The primary motivation for this pass is to separate the call graph
analysis used by the new pass manager's CGSCC pass management from the
existing call graph analysis pass. That analysis pass is (somewhat
unfortunately) over-constrained by the existing CallGraphSCCPassManager
requirements. Those requirements make it *really* hard to cleanly layer
the needed functionality for the new pass manager on top of the existing
analysis.
However, there are also a bunch of things that the pass manager would
specifically benefit from doing differently from the existing call graph
analysis, and this new implementation tries to address several of them:
- Be lazy about scanning function definitions. The existing pass eagerly
scans the entire module to build the initial graph. This new pass is
significantly more lazy, and I plan to push this even further to
maximize locality during CGSCC walks.
- Don't use a single synthetic node to partition functions with an
indirect call from functions whose address is taken. This node creates
a huge choke-point which would preclude good parallelization across
the fanout of the SCC graph when we got to the point of looking at
such changes to LLVM.
- Use a memory dense and lightweight representation of the call graph
rather than value handles and tracking call instructions. This will
require explicit update calls instead of some updates working
transparently, but should end up being significantly more efficient.
The explicit update calls ended up being needed in many cases for the
existing call graph so we don't really lose anything.
- Doesn't explicitly model SCCs and thus doesn't provide an "identity"
for an SCC which is stable across updates. This is essential for the
new pass manager to work correctly.
- Only form the graph necessary for traversing all of the functions in
an SCC friendly order. This is a much simpler graph structure and
should be more memory dense. It does limit the ways in which it is
appropriate to use this analysis. I wish I had a better name than
"call graph". I've commented extensively this aspect.
This is still very much a WIP, in fact it is really just the initial
bits. But it is about the fourth version of the initial bits that I've
implemented with each of the others running into really frustrating
problms. This looks like it will actually work and I'd like to split the
actual complexity across commits for the sake of my reviewers. =] The
rest of the implementation along with lots of wiring will follow
somewhat more rapidly now that there is a good path forward.
Naturally, this doesn't impact any of the existing optimizer. This code
is specific to the new pass manager.
A bunch of thanks are deserved for the various folks that have helped
with the design of this, especially Nick Lewycky who actually sat with
me to go through the fundamentals of the final version here.
llvm-svn: 200903
necessary until we add analyses to the driver, but I have such an
analysis ready and wanted to split this out. This is actually exercised
by the existing tests of the new pass manager as the analysis managers
are cross-checked and validated by the function and module managers.
llvm-svn: 200901
It is not clear how much we should try to expose in getFlags. For example,
should there be a SF_Object and a SF_Text?
But for information that is already being exposed, we may as well use it in
llvm-nm.
llvm-svn: 200820
No functional change. Updated loops from:
for (I = scc_begin(), E = scc_end(); I != E; ++I)
to:
for (I = scc_begin(); !I.isAtEnd(); ++I)
for teh win.
llvm-svn: 200789
Until now, when a path in a gcno file included a directory, we would
emit our .gcov file in that directory, whereas gcov always emits the
file in the current directory. In doing so, this implements gcov's
strange name-mangling -p flag, which is needed to avoid clobbering
files when two with the same name exist in different directories.
The path mangling is a bit ugly and only handles unix-like paths, but
it's simple, and it doesn't make any guesses as to how it should
behave outside of what gcov documents. If we decide this should be
cross platform later, we can consider the compatibility implications
then.
llvm-svn: 200754
When gcov is run without gcda data, it acts as if the counts are all
zero and labels the file as - to indicate that there was no data. We
should do the same.
llvm-svn: 200740
COFF has only one symbol table.
MachO has a LC_DYSYMTAB, but that is not a symbol table, just extra info about
the one symbol table (LC_SYMTAB).
IR (coming soon) also has only one table.
llvm-svn: 200488
utohexstr provides a temporary string, making it unsafe to use with the Twine
interface which will not copy the string. Switch to using std::string.
llvm-svn: 200457
exp2 is not available on Windows. Fortunately, we are calculating powers of 2
with expontents within the range of [4,12]. Simply use an equivalent bitshift
operation to repair compilation with MSVC which does not provide this standard
function.
llvm-svn: 200454
Enhance the ARM specific parsing support in llvm-readobj to support attributes.
This allows for simpler tests to validate encoding of the build attributes as
specified in the ARM ELF specification.
llvm-svn: 200450
None of the object file formats reported error on iterator increment. In
retrospect, that is not too surprising: no object format stores symbols or
sections in a linked list or other structure that requires chasing pointers.
As a consequence, all error checking can be done on begin() and end().
This reduces the text segment of bin/llvm-readobj in my machine from 521233 to
518526 bytes.
llvm-svn: 200442
This is a bit imperfect, as these options don't show up in the help as
is and single dash variants are accepted, which differs from gcov.
Unfortunately, this seems to be as good as it gets with the cl::opt
machinery, so it'll do as an incremental step.
llvm-svn: 200419
This Properly capitalizes and clarifies the help output from
llvm-cov. It also puts the llvm-only / non-gcov-compatible options in
their own category.
llvm-svn: 200418
Currently, llvm-cov isn't command-line compatible with gcov, which
accepts a source file name as its first parameter and infers the gcno
and gcda file names from that. This change keeps our -gcda and -gcno
options available for convenience in overriding this behaviour, but
adds the required parameter and inference behaviour as a compatible
default.
llvm-svn: 200417
That bit is not documented in the PE/COFF spec published by Microsoft, so we
don't know the official name of it. I named this bit
IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VIRTUAL_ADDRESS because the bit is
reported as "high entropy virtual address" by dumpbin.exe,
llvm-svn: 200121
PE32+ supports 64 bit address space, but the file format remains 32 bit.
So its file format is pretty similar to PE32 (32 bit executable). The
differences compared to PE32 are (1) the lack of "BaseOfData" field and
(2) some of its data members are 64 bit.
In this patch, I added a new member function to get a PE32+ Header object to
COFFObjectFile class and made llvm-readobj to use it.
llvm-svn: 200117
This fixes a regression introduced by r182908, which broke
llvm-objdump's ability to display relocations inline in a disassembly
dump for ELF object files.
That change removed a SectionRelocMap from Object/ELF.h, which we
recreate in llvm-objdump.cpp.
I discovered this regression via an out-of-tree test
(test/NaCl/X86/pnacl-hides-sandbox-x86-64.ll) which used llvm-objdump.
Note that the "Unknown" string in the test output on i386 isn't quite
right, but this appears to be a pre-existing bug.
Differential Revision: http://llvm-reviews.chandlerc.com/D2559
llvm-svn: 200090
This enables IO error reports in both the child and server processes.
The scheme still isn't entirely satisfactory and output is jumbled but it beats
having no output at all. This will hopefully unblock ARM support (PR18057).
llvm-svn: 200017
Eliminates the LLI_BUILDING_CHILD build hack from r199885.
Also add a FIXME to remove code that tricks the tests into passing when the
feature fails to work. Please don't do stuff like this, the tests exist for a
reason!
llvm-svn: 199929
This patch adds the target analysis passes (usually TargetTransformInfo) to the
codgen pipeline. We also expose now the AddAnalysisPasses method through the C
API, because the optimizer passes would also benefit from better target-specific
cost models.
Reviewed by Andrew Kaylor
llvm-svn: 199926
Eliminate the copies LLVM's System mmap and cache invalidation code. These were
slowly drifting away from the original version, and moreover the copied code
was a dead end in terms of portability.
We now statically link to Support but in practice with stripping this adds next
to no weight to the resultant binary.
Also avoid installing lli-child-target to the user's $PATH. It's not meant to
be run directly.
llvm-svn: 199881
Chandler Carruth