Summary:
I hadn't realized that instrumentation runs before inlining, so we can't
use the function as the comdat group. Doing so can create relocations
against discarded sections when references to discarded __profc_
variables are inlined into functions outside the function's comdat
group.
In the future, perhaps we should consider standardizing the comdat group
names that ELF and COFF use. It will save object file size, since
__profv_$sym won't appear in the symbol table again.
Reviewers: xur, vsk
Subscribers: eraman, hiraditya, cfe-commits, #sanitizers, llvm-commits
Tags: #clang, #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D58737
llvm-svn: 355044
Summary:
The MS C++ ABI has no constructor variants, but it has destructor
variants, so we should move the deleting destructor variant check
outside the check for "does the ABI have constructor variants".
Fixes PR37561, so basic code coverage works on Windows with C++.
Reviewers: vsk
Subscribers: jdoerfert, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D58691
llvm-svn: 354924
Lifting from Bob Wilson's notes: The hash value that we compute and
store in PGO profile data to detect out-of-date profiles does not
include enough information. This means that many significant changes to
the source will not cause compiler warnings about the profile being out
of date, and worse, we may continue to use the outdated profile data to
make bad optimization decisions. There is some tension here because
some source changes won't affect PGO and we don't want to invalidate the
profile unnecessarily.
This patch adds a new hashing scheme which is more sensitive to loop
nesting, conditions, and out-of-order control flow. Here are examples
which show snippets which get the same hash under the current scheme,
and different hashes under the new scheme:
Loop Nesting Example
--------------------
// Snippet 1
while (foo()) {
while (bar()) {}
}
// Snippet 2
while (foo()) {}
while (bar()) {}
Condition Example
-----------------
// Snippet 1
if (foo())
bar();
baz();
// Snippet 2
if (foo())
bar();
else
baz();
Out-of-order Control Flow Example
---------------------------------
// Snippet 1
while (foo()) {
if (bar()) {}
baz();
}
// Snippet 2
while (foo()) {
if (bar())
continue;
baz();
}
In each of these cases, it's useful to differentiate between the
snippets because swapping their profiles gives bad optimization hints.
The new hashing scheme considers some logical operators in an effort to
detect more changes in conditions. This isn't a perfect scheme. E.g, it
does not produce the same hash for these equivalent snippets:
// Snippet 1
bool c = !a || b;
if (d && e) {}
// Snippet 2
bool f = d && e;
bool c = !a || b;
if (f) {}
This would require an expensive data flow analysis. Short of that, the
new hashing scheme looks reasonably complete, based on a scan over the
statements we place counters on.
Profiles which use the old version of the PGO hash remain valid and can
be used without issue (there are tests in tree which check this).
rdar://17068282
Differential Revision: https://reviews.llvm.org/D39446
llvm-svn: 318229
The root cause of the issues reported in D32406 and D34680 is that clang
instruments functions without bodies. Make it stop doing that, and also
teach it how to use old (incorrectly generated) profiles without
crashing.
llvm-svn: 306883
Clang warns that a profile is out-of-date if it can't find a profile
record for any function in a TU. This warning became noisy after llvm
started allowing dead-stripping of instrumented functions.
To fix this, this patch changes the existing profile out-of-date warning
(-Wprofile-instr-out-of-date) so that it only complains about mismatched
data. Further, it introduces a new, off-by-default warning about missing
function data (-Wprofile-instr-missing).
Differential Revision: https://reviews.llvm.org/D28867
llvm-svn: 301570
2nd attempt: the first was in r296231, but it had a use after lifetime
bug.
Clang has logic to lower certain conditional expressions directly into llvm
select instructions. However, it does not emit the correct profile counter
increment as it does this: it emits an unconditional increment of the counter
for the 'then branch', even if the value selected is from the 'else branch'
(this is PR32019).
That means, given the following snippet, we would report that "0" is selected
twice, and that "1" is never selected:
int f1(int x) {
return x ? 0 : 1;
^2 ^0
}
f1(0);
f1(1);
Fix the problem by using the instrprof_increment_step intrinsic to do the
proper increment.
llvm-svn: 296245
Clang has logic to lower certain conditional expressions directly into
llvm select instructions. However, it does not emit the correct profile
counter increment as it does this: it emits an unconditional increment
of the counter for the 'then branch', even if the value selected is from
the 'else branch' (this is PR32019).
That means, given the following snippet, we would report that "0" is
selected twice, and that "1" is never selected:
int f1(int x) {
return x ? 0 : 1;
^2 ^0
}
f1(0);
f1(1);
Fix the problem by using the instrprof_increment_step intrinsic to do
the proper increment.
llvm-svn: 296231
Fix the fact that we don't assign profile counters to constructors in
classes with virtual bases, or constructors with variadic parameters.
Differential Revision: https://reviews.llvm.org/D30131
llvm-svn: 296062
The cxx-structors.cpp test checks that some instrumentation doesn't
appear, but it should be more explicit about which instrumentation it
actually expects to appear.
llvm-svn: 295532
The frontend can't see "__profn" profile name variables after IRGen
because llvm throws these away now. Tighten up some test cases which
checked for the non-existence of those variables.
llvm-svn: 295528
This is a re-try of r295085: fix up some test cases that assume that
profile name variables are preserved by the instrprof pass.
This catches one additional case in test/CoverageMapping/unused_names.c.
llvm-svn: 295101
Much to my surprise, '-disable-llvm-optzns' which I thought was the
magical flag I wanted to get at the raw LLVM IR coming out of Clang
deosn't do that. It still runs some passes over the IR. I don't want
that, I really want the *raw* IR coming out of Clang and I strongly
suspect everyone else using it is in the same camp.
There is actually a flag that does what I want that I didn't know about
called '-disable-llvm-passes'. I suspect many others don't know about it
either. It both does what I want and is much simpler.
This removes the confusing version and makes that spelling of the flag
an alias for '-disable-llvm-passes'. I've also moved everything in Clang
to use the 'passes' spelling as it seems both more accurate (*all* LLVM
passes are disabled, not just optimizations) and much easier to remember
and spell correctly.
This is part of simplifying how Clang drives LLVM to make it cleaner to
wire up to the new pass manager.
Differential Revision: https://reviews.llvm.org/D28047
llvm-svn: 290392
Value profiling should not profile constants and/or constant
expressions when they appear as callees in call instructions.
Constant expressions form when a direct callee has bitcasts or
inttoptr(ptrtint (callee)) nests surrounding it. Value profiling
should avoid instrumenting such cases. Mostly NFC.
llvm-svn: 265037
For terminator instructions, the value profiling instrumentation
happens in a basic block other than where the value site resides.
This CR moves the instrumentation point prior to the value site.
Mostly NFC.
llvm-svn: 264783
This patch changes cc1 option for PGO profile use from
-fprofile-instr-use=<path> to -fprofile-instrument-use-path=<path>.
-fprofile-instr-use=<path> is now a driver only option.
In addition to decouple the cc1 option from the driver level option, this patch
also enables IR level profile use. cc1 option handling now reads the profile
header and sets CodeGenOpt ProfileUse (valid values are {None, Clang, LLVM}
-- this is a common enum for -fprofile-instrument={}, for the profile
instrumentation), and invoke the pipeline to enable the respective PGO use pass.
Reviewers: silvas, davidxl
Differential Revision: http://reviews.llvm.org/D17737
llvm-svn: 262515
This patch changes cc1 option -fprofile-instr-generate to an enum option
-fprofile-instrument={clang|none}. It also changes cc1 options
-fprofile-instr-generate= to -fprofile-instrument-path=.
The driver level option -fprofile-instr-generate and -fprofile-instr-generate=
remain intact. This change will pave the way to integrate new PGO
instrumentation in IR level.
Review: http://reviews.llvm.org/D16730
llvm-svn: 259811
1. Make test case more focused and robust by focusing on what to be tested (linkage, icall) -- make it easier to validate
2. Testing linkages of data and counter variables instead of names. Counters and data are more relavant to be tested.
llvm-svn: 259067
NFC. These hints are only used for inlining and the inliner now uses
the same criteria to identify hot and cold callees and set appropriate
thresholds without relying on these hints. Hence this removed code is
superfluous.
Differential Revision: http://reviews.llvm.org/D15726
llvm-svn: 256793
This sets the maximum entry count among all functions in the program to the module using module flags. This allows the optimizer to use this information.
Differential Revision: http://reviews.llvm.org/D15163
llvm-svn: 255918
(test case update)
Profile symbols have long prefixes which waste space and creating pressure for linker.
This patch shortens the prefixes to minimal length without losing verbosity.
Differential Revision: http://reviews.llvm.org/D15503
llvm-svn: 255576
(This is part-2 of the patch -- fixing test cases)
Before the patch, -fprofile-instr-generate compile will fail
if no integrated-as is specified when the file contains
any static functions (the -S output is also invalid).
This patch fixed the issue. With the change, the index format
version will be bumped up by 1. Backward compatibility is
preserved with this change.
Differential Revision: http://reviews.llvm.org/D15243
llvm-svn: 255366
Constructors and destructors may be represented by several functions
in IR. Only base structors correspond to source code, others are
small pieces of code and eventually call the base variant. In this
case instrumentation of non-base structors has little sense, this
fix remove it. Now profile data of a declaration corresponds to
exactly one function in IR, it agrees with the current logic of the
profile data loading.
This change fixes PR24996.
Differential Revision: http://reviews.llvm.org/D15158
llvm-svn: 254876
cannot assume that the current working directory is writable in all test
environments. I don't know a better way to write this test of hand, lets
discuss. Possibly, a better option would be to put these together with
other test testing the driver directly.
llvm-svn: 241885
This patch adds support for specifying where the profile is emitted in a
way similar to GCC. These flags are used to specify directories instead
of filenames. When -fprofile-generate=DIR is used, the compiler will
generate code to write to <DIR>/default.profraw.
The patch also adds a couple of extensions: LLVM_PROFILE_FILE can still be
used to override the directory and file name to use and -fprofile-use
accepts both directories and filenames.
To simplify the set of flags used in the backend, all the flags get
canonicalized to -fprofile-instr-{generate,use} when passed to the
backend. The decision to use a default name for the profile is done
in the driver.
llvm-svn: 241825
Several tests wouldn't pass when executed on an armv7a_pc_linux triple
due to the non-default arm_aapcs calling convention produced on the
function definitions in the IR output. Account for this with the
application of a little regex.
Patch by Ying Yi.
llvm-svn: 240971
When a profile file cannot be opened, we used to display just the error
message but not the name of the profile the compiler was trying to open.
This will become useful in the next set of patches that introduce
GCC-compatible flags to specify profiles.
llvm-svn: 240715
-fprofile-instr-generate does not emit counter increment intrinsics
for Dtor_Deleting and Dtor_Complete destructors with assigned
counters. This causes unnecessary [-Wprofile-instr-out-of-date]
warnings during profile-use runs even if the source has never been
modified since profile collection.
Patch by Betul Buyukkurt. Thanks!
llvm-svn: 237804
This change is the third of 3 patches to add support for specifying
the profile output from the command line via -fprofile-instr-generate=<path>,
where the specified output path/file will be overridden by the
LLVM_PROFILE_FILE environment variable.
This patch adds the necessary support to the clang frontend, and adds a
new test.
The compiler-rt and llvm parts are r236055 and r236288, respectively.
Patch by Teresa Johnson. Thanks!
llvm-svn: 236289
We were assigning the counter for the body of the loop to the loop
variable initialization for some reason here, but our tests completely
lacked coverage for range-for loops. This fixes that and makes the
logic generally more similar to the logic for a regular for.
llvm-svn: 236277
Update the test cases to pass when lambda call operators use thiscall.
Update the lambda-to-block conversion operator to use the default free
function calling convention instead of the call operator's convention.
This reverts commit r233082 and re-instates r233023.
llvm-svn: 233835
When we instrument a program for profiling, we copy the linkage of an
instrumented function so that our datastructures merge in the same way
as the function. This avoids redundant copies for things like
linkonce, but ends up emitting names we never need to reference for
normal and internal symbols. Promoting internal and external linkage
to private for these variables reduces the size overhead of profiling
drastically.
llvm-svn: 232799
Most of the checks in these two tests were actually testing the
behaviour of the instrprof LLVM pass. Now that we're testing that
specifically in LLVM's test suite, it's better if we only test the
frontend's behaviour here.
llvm-svn: 230387
We were previously emitting counter increments even if we didn't have
an insertion point, which would result in a CallInst with no
parent. This leads to a crash, as in pr22166, if we try to do
GlobalDCE.
llvm-svn: 225495
The logic for lowering profiling counters has been moved to an LLVM
pass. Emit the intrinsics rather than duplicating the whole pass in
clang.
llvm-svn: 223683
There's no need to use different names for the local variables than we
use in the profile itself, and it's a bit simpler and easier to debug
if we're consistent.
llvm-svn: 223173
We've added support for a multiple functions with the same name in
LLVM's profile data, so the lookup returning the function hash it
found doesn't make sense anymore. Update to pass in the hash we
expect.
This also adds a test that the version 1 format is still readable,
since the new API is expected to handle that.
llvm-svn: 214586
Improve the warning when building with -fprofile-instr-use and a file
appears not to have been profiled at all. This keys on whether a
function is defined in the main file or not to avoid false negatives
when one includes a header with functions that have been profiled.
llvm-svn: 211760
Shared objects are fairly broken for InstrProf right now -- a follow-up
commit in compiler-rt will fix the rest of this.
The main problem here is that at link time, profile data symbols in the
shared object might get used instead of symbols from the main
executable, creating invalid profile data sections.
<rdar://problem/16918688>
llvm-svn: 208939
We don't assign counters for implicit Decls, but we were emitting code
to increment the (non-existent) counters and adding empty counter
lists in the output. This fixes the checks in assignRegionCounters and
emitInstrumentationData to do the right thing, and adds an assert for
the pathological case of emitting zero counters.
llvm-svn: 207203
In preparation for using a binary format for instrumentation based
profiling, explicitly treat the test inputs as text and transform them
before running. This will allow us to leave the checked in files in
human readable format once the instrumentation format is binary.
No functional change.
llvm-svn: 206509
The function hash should change when control flow changes. This patch
hashes the type of each AST node that affects counters, rather than just
counting how many there are. These types are combined into a small
enumerator that currently has 16 values.
The new hash algorithm packs the enums for consecutively visited types
into a `uint64_t`. In order to save space for new types, the types are
assumed to be 6-bit values (instead of 4-bit). In order to minimize
overhead for functions with little control flow, the `uint64_t` is used
directly as a hash if it never fills up; if it does, it's passed through
an MD5 context.
<rdar://problem/16435801>
llvm-svn: 206397
This adds a warning that triggers when profile data doesn't match for
the source that's being compiled with -fprofile-instr-use=. This fires
only once per translation unit, as warning on every mismatched
function would be quite noisy.
llvm-svn: 206322
CapturedStmt was being ignored by instrumentation based profiling, and
its counters attributed to the containing function. Instead, we need
to treat this as a top level entity, like we do with blocks.
llvm-svn: 206231
Until now we were generating duplicate counters for lambdas: one set
in the function where the lambda was declared and another for the
lambda itself. Instead, we should skip over the bodies of lambdas in
their containing contexts.
llvm-svn: 206081
Reid Kleckner