Merge branch 'leo/112-non-instr_dc_warn' into 'master'

Instrument.Common: Do not warn for big BDD in stmt+decision

Closes #112

See merge request eng/cov/gnatcoverage!243

gnatcov emits a warning when encountering a decision with too many
paths to keep track of. This warning is not relevant for decision
coverage as the non instrumentation of the individual conditions
does not affect the accuracy of the coverage report for level
stmt+decision.

This change removes the warning when MC/DC coverage is not enabled.

Closes eng/cov/gnatcoverage#112

Author: leocreuse

testsuite/tests/U416-006-big-bdd/test.py

@@ -14,30 +14,7 @@
 from SUITE.gprutils import GPRswitches
 
 
-tmp = Wdir("tmp_")
-
-gpr = gprfor(mains=["test_eval.adb"], srcdirs=["../src"], langs=["Ada", "C"])
-
-build_run_and_coverage(
-    gprsw=GPRswitches(root_project=gpr),
-    extra_coverage_args=["--annotate=xcov"],
-    covlevel="stmt+mcdc",
-    mains=["test_eval"],
-    trace_mode="src",
-    tolerate_instrument_messages=\
-      "Number of distinct paths .* exceeds the limit",
-)
-
-check_xcov_reports(
-    "*.xcov",
-    expected_cov={
-        "test_eval.adb.xcov": {"+": {11, 13, 19, 20}},
-        "testconditions.adb.xcov": {"?": {17}, "+": {22, 23, 24, 25, 26, 27}},
-        "compute.c.xcov": {"?": {4}, "+": {5, 6}},
-    },
-    cwd="obj",
-)
-
+tmp = Wdir()
 
 def warning_re_for(filename, sloc):
     """
@@ -53,17 +30,64 @@ def warning_re_for(filename, sloc):
     ).format(filename=re.escape(filename), sloc=re.escape(sloc))
 
 
-# The order in which sources are instrumented is not specified, so sort lines
-# in the output of "gnatcov instrument" to get deterministic test execution.
-log = "\n".join(sorted(contents_of("instrument.log").splitlines()))
+def do_one_level(level):
+    tmp.to_subdir(f"tmp_{level}")
+    thistest.log(f"===== {level} =====")
+
+    gpr = gprfor(mains=["test_eval.adb"], srcdirs=["../src"], langs=["Ada", "C"])
+
+    build_run_and_coverage(
+        gprsw=GPRswitches(root_project=gpr),
+        extra_coverage_args=["--annotate=xcov"],
+        covlevel=level,
+        mains=["test_eval"],
+        trace_mode="src",
+        tolerate_instrument_messages=(
+            "Number of distinct paths .* exceeds the limit"
+            if level == "stmt+mcdc"
+            else None
+        ),
+    )
+
+    expected_cov = {
+        "test_eval.adb.xcov": {"+": {11, 13, 19, 20}},
+        "testconditions.adb.xcov": {"+": {22, 23, 24, 25, 26, 27}},
+        "compute.c.xcov": {"+": {5, 6}},
+    }
+
+    # For stmt+decision, the BDD is still computed, but the non-instrumentation
+    # of the conditions has no impact on stmt+decision coverage reports.
+    # As such, we expect no warnings or errors in the log and no undetermined
+    # coverage items in the report.
+
+    if level == "stmt+mcdc":
+        expected_cov["testconditions.adb.xcov"]['?'] = {17}
+        expected_cov["compute.c.xcov"]['?'] = {4}
+    else:
+        expected_cov["testconditions.adb.xcov"]['+'].add(17)
+        expected_cov["compute.c.xcov"]['+'].add(4)
+
+    check_xcov_reports("*.xcov", expected_cov, cwd="obj")
+
+    if level == "stmt+mcdc":
+        # The order in which sources are instrumented is not specified, so sort
+        # lines in the output of "gnatcov instrument" to get deterministic test
+        # execution.
+        log = "\n".join(sorted(contents_of("instrument.log").splitlines()))
+
+        thistest.fail_if_no_match(
+            what="Unexpected/missing warnings for MC/DC path limit",
+            regexp="^" + "\n".join([
+                warning_re_for("compute.c", "4:11"),
+                warning_re_for("testconditions.adb", "17:9"),
+            ]),
+            actual=log,
+        )
+
+# Run the mcdc case
+do_one_level("stmt+mcdc")
 
-thistest.fail_if_no_match(
-    what="Unexpected/missing warnings for MC/DC path limit",
-    regexp="^" + "\n".join([
-        warning_re_for("compute.c", "4:11"),
-        warning_re_for("testconditions.adb", "17:9"),
-    ]),
-    actual=log,
-)
+# Then the decision case
+do_one_level("stmt+decision")
 
 thistest.result()

tools/gnatcov/instrument-common.adb

@@ -201,7 +201,7 @@ package body Instrument.Common is
 
          --  Warn if the number of paths exceeded the limit
 
-         if Path_Count = 0 then
+         if Path_Count = 0 and then Coverage.MCDC_Coverage_Enabled then
             Diagnostics.Report
               (Decision_Sloc,
                "Number of distinct paths in the decision exceeds the limit"