PR middle-end/51696: display indirect function calls properly for trans-mem

[Aldy Hernandez]

For the following testcase, we display indirect calls as memory 
addresses, which can confuse the user:

struct list {
  void (*compare)();
} *listPtr;
static void (*compare)();
__attribute__((transaction_safe))
static void func () {
    listPtr->compare();
/* ^^^^^^^^^^^^^^^^^^^^^^^^^^ */
/* error: unsafe function call ‘<Uf3c0>’.... */
    compare();
}
This happens because pp_c_tree_decl_identifier() dumps the memory 
address when there is no DECL_NAME associated with the symbol.

Instead of displaying something like <Uf3c0> in this particular error, 
perhaps we can display "unsafe indirect function call...".

OK?
        PR middle-end/51696
        * trans-mem.c (diagnose_tm_1): Display indirect calls with no name
        correctly.

Index: testsuite/gcc.dg/tm/pr51696.c
===================================================================
--- testsuite/gcc.dg/tm/pr51696.c       (revision 0)
+++ testsuite/gcc.dg/tm/pr51696.c       (revision 0)
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-fgnu-tm" } */
+
+struct list {
+  void (*compare)();
+} *listPtr;
+
+static void (*compare)();
+
+__attribute__((transaction_safe))
+static void func () {
+  listPtr->compare(); /* { dg-error "unsafe indirect function call" } */
+  compare(); /* { dg-error "unsafe function call" } */
+}
Index: trans-mem.c
===================================================================
--- trans-mem.c (revision 182848)
+++ trans-mem.c (working copy)
@@ -664,9 +664,16 @@ diagnose_tm_1 (gimple_stmt_iterator *gsi
                                "unsafe function call %qD within "
                                "atomic transaction", fn);
                    else
-                     error_at (gimple_location (stmt),
-                               "unsafe function call %qE within "
-                               "atomic transaction", fn);
+                     {
+                       if (DECL_NAME (fn))
+                         error_at (gimple_location (stmt),
+                                   "unsafe function call %qE within "
+                                   "atomic transaction", fn);
+                       else
+                         error_at (gimple_location (stmt),
+                                   "unsafe indirect function call within "
+                                   "atomic transaction", fn);
+                     }
                  }
                else
                  {
@@ -675,9 +682,16 @@ diagnose_tm_1 (gimple_stmt_iterator *gsi
                                "unsafe function call %qD within "
                                "%<transaction_safe%> function", fn);
                    else
-                     error_at (gimple_location (stmt),
-                               "unsafe function call %qE within "
-                               "%<transaction_safe%> function", fn);
+                     {
+                       if (DECL_NAME (fn))
+                         error_at (gimple_location (stmt),
+                                   "unsafe function call %qE within "
+                                   "%<transaction_safe%> function", fn);
+                       else
+                         error_at (gimple_location (stmt),
+                                   "unsafe indirect function call within "
+                                   "%<transaction_safe%> function", fn);
+                     }
                  }
              }
          }