[llvm] r342617 - [XRay][compiler-rt] FDRLogWriter Abstraction

[Dean Michael Berris via llvm-commits]

Author: dberris
Date: Wed Sep 19 22:22:37 2018
New Revision: 342617

URL: http://llvm.org/viewvc/llvm-project?rev=342617&view=rev
Log:
[XRay][compiler-rt] FDRLogWriter Abstraction

Summary:
This change introduces an `FDRLogWriter` type which is responsible for
serialising metadata and function records to character buffers. This is
the first step in a refactoring of the implementation of the FDR runtime
to allow for more granular testing of the individual components of the
implementation.

The main contribution of this change is a means of hiding the details of
how specific records are written to a buffer, and for managing the
extents of these buffers. We make use of C++ features (templates and
some metaprogramming) to reduce repetition in the act of writing out
specific kinds of records to the buffer.

In this process, we make a number of changes across both LLVM and
compiler-rt to allow us to use the `Trace` abstraction defined in the
LLVM project in the testing of the runtime implementation. This gives us
a closer end-to-end test which version-locks the runtime implementation
with the loading implementation in LLVM.

We also allow using gmock in compiler-rt unit tests, by adding the
requisite definitions in the `AddCompilerRT.cmake` module. We also add
the terminfo library detection along with inclusion of the appropriate
compiler flags for header include lookup.

Finally, we've gone ahead and updated the FDR logging implementation to
use the FDRLogWriter for the lowest-level record-writing details.

Following patches will isolate the state machine transitions which
manage the set-up and tear-down of the buffers we're using in multiple
threads.

Reviewers: mboerger, eizan

Subscribers: mgorny, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D52220

Modified:
    llvm/trunk/include/llvm/XRay/Trace.h

Modified: llvm/trunk/include/llvm/XRay/Trace.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/XRay/Trace.h?rev=342617&r1=342616&r2=342617&view=diff
==============================================================================
--- llvm/trunk/include/llvm/XRay/Trace.h (original)
+++ llvm/trunk/include/llvm/XRay/Trace.h Wed Sep 19 22:22:37 2018
@@ -46,20 +46,25 @@ namespace xray {
 ///
 class Trace {
   XRayFileHeader FileHeader;
-  std::vector<XRayRecord> Records;
+  using RecordVector = std::vector<XRayRecord>;
+  RecordVector Records;
 
   typedef std::vector<XRayRecord>::const_iterator citerator;
 
   friend Expected<Trace> loadTrace(const DataExtractor &, bool);
 
 public:
+  using size_type = RecordVector::size_type;
+  using value_type = RecordVector::value_type;
+  using const_iterator = RecordVector::const_iterator;
+
   /// Provides access to the loaded XRay trace file header.
   const XRayFileHeader &getFileHeader() const { return FileHeader; }
 
-  citerator begin() const { return Records.begin(); }
-  citerator end() const { return Records.end(); }
+  const_iterator begin() const { return Records.begin(); }
+  const_iterator end() const { return Records.end(); }
   bool empty() const { return Records.empty(); }
-  size_t size() const { return Records.size(); }
+  size_type size() const { return Records.size(); }
 };
 
 /// This function will attempt to load XRay trace records from the provided