The verifier currently runs three times in LTO: (1) after parsing, (2)
at the beginning of the optimization pipeline, and (3) at the end of it.
The first run is important, since we're not sure where the bitcode comes
from and it's nice to validate it, but in release builds the extra runs
aren't appropriate.
This commit:
- Allows these runs to be disabled in LTOCodeGenerator.
- Adds command-line options to llvm-lto.
- Adds command-line options to libLTO.dylib, and disables the verifier
by default in release builds (based on NDEBUG).
This shaves about 3.5% off the runtime of ld64 when linking
verify-uselistorder with -flto -g.
rdar://22509081
llvm-svn: 247729
llvm::splitCodeGen is a function that implements the core of parallel LTO
code generation. It uses llvm::SplitModule to split the module into linkable
partitions and spawning one code generation thread per partition. The function
produces multiple object files which can be linked in the usual way.
This has been threaded through to LTOCodeGenerator (and llvm-lto for testing
purposes). Separate patches will add parallel LTO support to the gold plugin
and lld.
Differential Revision: http://reviews.llvm.org/D12260
llvm-svn: 246236
This change moves LTOCodeGenerator's ownership of the merged module to a
field of type std::unique_ptr<Module>. This helps simplify parts of the code
and clears the way for the module to be consumed by LLVM CodeGen (see D12132
review comments).
Differential Revision: http://reviews.llvm.org/D12205
llvm-svn: 245891
This allows us to remove a bunch of code in LTOCodeGenerator and llvm-lto
and has the side effect of improving error handling in the libLTO C API.
llvm-svn: 245756
Start using C++ types such as StringRef and MemoryBuffer in the C++ LTO
API. In doing so, clarify the ownership of the native object file: the caller
now owns it, not the LTOCodeGenerator. The C libLTO library has been modified
to use a derived class of LTOCodeGenerator that owns the object file.
Differential Revision: http://reviews.llvm.org/D10114
llvm-svn: 238776
This change also introduces a link-time optimization level of 1. This
optimization level runs only the globaldce pass as well as cleanup passes for
passes that run at -O0, specifically simplifycfg which cleans up lowerbitsets.
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150316/266951.html
llvm-svn: 232769
When debugging LTO issues with ld64, we use -save-temps to save the merged
optimized bitcode file, then invoke ld64 again on the single bitcode file to
speed up debugging code generation passes and ld64 stuff after code generation.
llvm linking a single bitcode file via lto_codegen_add_module will generate a
different bitcode file from the single input. With the newly-added
lto_codegen_set_module, we can make sure the destination module is the same as
the input.
lto_codegen_set_module will transfer the ownship of the module to code
generator.
rdar://19024554
llvm-svn: 230290
Add coverage in `llvm-lto` for the API exposed by libLTO to create
modules in local contexts.
The goal here isn't to test the symbol-related API extensively, just to
confirm that these modules work at all. (I'll be shifting code around
soon that should be NFC and I realized there was no test coverage.)
llvm-svn: 224408
We used to always vectorize (slp and loop vectorize) in the LTO pass pipeline.
r220345 changed it so that we used the PassManager's fields 'LoopVectorize' and
'SLPVectorize' out of the desire to be able to disable vectorization using the
cl::opt flags 'vectorize-loops'/'slp-vectorize' which the before mentioned
fields default to.
Unfortunately, this turns off vectorization because those fields
default to false.
This commit adds flags to the LTO library to disable lto vectorization which
reconciles the desire to optionally disable vectorization during LTO and
the desired behavior of defaulting to enabled vectorization.
We really want tools to set PassManager flags directly to enable/disable
vectorization and not go the route via cl::opt flags *in*
PassManagerBuilder.cpp.
llvm-svn: 220652
r206400 and r209442 added remarks that are disabled by default.
However, if a diagnostic handler is registered, the remarks are sent
unfiltered to the handler. This is the right behaviour for clang, since
it has its own filters.
However, the diagnostic handler exposed in the LTO API receives only the
severity and message. It doesn't have the information to filter by pass
name. For LTO, disabled remarks should be filtered by the producer.
I've changed `LLVMContext::setDiagnosticHandler()` to take a `bool`
argument indicating whether to respect the built-in filters. This
defaults to `false`, so other consumers don't have a behaviour change,
but `LTOCodeGenerator::setDiagnosticHandler()` sets it to `true`.
To make this behaviour testable, I added a `-use-diagnostic-handler`
command-line option to `llvm-lto`.
This fixes PR21108.
llvm-svn: 218784
Take a StringRef instead of a "const char *".
Take a "std::error_code &" instead of a "std::string &" for error.
A create static method would be even better, but this patch is already a bit too
big.
llvm-svn: 216393
This rename makes it easier to identify the specific overload being called
in each particular case and makes future refactorings easier.
Differential Revision: http://reviews.llvm.org/D4370
llvm-svn: 212302
This adds support for an -mattr option to the gold plugin and to llvm-lto. This
allows the caller to specify details of the subtarget architecture, like +aes,
or +ssse3 on x86. Note that this requires a change to the include/llvm-c/lto.h
interface: it adds a function lto_codegen_set_attr and it increments the
version of the interface.
llvm-svn: 207279
This compiles with no changes to clang/lld/lldb with MSVC and includes
overloads to various functions which are used by those projects and llvm
which have OwningPtr's as parameters. This should allow out of tree
projects some time to move. There are also no changes to libs/Target,
which should help out of tree targets have time to move, if necessary.
llvm-svn: 203083
After this I will set the default back to F_None. The advantage is that
before this patch forgetting to set F_Binary would corrupt a file on windows.
Forgetting to set F_Text produces one that cannot be read in notepad, which
is a better failure mode :-)
llvm-svn: 202052
The same code (~20 lines) for initializing a TargetOptions object from CodeGen
cmdline flags is duplicated 4 times in 4 different tools. This patch moves it
into a utility function.
Since the CodeGen/CommandFlags.h file defines cl::opt flags in a header, it's
a bit of a touchy situation because we should only link them into tools. So this
patch puts the init function in the header.
llvm-svn: 201699
There are two ways one could implement hiding of linkonce_odr symbols in LTO:
* LLVM tells the linker which symbols can be hidden if not used from native
files.
* The linker tells LLVM which symbols are not used from other object files,
but will be put in the dso symbol table if present.
GOLD's API is the second option. It was implemented almost 1:1 in llvm by
passing the list down to internalize.
LLVM already had partial support for the first option. It is also very similar
to how ld64 handles hiding these symbols when *not* doing LTO.
This patch then
* removes the APIs for the DSO list.
* marks LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN all linkonce_odr unnamed_addr
global values and other linkonce_odr whose address is not used.
* makes the gold plugin responsible for handling the API mismatch.
llvm-svn: 193800
Generalize the API so we can distinguish symbols that are needed just for a DSO
symbol table from those that are used from some native .o.
The symbols that are only wanted for the dso symbol table can be dropped if
llvm can prove every other dso has a copy (linkonce_odr) and the address is not
important (unnamed_addr).
llvm-svn: 191922
Duncan P. N. Exon Smith