From 911b97867b72226df7cfab95374a6c2b89d9ffa3 Mon Sep 17 00:00:00 2001
From: Cristian Morales Vega <cristian@samknows.com>
Date: Tue, 23 Apr 2019 17:12:11 +0100
Subject: CTestCoverageCollectGCOV: run gcov only once

Running gcov once per .gcda file is not only inefficient, it also
generates wrong data since .gcov files can get overwritten and in
general gcov works with less information.

fakegcov.cmake needs to be able to handle multiple .gcda files for the
test to be meaningful.
---
 Modules/CTestCoverageCollectGCOV.cmake        | 38 +++++++++++----------------
 Tests/CTestCoverageCollectGCOV/fakegcov.cmake | 21 ++++++++-------
 2 files changed, 28 insertions(+), 31 deletions(-)

diff --git a/Modules/CTestCoverageCollectGCOV.cmake b/Modules/CTestCoverageCollectGCOV.cmake
index 2258271..8b029ee 100644
--- a/Modules/CTestCoverageCollectGCOV.cmake
+++ b/Modules/CTestCoverageCollectGCOV.cmake
@@ -95,7 +95,7 @@ function(ctest_coverage_collect_gcov)
   set(gcda_files)
   set(label_files)
   if (GCOV_GLOB)
-      file(GLOB_RECURSE gfiles RELATIVE ${binary_dir} "${binary_dir}/*.gcda")
+      file(GLOB_RECURSE gfiles "${binary_dir}/*.gcda")
       list(LENGTH gfiles len)
       # if we have gcda files then also grab the labels file for that target
       if(${len} GREATER 0)
@@ -109,7 +109,7 @@ function(ctest_coverage_collect_gcov)
     file(STRINGS "${binary_dir}/CMakeFiles/TargetDirectories.txt" target_dirs
          ENCODING UTF-8)
     foreach(target_dir ${target_dirs})
-      file(GLOB_RECURSE gfiles RELATIVE ${binary_dir} "${target_dir}/*.gcda")
+      file(GLOB_RECURSE gfiles "${target_dir}/*.gcda")
       list(LENGTH gfiles len)
       # if we have gcda files then also grab the labels file for that target
       if(${len} GREATER 0)
@@ -132,27 +132,21 @@ function(ctest_coverage_collect_gcov)
   # setup the dir for the coverage files
   set(coverage_dir "${binary_dir}/Testing/CoverageInfo")
   file(MAKE_DIRECTORY  "${coverage_dir}")
-  # call gcov on each .gcda file
-  foreach (gcda_file ${gcda_files})
-    # get the directory of the gcda file
-    get_filename_component(gcda_file ${binary_dir}/${gcda_file} ABSOLUTE)
-    get_filename_component(gcov_dir ${gcda_file} DIRECTORY)
-    # run gcov, this will produce the .gcov file in the current
-    # working directory
-    if(NOT DEFINED GCOV_GCOV_OPTIONS)
-      set(GCOV_GCOV_OPTIONS -b)
-    endif()
-    execute_process(COMMAND
-      ${gcov_command} ${GCOV_GCOV_OPTIONS} -o ${gcov_dir} ${gcda_file}
-      OUTPUT_VARIABLE out
-      RESULT_VARIABLE res
-      WORKING_DIRECTORY ${coverage_dir})
-
-    if (GCOV_DELETE)
-      file(REMOVE ${gcda_file})
-    endif()
+  # run gcov, this will produce the .gcov files in the current
+  # working directory
+  if(NOT DEFINED GCOV_GCOV_OPTIONS)
+    set(GCOV_GCOV_OPTIONS -b)
+  endif()
+  execute_process(COMMAND
+    ${gcov_command} ${GCOV_GCOV_OPTIONS} ${gcda_files}
+    OUTPUT_VARIABLE out
+    RESULT_VARIABLE res
+    WORKING_DIRECTORY ${coverage_dir})
+
+  if (GCOV_DELETE)
+    file(REMOVE ${gcda_files})
+  endif()
 
-  endforeach()
   if(NOT "${res}" EQUAL 0)
     if (NOT GCOV_QUIET)
       message(STATUS "Error running gcov: ${res} ${out}")
diff --git a/Tests/CTestCoverageCollectGCOV/fakegcov.cmake b/Tests/CTestCoverageCollectGCOV/fakegcov.cmake
index b0c3a9b..6df4292 100644
--- a/Tests/CTestCoverageCollectGCOV/fakegcov.cmake
+++ b/Tests/CTestCoverageCollectGCOV/fakegcov.cmake
@@ -1,14 +1,17 @@
+function(create_gcov_file gcda_full_path)
+  get_filename_component(gcda_name ${gcda_full_path} NAME)
+  string(REPLACE ".gcda" ".gcov" gcov_name "${gcda_name}")
+
+  file(STRINGS "${gcda_full_path}" source_file LIMIT_COUNT 1 ENCODING UTF-8)
+
+  file(WRITE "${CMAKE_SOURCE_DIR}/${gcov_name}"
+    "        -:    0:Source:${source_file}"
+  )
+endfunction()
+
 foreach(I RANGE 0 ${CMAKE_ARGC})
   if("${CMAKE_ARGV${I}}" MATCHES ".*\\.gcda")
     set(gcda_file "${CMAKE_ARGV${I}}")
+    create_gcov_file(${gcda_file})
   endif()
 endforeach()
-
-get_filename_component(gcda_name ${gcda_file} NAME)
-string(REPLACE ".gcda" ".gcov" gcov_name "${gcda_name}")
-
-file(STRINGS "${gcda_file}" source_file LIMIT_COUNT 1 ENCODING UTF-8)
-
-file(WRITE "${CMAKE_SOURCE_DIR}/${gcov_name}"
-  "        -:    0:Source:${source_file}"
-)
-- 
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