Commit Graph

12 Commits

Author SHA1 Message Date
Rong Xu 9c6f1538cc [PGO] Change profile use cc1 option to handle IR level profiles
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
2016-03-02 20:59:36 +00:00
Saleem Abdulrasool 9e593499b9 test: change argument
This failed on AArch64 due to the type mismatch using int instead of
__builtin_va_list.

llvm-svn: 250112
2015-10-12 21:19:30 +00:00
Justin Bogner 52a6a97d70 test: Give instrumentation based profiling tests their own directory
These tests are logically related, but they're spread about several
different CodeGen directories. Consolidate them in one place to make
them easier to manage.

llvm-svn: 203541
2014-03-11 04:37:49 +00:00
Bob Wilson bd48799c8d PGO: rename profile data files from .pgodata to .profdata.
These tests were added before we had settled on using a .profdata extension
for the profile data files. Renaming them now for consistency.

llvm-svn: 203166
2014-03-06 21:36:04 +00:00
Bob Wilson da1ebedeea PGO: Use the main file name to help distinguish functions with local linkage.
In addition, for all functions, use the name from the llvm::Function to
identify the function in the profile data. Compute that "function name",
including the file name for local functions, once when assigning the PGO
counters and store it in the CodeGenPGO class.

Move the code to add InlineHint and Cold attributes out of StartFunction(),
because the "function name" string isn't available at that point.

llvm-svn: 203075
2014-03-06 04:55:41 +00:00
Bob Wilson 1e3f3bf950 Add a testcase for r202437.
llvm-svn: 202468
2014-02-28 05:57:14 +00:00
Bob Wilson bf854f0f53 Change PGO instrumentation to compute counts in a separate AST traversal.
Previously, we made one traversal of the AST prior to codegen to assign
counters to the ASTs and then propagated the count values during codegen. This
patch now adds a separate AST traversal prior to codegen for the
-fprofile-instr-use option to propagate the count values. The counts are then
saved in a map from which they can be retrieved during codegen.

This new approach has several advantages:

1. It gets rid of a lot of extra PGO-related code that had previously been
added to codegen.

2. It fixes a serious bug. My original implementation (which was mailed to the
list but never committed) used 3 counters for every loop. Justin improved it to
move 2 of those counters into the less-frequently executed breaks and continues,
but that turned out to produce wrong count values in some cases. The solution
requires visiting a loop body before the condition so that the count for the
condition properly includes the break and continue counts. Changing codegen to
visit a loop body first would be a fairly invasive change, but with a separate
AST traversal, it is easy to control the order of traversal. I've added a
testcase (provided by Justin) to make sure this works correctly.

3. It improves the instrumentation overhead, reducing the number of counters for
a loop from 3 to 1. We no longer need dedicated counters for breaks and
continues, since we can just use the propagated count values when visiting
breaks and continues.

To make this work, I needed to make a change to the way we count case
statements, going back to my original approach of not including the fall-through
in the counter values. This was necessary because there isn't always an AST node
that can be used to record the fall-through count. Now case statements are
handled the same as default statements, with the fall-through paths branching
over the counter increments.  While I was at it, I also went back to using this
approach for do-loops -- omitting the fall-through count into the loop body
simplifies some of the calculations and make them behave the same as other
loops. Whenever we start using this instrumentation for coverage, we'll need
to add the fall-through counts into the counter values.

llvm-svn: 201528
2014-02-17 19:21:09 +00:00
Manman Ren f1a6a2d930 PGO: fix a bug in parsing pgo data.
When a function has a single counter, we will offset the pointer by 1 when
parsing the next function. If a function has multiple counters, we are
okay after skipping rest of the counters.

llvm-svn: 201456
2014-02-15 01:29:02 +00:00
Manman Ren 67a28136ad PGO: instrumentation based profiling sets function attributes.
We collect a maximal function count among all functions in the pgo data file.
For functions that are hot, we set its InlineHint attribute. For functions that
are cold, we set its Cold attribute.

We currently treat functions with >= 30% of the maximal function count as hot
and functions with <= 1% of the maximal function count are treated as cold.
These two numbers are from preliminary tuning on SPEC.

This commit should not affect non-PGO builds and should boost performance on
instrumentation based PGO.

llvm-svn: 200874
2014-02-05 20:40:15 +00:00
Justin Bogner be614c735c CodeGen: Fix tracking of PGO counters for the logical or operator
This adds tests for both logical or and for logical and, which was
already correct.

llvm-svn: 199865
2014-01-23 02:54:30 +00:00
Justin Bogner ef512b9929 CodeGen: Initial instrumentation based PGO implementation
llvm-svn: 198640
2014-01-06 22:27:43 +00:00
Nick Lewycky e2367d2508 Add testcase for r148375!
llvm-svn: 148378
2012-01-18 04:28:31 +00:00