sarif-replay: handle relatedLocations without messages (§3.27.22)

Given the .sarif output from e.g.:

  too-many-arguments.c: In function 'test_known_fn':
  too-many-arguments.c:14:3: error: too many arguments to function 'fn_a'; expected 0, have 1
     14 |   fn_a (42);
        |   ^~~~  ~~
  too-many-arguments.c:8:13: note: declared here
      8 | extern void fn_a ();
        |             ^~~~

the underlining of the stray argument (the "42") is captured in
'relatedLocations' (§3.27.22) but previously sarif-replay would not
display this:

  In function 'test_known_fn':
  too-many-arguments.c:14:3: error: too many arguments to function 'fn_a'; expected 0, have 1 [error]
     14 |   fn_a (42);
        |   ^~~~
  too-many-arguments.c:8:13: note: declared here
      8 | extern void fn_a ();
        |             ^~~~

With this patch sarif-replay handles the relatedLocations element as
a secondary location in libgdiagnostics, and correctly underlines
the "42":

  In function 'test_known_fn':
  too-many-arguments.c:14:3: error: too many arguments to function 'fn_a'; expected 0, have 1 [error]
     14 |   fn_a (42);
        |   ^~~~  ~~
  too-many-arguments.c:8:13: note: declared here
      8 | extern void fn_a ();
        |             ^~~~

gcc/ChangeLog:
	* libsarifreplay.cc (sarif_replayer::handle_result_obj): Treat any
	relatedLocations without messages as secondary ranges within the
	diagnostic.  Doing so requires stashing the notes until after
	the diagnostic has been finished, so that relatedLocations can be
	walked in one pass.

gcc/testsuite/ChangeLog:
	* sarif-replay.dg/2.1.0-valid/unlabelled-secondary-locations.sarif:
	New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

2 files changed, 79 insertions, 3 deletions

diff --git a/gcc/libsarifreplay.cc b/gcc/libsarifreplay.cc
index 075dadb..e2d0908 100644
--- a/gcc/libsarifreplay.cc
+++ b/gcc/libsarifreplay.cc
@@ -998,7 +998,6 @@ add_any_annotations (libgdiagnostics::diagnostic &diag,
    - doesn't yet handle "taxa" property (§3.27.8)
    - handling of "level" property (§3.27.10) doesn't yet support the
      full logic for when "level" is absent.
-   - doesn't yet handle "relatedLocations" property (§3.27.22)
    - doesn't yet handle "fixes" property (§3.27.30)
    - doesn't yet support multithreaded flows (§3.36.3)
 */
@@ -1127,9 +1126,9 @@ sarif_replayer::handle_result_obj (const json::object &result_obj,
   add_any_annotations (err, annotations);
   if (path.m_inner)
     err.take_execution_path (std::move (path));
-  err.finish ("%s", text.get ());
 
   // §3.27.22 relatedLocations property
+  std::vector<std::pair<libgdiagnostics::diagnostic, label_text>> notes;
   const property_spec_ref prop_related_locations
     ("result", "relatedLocations", "3.27.22");
   if (auto related_locations_arr
@@ -1172,11 +1171,28 @@ sarif_replayer::handle_result_obj (const json::object &result_obj,
 	      note.set_location (physical_loc);
 	      note.set_logical_location (logical_loc);
 	      add_any_annotations (note, annotations);
-	      note.finish ("%s", text.get ());
+	      notes.push_back ({std::move (note), std::move (text)});
+	    }
+	  else
+	    {
+	      /* Treat related locations without a message as a secondary
+		 range.  */
+	      if (physical_loc.m_inner)
+		err.add_location (physical_loc);
 	    }
 	}
     }
 
+  err.finish ("%s", text.get ());
+
+  // Flush any notes
+  for (auto &iter : notes)
+    {
+      auto &note = iter.first;
+      auto &text = iter.second;
+      note.finish ("%s", text.get ());
+    }
+
   return status::ok;
 
 }
diff --git a/gcc/testsuite/sarif-replay.dg/2.1.0-valid/unlabelled-secondary-locations.sarif b/gcc/testsuite/sarif-replay.dg/2.1.0-valid/unlabelled-secondary-locations.sarif
new file mode 100644
index 0000000..251e2fd
--- /dev/null
+++ b/gcc/testsuite/sarif-replay.dg/2.1.0-valid/unlabelled-secondary-locations.sarif
@@ -0,0 +1,60 @@
+{"$schema": "https://docs.oasis-open.org/sarif/sarif/v2.1.0/errata01/os/schemas/sarif-schema-2.1.0.json",
+ "version": "2.1.0",
+ "runs": [{"tool": {"driver": {"name": "GNU C23",
+                               "fullName": "GNU C23 (GCC) version 15.0.1 20250203 (experimental) (x86_64-pc-linux-gnu)",
+                               "version": "15.0.1 20250203 (experimental)",
+                               "informationUri": "https://gcc.gnu.org/gcc-15/",
+                               "rules": []}},
+           "invocations": [{"executionSuccessful": false,
+                            "toolExecutionNotifications": []}],
+           "originalUriBaseIds": {"PWD": {"uri": "file:///nonexistent/"}},
+           "artifacts": [{"location": {"uri": "too-many-arguments.c",
+                                       "uriBaseId": "PWD"},
+                          "sourceLanguage": "c",
+                          "contents": {"text": "extern void fn_a ();\n\nvoid test_known_fn (void)\n{\n  fn_a (42);\n}\n"},
+                          "roles": ["analysisTarget"]}],
+           "results": [{"ruleId": "error",
+                        "level": "error",
+                        "message": {"text": "too many arguments to function 'fn_a'; expected 0, have 1"},
+                        "locations": [{"physicalLocation": {"artifactLocation": {"uri": "too-many-arguments.c",
+                                                                                 "uriBaseId": "PWD"},
+                                                            "region": {"startLine": 5,
+                                                                       "startColumn": 3,
+                                                                       "endColumn": 7},
+                                                            "contextRegion": {"startLine": 5,
+                                                                              "snippet": {"text": "  fn_a (42);\n"}}},
+                                       "logicalLocations": [{"name": "test_known_fn",
+                                                             "fullyQualifiedName": "test_known_fn",
+                                                             "decoratedName": "test_known_fn",
+                                                             "kind": "function"}],
+                                       "relationships": [{"target": 0,
+                                                          "kinds": ["relevant"]}]}],
+                        "relatedLocations": [{"physicalLocation": {"artifactLocation": {"uri": "too-many-arguments.c",
+                                                                                        "uriBaseId": "PWD"},
+                                                                   "region": {"startLine": 1,
+                                                                              "startColumn": 13,
+                                                                              "endColumn": 17},
+                                                                   "contextRegion": {"startLine": 1,
+                                                                                     "snippet": {"text": "extern void fn_a ();\n"}}},
+                                              "message": {"text": "declared here"},
+                                              "properties": {"nestingLevel": 0}},
+                                             {"physicalLocation": {"artifactLocation": {"uri": "too-many-arguments.c",
+                                                                                        "uriBaseId": "PWD"},
+                                                                   "region": {"startLine": 5,
+                                                                              "startColumn": 9,
+                                                                              "endColumn": 11},
+                                                                   "contextRegion": {"startLine": 5,
+                                                                                     "snippet": {"text": "  fn_a (42);\n"}}},
+                                              "id": 0}]}]}]}
+
+/* Verify that we underline the "42" here.  */
+/* { dg-begin-multiline-output "" }
+In function 'test_known_fn':
+too-many-arguments.c:5:3: error: too many arguments to function 'fn_a'; expected 0, have 1 [error]
+    5 |   fn_a (42);
+      |   ^~~~  ~~
+too-many-arguments.c:1:13: note: declared here
+    1 | extern void fn_a ();
+      |             ^~~~
+   { dg-end-multiline-output "" } */
+// TODO: trailing [error]