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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200903 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200901 91177308-0d34-0410-b5e6-96231b3b80d8
During DAGCombine visitShiftByConstant assumes that certain binary operations
with only constant operands can always be folded successfully. This is no longer
true when the constant is opaque. This commit fixes visitShiftByConstant by not
performing the optimization for opaque constants. Otherwise we would end up in
an infinite DAGCombine loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200900 91177308-0d34-0410-b5e6-96231b3b80d8
225 is the default value of inline-threshold. This change will make sure
we have the same inlining behavior as prior to r200886.
As Chandler points out, even though we don't have code in our testing
suite that uses cold attribute, there are larger applications that do
use cold attribute.
r200886 + this commit intend to keep the same behavior as prior to r200886.
We can later on tune the inlinecold-threshold.
The main purpose of r200886 is to help performance of instrumentation based
PGO before we actually hook up inliner with analysis passes such as BPI and BFI.
For instrumentation based PGO, we try to increase inlining of hot functions and
reduce inlining of cold functions by setting inlinecold-threshold.
Another option suggested by Chandler is to use a boolean flag that controls
if we should use OptSizeThreshold for cold functions. The default value
of the boolean flag should not change the current behavior. But it gives us
less freedom in controlling inlining of cold functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200898 91177308-0d34-0410-b5e6-96231b3b80d8
This is a nop. doesSectionRequireSymbols is only used from
isSymbolLinkerVisible. isSymbolLinkerVisible only use from ELF was in
if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined())
return false;
if (Symbol.isTemporary())
return false;
If the symbol is a temporary this code returns false and it is irrelevant if
we take the first if or not. If the symbol is not a temporary,
Asm.isSymbolLinkerVisible returns true without ever calling
doesSectionRequireSymbols.
This was an horrible leftover from when support for ELF was first added.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200894 91177308-0d34-0410-b5e6-96231b3b80d8
Ideally only those transform passes that run at -O0 remain enabled,
in reality we get as close as we reasonably can.
Passes are responsible for disabling themselves, it's not the job of
the pass manager to do it for them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200892 91177308-0d34-0410-b5e6-96231b3b80d8
Added command line option inlinecold-threshold to set threshold for inlining
functions with cold attribute. Listen to the cold attribute when it would
decrease the inline threshold.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200886 91177308-0d34-0410-b5e6-96231b3b80d8
Now to copy a string into a BumpPtrAllocator and get a StringRef to the copy:
StringRef myCopy = myStr.copy(myAllocator);
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200885 91177308-0d34-0410-b5e6-96231b3b80d8
find a register.
The idea is to choose a color for the variable that cannot be allocated and
recolor its interferences around. Unlike the current register allocation scheme,
it is allowed to change the color of an already assigned (but maybe not
splittable or spillable) live interval while propagating this change to its
neighbors.
In other word, there are two things that may help finding an available color:
- Already assigned variables (RS_Done) can be recolored to different color.
- The recoloring allows to catch solutions that needs to touch more that just
the neighbors of the current allocated variable.
E.g.,
vA can use {R1, R2 }
vB can use { R2, R3}
vC can use {R1 }
Where vA, vB, and vC cannot be split anymore (they are reloads for instance) and
they all interfere.
vA is assigned R1
vB is assigned R2
vC tries to evict vA but vA is already done.
=> Regular register allocation heuristic fails.
Last chance recoloring kicks in:
vC does as if vA was evicted => vC uses R1.
vC is marked as fixed.
vA needs to find a color.
None are available.
vA cannot evict vC: vC is a fixed virtual register now.
vA does as if vB was evicted => vA uses R2.
vB needs to find a color.
R3 is available.
Recoloring => vC = R1, vA = R2, vB = R3.
<rdar://problem/15947839>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200883 91177308-0d34-0410-b5e6-96231b3b80d8
I think this was just over-eagerness on my part. The analysis results
need to often be non-const because they need to (in some cases at least)
be updated by the transformation pass in order to remain correct. It
also makes lazy analyses (a common case) needlessly annoying to write in
order to make their entire state mutable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200881 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The check performed in the comparator is invalid, as some STL
implementations enforce strict weak ordering by calling the comparator with the
same value. This check was also in a wrong place: the assertion would only fire
when -help was used. The new check is performed each time the category is
registered (we are not going to have thousands of them, so it's fine to do it in
O(N^2)).
Reviewers: jordan_rose
Reviewed By: jordan_rose
CC: cfe-commits, alexmc
Differential Revision: http://llvm-reviews.chandlerc.com/D2699
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200853 91177308-0d34-0410-b5e6-96231b3b80d8
Small code model (and default reloc model) set Reloc::PIC_ in this test,
and PIC is not yet supported in MCJIT for MIPS.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200852 91177308-0d34-0410-b5e6-96231b3b80d8
In Thumb1 mode, bl instruction might be selected for branches between
basic blocks in the function if the offset is greater than 2KB.
However, this might cause SEGV because the destination symbol
is not marked as thumb function and the execution mode will be reset
to ARM mode.
Since we are sure that these symbols are in the same data fragment, we
can simply resolve these local symbols, and don't emit any relocation
information for this bl instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200842 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200820 91177308-0d34-0410-b5e6-96231b3b80d8
ISSUE:
On Ubuntu 12.04 LTS, arc4random is provided by libbsd.so, which is a
transitive dependency of libedit. If a system had libedit on it that
was implemented in terms of libbsd.so, then the arc4random test,
previously implemented as a linker test, would succeed with -ledit.
However, on Ubuntu this would also require a #include <bsd/stdlib.h>.
This caused a build breakage on configure-based Ubuntu 12.04 with
libedit installed.
FIX:
This fix changes configure to test for arc4random by searching for it
in the standard header files. On Ubuntu 12.04, this test now properly
fails to find arc4random as it is not defined in the default header
locations. It also tweaks the #define names to match the output of the
header check command, which is slightly different than the linker
function check #defines.
I tested the following scenarios:
(1) Ubuntu 12.04 without the libedit package [did not find arc4random,
as expected]
(2) Ubuntu 12.04 with libedit package [properly did not find
arc4random, as expected]
(3) Ubuntu 12.04 with most recent libedit, custom built, and not
dependent on libbsd.so [properly did not find arc4random, as
expected].
(4) FreeBSD 10.0B1 [properly found arc4random, as expected]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200819 91177308-0d34-0410-b5e6-96231b3b80d8
CMake won't expand the dependency graph for us if the dependencies are in
another project, which leads to link errors in the standalone build.
This is a refinement of r200765.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200812 91177308-0d34-0410-b5e6-96231b3b80d8
r200744 moved this into cmake/config-ix.cmake, so that it would happen very
early in the build process. However, standalone builds of Clang and other
external projects never include this file (which is correct).
Now, -stdlib=libc++ and the LLVM_COMPILER_IS_GCC_COMPATIBLE option are
both set in a new include file, HandleLLVMStdlib, which is included by
both config-ix.cmake and HandleLLVMOptions.cmake. This preserves existing
behavior for projects relying on HandleLLVMOptions and still does the
right thing for builds of LLVM itself.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200811 91177308-0d34-0410-b5e6-96231b3b80d8
In file included from ../unittests/Support/ProcessTest.cpp:11:
../utils/unittest/googletest/include/gtest/gtest.h:1448:28: warning: comparison of integers of different signs: 'const unsigned int' and 'const int' [-Wsign-compare]
GTEST_IMPL_CMP_HELPER_(NE, !=);
~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
../utils/unittest/googletest/include/gtest/gtest.h:1433:12: note: expanded from macro 'GTEST_IMPL_CMP_HELPER_'
if (val1 op val2) {\
^
../unittests/Support/ProcessTest.cpp:46:3: note: in instantiation of function template specialization 'testing::internal::CmpHelperNE<unsigned int, int>' requested here
EXPECT_NE((r1 | r2), 0);
^
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200801 91177308-0d34-0410-b5e6-96231b3b80d8
Commuting the 231 and 132 variants would swap addends and
multiplicands/multipliers, which isn't valid.
I'm still trying to reduce a decent test case for this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200792 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200789 91177308-0d34-0410-b5e6-96231b3b80d8
