[GCChecker] report FunctionDecl and type for missing JL_NOTSAFEPOINT calls (#46834)

In C++, some calls are implicit, which makes the call alone ambiguous
and the message unclear. This helps clarify it.

Author: vtjnash

Make.inc

@@ -1373,7 +1373,6 @@ CLANGSA_FLAGS :=
 CLANGSA_CXXFLAGS :=
 ifeq ($(OS), Darwin) # on new XCode, the files are hidden
 CLANGSA_FLAGS += -isysroot $(shell xcode-select -p)/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
-CLANGSA_CXXFLAGS += -isystem $(shell xcode-select -p)/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1
 endif
 ifeq ($(USEGCC),1)
 # try to help clang find the c++ files for CC by guessing the value for --prefix

src/clangsa/GCChecker.cpp

@@ -53,8 +53,8 @@ class GCChecker
           check::Location> {
   mutable std::unique_ptr<BugType> BT;
   template <typename callback>
-  void report_error(callback f, CheckerContext &C, const char *message) const;
-  void report_error(CheckerContext &C, const char *message) const {
+  void report_error(callback f, CheckerContext &C, StringRef message) const;
+  void report_error(CheckerContext &C, StringRef message) const {
     return report_error([](PathSensitiveBugReport *) {}, C, message);
   }
   void
@@ -509,7 +509,7 @@ PDP GCChecker::GCValueBugVisitor::VisitNode(const ExplodedNode *N,
 
 template <typename callback>
 void GCChecker::report_error(callback f, CheckerContext &C,
-                             const char *message) const {
+                             StringRef message) const {
   // Generate an error node.
   ExplodedNode *N = C.generateErrorNode();
   if (!N)
@@ -1230,8 +1230,15 @@ void GCChecker::checkPreCall(const CallEvent &Call, CheckerContext &C) const {
     // We could separate out "not safepoint, except for noreturn functions",
     // but that seems like a lot of effort with little benefit.
     if (!FD || !FD->isNoReturn()) {
-      report_error(C, "Calling potential safepoint from function annotated "
-                      "JL_NOTSAFEPOINT");
+      report_error(
+          [&](PathSensitiveBugReport *Report) {
+            if (FD)
+              Report->addNote(
+                  "Tried to call method defined here",
+                  PathDiagnosticLocation::create(FD, C.getSourceManager()));
+          },
+          C, ("Calling potential safepoint as " +
+              Call.getKindAsString() + " from function annotated JL_NOTSAFEPOINT").str());
       return;
     }
   }

test/clangsa/GCPushPop.cpp

@@ -3,6 +3,7 @@
 // RUN: clang -D__clang_gcanalyzer__ --analyze -Xanalyzer -analyzer-output=text -Xclang -load -Xclang libGCCheckerPlugin%shlibext -Xclang -verify -I%julia_home/src -I%julia_home/src/support -I%julia_home/usr/include ${CLANGSA_FLAGS} ${CPPFLAGS} ${CFLAGS} -Xclang -analyzer-checker=core,julia.GCChecker --analyzer-no-default-checks -x c++ %s
 
 #include "julia.h"
+#include <string>
 
 void missingPop() {
   jl_value_t *x = NULL;
@@ -34,3 +35,22 @@ void jl_gc_run_finalizers_in_list(jl_ptls_t ptls, arraylist_t *list)
     //    run_finalizer(ptls, items[i], items[i + 1]);
     JL_GC_POP();
 }
+
+void safepoint(void);
+bool testfunc1() JL_NOTSAFEPOINT
+{
+    struct implied_struct1 { // expected-note{{Tried to call method defined here}}
+        std::string s;
+        struct implied_constructor { } x;
+    } x; // expected-warning{{Calling potential safepoint as CXXConstructorCall from function annotated JL_NOTSAFEPOINT}}
+         // expected-note@-1{{Calling potential safepoint as CXXConstructorCall from function annotated JL_NOTSAFEPOINT}}
+    return 1;
+}
+bool testfunc2() JL_NOTSAFEPOINT
+{
+    struct implied_struct2 { // expected-note{{Tried to call method defined here}}
+        std::string s;
+    } x{""};
+    return 1; // expected-warning{{Calling potential safepoint as CXXDestructorCall from function annotated JL_NOTSAFEPOINT}}
+              // expected-note@-1{{Calling potential safepoint as CXXDestructorCall from function annotated JL_NOTSAFEPOINT}}
+}