On 1/20/21 5:00 PM, Jan Hubicka wrote:
There are two thinks that I would like to discuss first
1) I think the option is stil used for value profiling of divisors
It's not. Right now the only usage lives in get_nth_most_common_value which
is an entry point being used for stringops, indirect call and divmod histograms.
2) it is not clear to me how the new counter establishes
reproducibility for indiect calls that have more than 32 targets during
the train run.
We cannot ensure, but I would say that it's very unlikely to happen.
In case of Firefox, there are definitely other reasons why the build is not
reproducible.
I would expect arc counters to differ in between multiple training runs.
If it's really a problem we can come up with other approaches:
- GCOV run-time control over # of tracked values (32 right now)
- similarly we can save more values in .gcda files
I'm sending updated version of the patch.
Martin
>From ffbd2fe90dd3bfceecfeefb679572ca2f6b5f333 Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Tue, 19 Jan 2021 15:43:31 +0100
Subject: [PATCH] Drop profile reproducibility flag as it is not used.
gcc/ChangeLog:
PR gcov-profile/98739
* common.opt: Drop -fprofile-reproducibility flag.
* coretypes.h (enum profile_reproducibility): Drop the enum.
* doc/invoke.texi: Remove documentation.
* value-prof.c (get_nth_most_common_value): Drop usage of
flag_profile_reproducible.
---
gcc/common.opt | 16 ++--------------
gcc/coretypes.h | 7 -------
gcc/doc/invoke.texi | 30 ------------------------------
gcc/value-prof.c | 15 +++------------
4 files changed, 5 insertions(+), 63 deletions(-)
diff --git a/gcc/common.opt b/gcc/common.opt
index bde1711870d..863e9681aea 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2236,21 +2236,9 @@ fprofile-exclude-files=
Common Joined RejectNegative Var(flag_profile_exclude_files)
Instrument only functions from files whose name does not match any of the regular expressions (separated by semi-colons).
-Enum
-Name(profile_reproducibility) Type(enum profile_reproducibility) UnknownError(unknown profile reproducibility method %qs)
-
-EnumValue
-Enum(profile_reproducibility) String(serial) Value(PROFILE_REPRODUCIBILITY_SERIAL)
-
-EnumValue
-Enum(profile_reproducibility) String(parallel-runs) Value(PROFILE_REPRODUCIBILITY_PARALLEL_RUNS)
-
-EnumValue
-Enum(profile_reproducibility) String(multithreaded) Value(PROFILE_REPRODUCIBILITY_MULTITHREADED)
-
fprofile-reproducible
-Common Joined RejectNegative Var(flag_profile_reproducible) Enum(profile_reproducibility) Init(PROFILE_REPRODUCIBILITY_SERIAL)
--fprofile-reproducible=[serial|parallel-runs|multithreaded] Control level of reproducibility of profile gathered by -fprofile-generate.
+Common Ignore Joined RejectNegative
+Does nothing. Preserved for backward compatibility.
Enum
Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
diff --git a/gcc/coretypes.h b/gcc/coretypes.h
index 406572e947d..3a67061a483 100644
--- a/gcc/coretypes.h
+++ b/gcc/coretypes.h
@@ -212,13 +212,6 @@ enum profile_update {
PROFILE_UPDATE_PREFER_ATOMIC
};
-/* Type of profile reproducibility methods. */
-enum profile_reproducibility {
- PROFILE_REPRODUCIBILITY_SERIAL,
- PROFILE_REPRODUCIBILITY_PARALLEL_RUNS,
- PROFILE_REPRODUCIBILITY_MULTITHREADED
-};
-
/* Type of -fstack-protector-*. */
enum stack_protector {
SPCT_FLAG_DEFAULT = 1,
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 5f4a06625eb..c66ba2a62ad 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -582,7 +582,6 @@ Objective-C and Objective-C++ Dialects}.
-fprofile-note=@var{path} -fprofile-prefix-path=@var{path} @gol
-fprofile-update=@var{method} -fprofile-filter-files=@var{regex} @gol
-fprofile-exclude-files=@var{regex} @gol
--fprofile-reproducible=@r{[}multithreaded@r{|}parallel-runs@r{|}serial@r{]} @gol
-fsanitize=@var{style} -fsanitize-recover -fsanitize-recover=@var{style} @gol
-fasan-shadow-offset=@var{number} -fsanitize-sections=@var{s1},@var{s2},... @gol
-fsanitize-undefined-trap-on-error -fbounds-check @gol
@@ -14640,35 +14639,6 @@ any of the regular expressions (separated by semi-colons).
For example, @option{-fprofile-exclude-files=/usr/.*} will prevent instrumentation
of all files that are located in the @file{/usr/} folder.
-@item -fprofile-reproducible=@r{[}multithreaded@r{|}parallel-runs@r{|}serial@r{]}
-@opindex fprofile-reproducible
-Control level of reproducibility of profile gathered by
-@code{-fprofile-generate}. This makes it possible to rebuild program
-with same outcome which is useful, for example, for distribution
-packages.
-
-With @option{-fprofile-reproducible=serial} the profile gathered by
-@option{-fprofile-generate} is reproducible provided the trained program
-behaves the same at each invocation of the train run, it is not
-multi-threaded and profile data streaming is always done in the same
-order. Note that profile streaming happens at the end of program run but
-also before @code{fork} function is invoked.
-
-Note that it is quite common that execution counts of some part of
-programs depends, for example, on length of temporary file names or
-memory space randomization (that may affect hash-table collision rate).
-Such non-reproducible part of programs may be annotated by
-@code{no_instrument_function} function attribute. @command{gcov-dump} with
-@option{-l} can be used to dump gathered data and verify that they are
-indeed reproducible.
-
-With @option{-fprofile-reproducible=parallel-runs} collected profile
-stays reproducible regardless the order of streaming of the data into
-gcda files. This setting makes it possible to run multiple instances of
-instrumented program in parallel (such as with @code{make -j}). This
-reduces quality of gathered data, in particular of indirect call
-profiling.
-
@item -fsanitize=address
@opindex fsanitize=address
Enable AddressSanitizer, a fast memory error detector.
diff --git a/gcc/value-prof.c b/gcc/value-prof.c
index 4c916f4994f..1b174006941 100644
--- a/gcc/value-prof.c
+++ b/gcc/value-prof.c
@@ -745,13 +745,10 @@ gimple_divmod_fixed_value (gassign *stmt, tree value, profile_probability prob,
Counters have the following meaning.
- abs (counters[0]) is the number of executions
+ counters[0] is the number of executions
for i in 0 ... TOPN-1
counters[2 * i + 1] is target
- abs (counters[2 * i + 2]) is corresponding hitrate counter.
-
- Value of counters[0] negative when counter became
- full during merging and some values are lost. */
+ counters[2 * i + 2] is corresponding hitrate counter. */
bool
get_nth_most_common_value (gimple *stmt, const char *counter_type,
@@ -765,17 +762,11 @@ get_nth_most_common_value (gimple *stmt, const char *counter_type,
*count = 0;
*value = 0;
- gcov_type read_all = abs_hwi (hist->hvalue.counters[0]);
+ gcov_type read_all = hist->hvalue.counters[0];
gcov_type v = hist->hvalue.counters[2 * n + 2];
gcov_type c = hist->hvalue.counters[2 * n + 3];
- if (hist->hvalue.counters[0] < 0
- && (flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS
- || (flag_profile_reproducible
- == PROFILE_REPRODUCIBILITY_MULTITHREADED)))
- return false;
-
/* Indirect calls can't be verified. */
if (stmt
&& check_counter (stmt, counter_type, &c, &read_all,
--
2.30.0
