[PGO] Value profiling support

This change introduces an instrumentation intrinsic instruction for
value profiling purposes, the lowering of the instrumentation intrinsic
and raw reader updates. The raw profile data files for llvm-profdata
testing are updated.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253484 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 49 insertions, 0 deletions

diff --git a/docs/LangRef.rst b/docs/LangRef.rst
index cafc208ba8d..709b154e3da 100644
--- a/docs/LangRef.rst
+++ b/docs/LangRef.rst
@@ -9514,6 +9514,55 @@ structures and the code to increment the appropriate value, in a
 format that can be written out by a compiler runtime and consumed via
 the ``llvm-profdata`` tool.
 
+'``llvm.instrprof_value_profile``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare void @llvm.instrprof_value_profile(i8* <name>, i64 <hash>,
+                                                 i64 <value>, i32 <value_kind>,
+                                                 i32 <index>)
+
+Overview:
+"""""""""
+
+The '``llvm.instrprof_value_profile``' intrinsic can be emitted by a
+frontend for use with instrumentation based profiling. This will be
+lowered by the ``-instrprof`` pass to find out the target values,
+instrumented expressions take in a program at runtime.
+
+Arguments:
+""""""""""
+
+The first argument is a pointer to a global variable containing the
+name of the entity being instrumented. ``name`` should generally be the
+(mangled) function name for a set of counters.
+
+The second argument is a hash value that can be used by the consumer
+of the profile data to detect changes to the instrumented source. It
+is an error if ``hash`` differs between two instances of
+``llvm.instrprof_*`` that refer to the same name.
+
+The third argument is the value of the expression being profiled. The profiled
+expression's value should be representable as an unsigned 64-bit value. The
+fourth argument represents the kind of value profiling that is being done. The
+supported value profiling kinds are enumerated through the
+``InstrProfValueKind`` type declared in the
+``<include/llvm/ProfileData/InstrProf.h>`` header file. The last argument is the
+index of the instrumented expression within ``name``. It should be >= 0.
+
+Semantics:
+""""""""""
+
+This intrinsic represents the point where a call to a runtime routine
+should be inserted for value profiling of target expressions. ``-instrprof``
+pass will generate the appropriate data structures and replace the
+``llvm.instrprof_value_profile`` intrinsic with the call to the profile
+runtime library with proper arguments.
+
 Standard C Library Intrinsics
 -----------------------------