[llvm-cov] Add support for exporting coverage data to JSON

This enables users to export coverage information as portable JSON for use by
analysis tools and storage in document based databases.

The export sub-command is invoked just like the others:

  llvm-cov export -instr-profile path/to/foo.profdata path/to/foo.binary

The resulting JSON contains a list of files and functions. Every file object
contains a list of segments, expansions, and a summary of the file's region,
function, and line coverage. Every function object contains the function's name
and regions. There is also a total summary for the entire object file.

Patch by Eddie Hurtig!

Differential Revision: https://reviews.llvm.org/D22651

llvm-svn: 276813

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/docs/CommandGuide/llvm-cov.rst b/llvm/docs/CommandGuide/llvm-cov.rst
index 946b125a452..665dbcd2113 100644
--- a/llvm/docs/CommandGuide/llvm-cov.rst
+++ b/llvm/docs/CommandGuide/llvm-cov.rst
@@ -24,6 +24,7 @@ COMMANDS
 * :ref:`gcov <llvm-cov-gcov>`
 * :ref:`show <llvm-cov-show>`
 * :ref:`report <llvm-cov-report>`
+* :ref:`export <llvm-cov-export>`
 
 .. program:: llvm-cov gcov
 
@@ -315,3 +316,31 @@ OPTIONS
  It is an error to specify an architecture that is not included in the
  universal binary or to use an architecture that does not match a
  non-universal binary.
+
+EXPORT COMMAND
+--------------
+
+SYNOPSIS
+^^^^^^^^
+
+:program:`llvm-cov export` [*options*] -instr-profile *PROFILE* *BIN*
+
+DESCRIPTION
+^^^^^^^^^^^
+
+The :program:`llvm-cov export` command exports regions, functions, expansions,
+and summaries of the coverage of a binary *BIN* using the profile data
+*PROFILE* as JSON.
+
+For information on compiling programs for coverage and generating profile data,
+see :ref:`llvm-cov-show`.
+
+OPTIONS
+^^^^^^^
+
+.. option:: -arch=<name>
+
+ If the covered binary is a universal binary, select the architecture to use.
+ It is an error to specify an architecture that is not included in the
+ universal binary or to use an architecture that does not match a
+ non-universal binary.