FileCheck: fix a bug with multiple --check-prefix options.

Summary:
This fixes a subtle bug in new FileCheck feature added
in r194343. When we search for the first satisfying check-prefix,
we should actually return the first encounter of some check-prefix as a
substring, even if it's not a part of valid check-line. Otherwise
"FileCheck --check-prefix=FOO --check-prefix=BAR" with check file:

  FOO not a vaild check-line
  FOO: foo
  BAR: bar

incorrectly accepted file:

  fog
  bar

as it skipped the first two encounters of FOO, matching only BAR: line.

Reviewers: arsenm, dsanders

Reviewed By: dsanders

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2166

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194565 91177308-0d34-0410-b5e6-96231b3b80d8
SampleProfileLoader pass. Initial setup.

This adds a new scalar pass that reads a file with samples generated
by 'perf' during runtime. The samples read from the profile are
incorporated and emmited as IR metadata reflecting that profile.

The profile file is assumed to have been generated by an external
profile source. The profile information is converted into IR metadata,
which is later used by the analysis routines to estimate block
frequencies, edge weights and other related data.

External profile information files have no fixed format, each profiler
is free to define its own. This includes both the on-disk representation
of the profile and the kind of profile information stored in the file.
A common kind of profile is based on sampling (e.g., perf), which
essentially counts how many times each line of the program has been
executed during the run.

The SampleProfileLoader pass is organized as a scalar transformation.
On startup, it reads the file given in -sample-profile-file to
determine what kind of profile it contains.  This file is assumed to
contain profile information for the whole application. The profile
data in the file is read and incorporated into the internal state of
the corresponding profiler.

To facilitate testing, I've organized the profilers to support two file
formats: text and native. The native format is whatever on-disk
representation the profiler wants to support, I think this will mostly
be bitcode files, but it could be anything the profiler wants to
support. To do this, every profiler must implement the
SampleProfile::loadNative() function.

The text format is mostly meant for debugging. Records are separated by
newlines, but each profiler is free to interpret records as it sees fit.
Profilers must implement the SampleProfile::loadText() function.

Finally, the pass will call SampleProfile::emitAnnotations() for each
function in the current translation unit. This function needs to
translate the loaded profile into IR metadata, which the analyzer will
later be able to use.

This patch implements the first steps towards the above design. I've
implemented a sample-based flat profiler. The format of the profile is
fairly simplistic. Each sampled function contains a list of relative
line locations (from the start of the function) together with a count
representing how many samples were collected at that line during
execution. I generate this profile using perf and a separate converter
tool.

Currently, I have only implemented a text format for these profiles. I
am interested in initial feedback to the whole approach before I send
the other parts of the implementation for review.

This patch implements:

- The SampleProfileLoader pass.
- The base ExternalProfile class with the core interface.
- A SampleProfile sub-class using the above interface. The profiler
  generates branch weight metadata on every branch instructions that
  matches the profiles.
- A text loader class to assist the implementation of
  SampleProfile::loadText().
- Basic unit tests for the pass.

Additionally, the patch uses profile information to compute branch
weights based on instruction samples.

This patch converts instruction samples into branch weights. It
does a fairly simplistic conversion:

Given a multi-way branch instruction, it calculates the weight of
each branch based on the maximum sample count gathered from each
target basic block.

Note that this assignment of branch weights is somewhat lossy and can be
misleading. If a basic block has more than one incoming branch, all the
incoming branches will get the same weight. In reality, it may be that
only one of them is the most heavily taken branch.

I will adjust this assignment in subsequent patches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194566 91177308-0d34-0410-b5e6-96231b3b80d8
Fix -Wdelete-non-virtual-dtor warnings by making SampleProfile methods non-virtual

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194568 91177308-0d34-0410-b5e6-96231b3b80d8
Support for microMIPS trap instruction with immediate operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194569 91177308-0d34-0410-b5e6-96231b3b80d8
Fix bug in .gpword directive parsing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194570 91177308-0d34-0410-b5e6-96231b3b80d8
Don't call doFinalization from verifyFunction.

verifyFunction needs to call doInitialization to collect metadata and avoid
crashing when verifying debug info in a function.

But it should not call doFinalization since that is where the verifier will
check declarations, variables and aliases, which is not desirable when one
only wants to verify a function.

A possible cleanup would be to split the class into a ModuleVerifier and
FunctionVerifier.

Issue reported by Ilia Filippov. Patch by Michael Kruse.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194574 91177308-0d34-0410-b5e6-96231b3b80d8
Remove AllowQuotesInName and friends from MCAsmInfo.

Accepting quotes is a property of an assembler, not of an object file. For
example, ELF can support any names for sections and symbols, but the gnu
assembler only accepts quotes in some contexts and llvm-mc in a few more.

LLVM should not produce different symbols based on a guess about which assembler
will be reading the code it is printing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194575 91177308-0d34-0410-b5e6-96231b3b80d8
FileCheck: fix matching of one check-prefix is a prefix of another

Summary:
Fix a case when "FileCheck --check-prefix=CHECK --check-prefix=CHECKER"
would silently ignore check-lines of the form:
  CHECKER: foo

Reviewers: dsanders

Reviewed By: dsanders

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2168

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194577 91177308-0d34-0410-b5e6-96231b3b80d8
Make sure LLVMLoadLibraryPermanently gets an extern "C" symbol.

Otherwise it's impossible to use it. Also don't include C++ headers in
a C header.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194581 91177308-0d34-0410-b5e6-96231b3b80d8
Move Delinearization pass into an anonymous namespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194582 91177308-0d34-0410-b5e6-96231b3b80d8