU to the disassembler.
It was a nasty oversight that we didn't include this when we added this
API in the first place. Blech.

rdar://12839439

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169653 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-07 23:53:27 +00:00
Chandler Carruth
f010c464a1 Sort the #include lines for tools/...
Again, tools are trickier to pick the main module header for than
library source files. I've started to follow the pattern of using
LLVMContext.h when it is included as a stub for program source files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169252 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-04 10:44:52 +00:00
Pedro Artigas
6eda081345 One more step towards making doInitialization and doFinalization useful for
start up and clean up module passes, now that ASAN and TSAN are fixed the
tests pass



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168905 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 17:47:05 +00:00
Owen Anderson
9780d352b9 Revert r168635 "Step towards implementation of pass manager with doInitialization and doFinalization per module detangled from runOn?? calls, still has temporary code not to break ASAN to be removed when that pass conforms to the proposed model".
It appears to have broken at least one buildbot.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168654 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 00:53:24 +00:00
Owen Anderson
0d30d30d58 Step towards implementation of pass manager with doInitialization and doFinalization per module detangled from runOn?? calls, still has temporary code not to break ASAN to be removed when that pass conforms to the proposed model
Patch by Pedro Artigas, with feedback from by Chandler Carruth.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168635 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-26 23:54:47 +00:00
Benjamin Kramer
8a2ce5d329 libLTO: Add a utility method to initialize the disassemblers.
Necessary to give disassembler users (like darwin's otool) a possibility to
dlopen libLTO and still initialize the required LLVM bits. This used to go
through libMCDisassembler but that's a gross layering violation, the MC layer
can't pull in functions from the targets. Adding a function to libLTO is a bit
of a hack but not worse than exposing other disassembler bits from libLTO.

Fixes PR14362.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168545 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-24 16:59:10 +00:00
Owen Anderson
40b6fdb81e Add doInitialization and doFinalization methods to ModulePass's, to allow them to be re-initialized and reused on multiple Module's.
Patch by Pedro Artigas.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168008 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-15 00:14:15 +00:00
Kevin Enderby
3ed0316f75 Add support for annotated disassembly output for X86 and arm.
Per the October 12, 2012 Proposal for annotated disassembly output sent out by
Jim Grosbach this set of changes implements this for X86 and arm.  The llvm-mc
tool now has a -mdis option to produced the marked up disassembly and a couple
of small example test cases have been added.

rdar://11764962


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166445 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-22 22:31:46 +00:00
Nadav Rotem
cbd9a19b5d Reapply the TargerTransformInfo changes, minus the changes to LSR and Lowerinvoke.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166248 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 23:22:48 +00:00
Bob Wilson
3b9a911efc Temporarily revert the TargetTransform changes.
The TargetTransform changes are breaking LTO bootstraps of clang.  I am
working with Nadav to figure out the problem, but I am reverting it for now
to get our buildbots working.

This reverts svn commits: 165665 165669 165670 165786 165787 165997
and I have also reverted clang svn 165741

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166168 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 05:43:52 +00:00
Nadav Rotem
88bcf797ab LTO also needs to initialize the TargetTransform infrastructure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165997 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 22:50:02 +00:00
Bob Wilson
47ed8a161c Set default CPU for Darwin targets with LTO. <rdar://problem/12457841>
This is a temporary hack until Bill's project to record command line options
in the LLVM IR is ready. Clang currently sets a default CPU but that isn't
recorded anywhere and it doesn't get used in the final LTO compilation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165809 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-12 17:39:25 +00:00
Bill Wendling
c33b9304da Place temporary LTO files into their own subdirectory.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165599 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-10 05:29:15 +00:00
Bob Wilson
52bcafe4bf Revert "Use a special path to place the .o files in."
This reverts commit 165428 in an attempt to get our buildbots going.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165574 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-09 23:59:01 +00:00
Bill Wendling
e57cb73153 Use a special path to place the .o files in.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165428 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-08 21:17:45 +00:00
Micah Villmow
791cfc211a Move TargetData to DataLayout.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165403 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-08 16:39:34 +00:00
Bill Wendling
10181ae49c Add an explicit -object_path_lto flag during linking with a uniquified temporary
file name if building Apple-style.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165185 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-03 23:52:10 +00:00
Bill Wendling
0b95a9949b Explicitly erase the file from disk if something bad happened. <rdar://problem/12184899>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163349 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 21:07:57 +00:00
Roman Divacky
5932429765 Stop casting away const qualifier needlessly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163258 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-05 22:26:57 +00:00
Chad Rosier
35907e9862 Add support for the --param ssp-buffer-size= driver option.
PR9673

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162284 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-21 16:15:24 +00:00
Bill Wendling
32811bef95 Change the linker_private_weak_def_auto' linkage to linkonce_odr_auto_hide' to
make it more consistent with its intended semantics.

The `linker_private_weak_def_auto' linkage type was meant to automatically hide
globals which never had their addresses taken. It has nothing to do with the
`linker_private' linkage type, which outputs the symbols with a `l' (ell) prefix
among other things.

The intended semantic is more like the `linkonce_odr' linkage type.

Change the name of the linkage type to `linkonce_odr_auto_hide'. And therefore
changing the semantics so that it produces the correct output for the linker.

Note: The old linkage name `linker_private_weak_def_auto' will still parse but
is not a synonym for `linkonce_odr_auto_hide'. This should be removed in 4.0.
<rdar://problem/11754934>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162114 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 18:33:14 +00:00
Bill Wendling
0ca36afc9d Remove some coding violations. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161530 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-08 22:03:50 +00:00
Bill Wendling
5682527882 Cache a commonly used reference.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161529 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-08 22:01:55 +00:00
Bill Wendling
eda3fc6734 Reduce indentation by early exiting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161356 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-06 22:52:45 +00:00
Bill Wendling
9ac0aaa6af Add a way to grab the target options from the LTO command line.
When the command line target options were removed from the LLVM libraries, LTO
lost its ability to specify things like `-disable-fp-elim'. Add this back by
adding the command line variables to the `lto' project.
<rdar://problem/12038729>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161353 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-06 21:34:54 +00:00
Evan Cheng
df42d41cd6 Forgot this patch in r159023.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159028 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-22 20:30:39 +00:00
Benjamin Kramer
a7542d5f87 Remove unused private fields found by clang's new -Wunused-private-field.
There are some that I didn't remove this round because they looked like
obvious stubs. There are dead variables in gtest too, they should be
fixed upstream.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158090 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-06 18:25:08 +00:00
David Blaikie
4f56a30e0d Reinstate -O3 for LTO.
This broke in r144788 when the CodeGenOpt option was moved from everywhere else
(specifically, from addPassesToEmitFile) to createTargetMachine. Since
LTOCodeGenerator wasn't passing the 4th argument, when the 4th parameter became
the 3rd, it silently continued to compile (int->bool conversion) but meant
something completely different.

This change preserves the existing (accidental) and previous (default)
semantics of the addPassesToEmitFile and restores the previous/intended
CodeGenOpt argument by passing it appropriately to createTargetMachine.

(discovered by pending changes to -Wconversion to catch constant->bool
conversions)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157705 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-30 18:42:51 +00:00
Rafael Espindola
383fd7afd9 Fix a use after free when the streamer is destroyed. Fixes pr12622.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156606 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-11 03:42:13 +00:00
Rafael Espindola
4d2e9d9a1c Remove lto_codegen_set_whole_program_optimization. It is a work in progress,
so we don't want it to show up in the stable 3.1 interface.

While at it, add a comment about why LTOCodeGenerator manually creates the
internalize pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154807 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-16 10:58:38 +00:00
Bill Wendling
64fae7587a Revert the 'EnableInitializing' flag. There is debate on whether we should run that pass by default in LTO.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154356 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09 23:16:51 +00:00
Bill Wendling
64d5b282c9 Apply the scope restrictions after parsing the command line options. There may be some which are used in that function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154348 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09 22:18:01 +00:00
Bill Wendling
a3706d6754 s/lto_codegen_whole_program_optimization/lto_codegen_set_whole_program_optimization/
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154312 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09 08:32:21 +00:00
Bill Wendling
3029a0c56a Add a hook to turn on the internalize pass through the LTO interface.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154306 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09 05:26:48 +00:00
Bill Wendling
97d9903236 The internalize pass can be dangerous for LTO.
Consider the following program:

$ cat main.c
void foo(void) { }

int main(int argc, char *argv[]) {
    foo();
    return 0;
}
$ cat bundle.c 
extern void foo(void);

void bar(void) {
     foo();
}
$ clang -o main main.c
$ clang -o bundle.so bundle.c -bundle -bundle_loader ./main
$ nm -m bundle.so
0000000000000f40 (__TEXT,__text) external _bar
                 (undefined) external _foo (from executable)
                 (undefined) external dyld_stub_binder (from libSystem)
$ clang -o main main.c -O4
$ clang -o bundle.so bundle.c -bundle -bundle_loader ./main
Undefined symbols for architecture x86_64:
  "_foo", referenced from:
      _bar in bundle-elQN6d.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

The linker was told that the 'foo' in 'main' was 'internal' and had no uses, so
it was dead stripped.

Another situation is something like:

define void @foo() {
  ret void
}

define void @bar() {
  call asm volatile "call _foo" ...
  ret void
}

The only use of 'foo' is inside of an inline ASM call. Since we don't look
inside those for uses of functions, we don't specify this as a "use."

Get around this by not invoking the 'internalize' pass by default. This is an
admitted hack for LTO correctness.
<rdar://problem/11185386>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154124 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-05 21:26:44 +00:00
Bill Wendling
90e7d4f6f0 Reformatting. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153928 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-03 03:56:52 +00:00