Add --coverage option for local.py, make clang coverage builds use -fcoverage-mapping/-fprofile-instr-generate

build/config/compiler/BUILD.gn

@@ -536,7 +536,18 @@ config("fuzzing_default") {
 }
 
 config("coverage") {
-  cflags = [ "--coverage" ]
+  if (is_clang) {
+    cflags = [
+      # CLANG builds use the clang-specific coverage, so that versions of lcov/gcov
+      # do not have to match and `llvm-cov export -format=lcov` can be used
+      #
+      # Documentation: https://clang.llvm.org/docs/SourceBasedCodeCoverage.html
+      "-fprofile-instr-generate",
+      "-fcoverage-mapping",
+    ]
+  } else {
+    cflags = [ "--coverage" ]
+  }
   ldflags = cflags
 }
 

scripts/build/build/targets.py

@@ -186,8 +186,7 @@ def BuildHostTarget():
         "-clang").ExceptIfRe('-libfuzzer')
     target.AppendModifier("pw-fuzztest", fuzzing_type=HostFuzzingType.PW_FUZZTEST).OnlyIfRe(
         "-clang").ExceptIfRe('-(libfuzzer|ossfuzz|asan)')
-    target.AppendModifier('coverage', use_coverage=True).OnlyIfRe(
-        '-(chip-tool|all-clusters|tests)')
+    target.AppendModifier('coverage', use_coverage=True)
     target.AppendModifier('dmalloc', use_dmalloc=True)
     target.AppendModifier('clang', use_clang=True)
     target.AppendModifier('test', extra_tests=True)