tests: Add llvm-cov option and run target for code coverage

Code coverage can be requested with -Dllvm_cov and run with ninja
llvm-cov-tests or llvm-cov-cli.

BUG=b:187647884
BRANCH=None
TEST=meson test; ninja llvm-cov-tests
TEST=ran test_build.sh with coverage enabled
TEST=jenkins ran test_build.sh with coverage disabled

Change-Id: Id6c73bff46e7b88d425956a80def97082b201f56
Signed-off-by: Evan Benn <evanbenn@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/69268
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>

Documentation/building.md

@@ -63,12 +63,9 @@ ninja -C buildcov coverage
 #### llvm
 https://clang.llvm.org/docs/SourceBasedCodeCoverage.html
 ```
-env CFLAGS="-fprofile-instr-generate -fcoverage-mapping" CC=clang meson setup buildclangcov
-env LLVM_PROFILE_FILE=default.profraw ninja -C buildclangcov test
-cd buildclangcov
-llvm-profdata merge -sparse default.profraw -o default.profdata
-llvm-cov show ./flashrom_unit_tests -instr-profile=default.profdata --format=html --output-dir=.
-open index.html
+env CC=clang meson setup buildclangcov -Dllvm_cov=enabled
+ninja -C buildclangcov test
+ninja -C buildclangcov llvm-cov-tests
 ```
 
 ## System specific information

meson.build

@@ -45,6 +45,7 @@ config_default_programmer_name = get_option('default_programmer_name')
 config_default_programmer_args = get_option('default_programmer_args')
 
 cargs = []
+link_args = []
 deps = []
 srcs = files(
   '82802ab.c',
@@ -539,6 +540,11 @@ endif
 
 cargs += '-DCONFIG_DEFAULT_PROGRAMMER_ARGS="' + config_default_programmer_args + '"'
 
+if get_option('llvm_cov').enabled()
+  cargs += ['-fprofile-instr-generate', '-fcoverage-mapping']
+  link_args += ['-fprofile-instr-generate', '-fcoverage-mapping']
+endif
+
 install_headers([
     'include/libflashrom.h',
   ],
@@ -567,7 +573,7 @@ libflashrom = both_libraries(
     cargs,
   ],
   install : true,
-  link_args : vflag,
+  link_args : link_args + [vflag],
   link_depends : mapfile,
 )
 
@@ -601,7 +607,7 @@ configure_file(
 )
 
 if get_option('classic_cli').auto() or get_option('classic_cli').enabled()
-  executable(
+  classic_cli = executable(
     'flashrom',
     files(
       'cli_classic.c',
@@ -612,8 +618,12 @@ if get_option('classic_cli').auto() or get_option('classic_cli').enabled()
     include_directories : include_dir,
     install : true,
     install_dir : get_option('sbindir'),
+    link_args : link_args,
     link_with : libflashrom.get_static_lib(), # flashrom needs internal symbols of libflashrom
   )
+  if get_option('llvm_cov').enabled()
+    run_target('llvm-cov-cli', command : ['scripts/llvm-cov', classic_cli])
+  endif
 endif
 
 if get_option('ich_descriptors_tool').auto() or get_option('ich_descriptors_tool').enabled()

meson_options.txt

@@ -16,3 +16,4 @@ option('programmer', type : 'array', value : ['auto'], choices : [
         'pickit2_spi', 'pony_spi', 'raiden_debug_spi', 'rayer_spi', 'realtek_mst_i2c_spi', 'satamv',
         'satasii', 'serprog',  'stlinkv3_spi', 'usbblaster_spi',
 ], description: 'Active programmers')
+option('llvm_cov', type : 'feature', value : 'disabled', description : 'build for llvm code coverage')

scripts/llvm-cov

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+cd "${MESON_BUILD_ROOT}"
+llvm-profdata merge -sparse default.profraw -o default.profdata
+llvm-cov show -instr-profile=default.profdata -format=html -output-dir=. "$@"
+echo "file://${MESON_BUILD_ROOT}/index.html"

tests/meson.build

@@ -121,7 +121,11 @@ flashrom_tests = executable('flashrom_unit_tests',
     '-U_FORTIFY_SOURCE',
   ],
   export_dynamic : true,
-  link_args : mocks,
+  link_args : mocks + link_args,
   dependencies : [cmocka_dep, flashrom_test_dep],
 )
 test('cmocka test flashrom', flashrom_tests)
+
+if get_option('llvm_cov').enabled()
+  run_target('llvm-cov-tests', command : ['../scripts/llvm-cov', flashrom_tests])
+endif