scratch/tty-child-frames dfb7f194265 2/2: More workarounds for GDB bug 32313

[Eli Zaretskii]

branch: scratch/tty-child-frames
commit dfb7f1942659cab4464e01f7e498efc4b269de3e
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    More workarounds for GDB bug 32313
    
    * src/eval.c (backtrace_args): Same treatment as
    backtrace_function.
    
    cherry-picked from commit b7b55df.
---
 src/eval.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/eval.c b/src/eval.c
index 874cf6d868c..d0a2abf0089 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -50,8 +50,6 @@ Lisp_Object Vsignaling_function;
 
 /* These would ordinarily be static, but they need to be visible to GDB.  */
 bool backtrace_p (union specbinding *) EXTERNALLY_VISIBLE;
-Lisp_Object *backtrace_args (union specbinding *) EXTERNALLY_VISIBLE;
-Lisp_Object backtrace_function (union specbinding *) EXTERNALLY_VISIBLE;
 union specbinding *backtrace_next (union specbinding *) EXTERNALLY_VISIBLE;
 union specbinding *backtrace_top (void) EXTERNALLY_VISIBLE;
 
@@ -108,12 +106,22 @@ specpdl_arg (union specbinding *pdl)
   return pdl->unwind.arg;
 }
 
-Lisp_Object
-backtrace_function (union specbinding *pdl)
+/* To work around GDB bug 32313
+   <https://sourceware.org/bugzilla/show_bug.cgi?id=32313> make
+   backtrace_* functions visible-to-GDB pointers instead of merely
+   being an externally visible functions themselves.  Declare the
+   pointer first to pacify gcc -Wmissing-variable-declarations.  */
+#define GDB_FUNCPTR(func, resulttype, params) \
+  extern resulttype (*const func) params EXTERNALLY_VISIBLE; \
+  resulttype (*const func) params = func##_body
+
+static Lisp_Object
+backtrace_function_body (union specbinding *pdl)
 {
   eassert (pdl->kind == SPECPDL_BACKTRACE);
   return pdl->bt.function;
 }
+GDB_FUNCPTR (backtrace_function, Lisp_Object, (union specbinding *));
 
 static ptrdiff_t
 backtrace_nargs (union specbinding *pdl)
@@ -122,12 +130,13 @@ backtrace_nargs (union specbinding *pdl)
   return pdl->bt.nargs;
 }
 
-Lisp_Object *
-backtrace_args (union specbinding *pdl)
+static Lisp_Object *
+backtrace_args_body (union specbinding *pdl)
 {
   eassert (pdl->kind == SPECPDL_BACKTRACE);
   return pdl->bt.args;
 }
+GDB_FUNCPTR (backtrace_args, Lisp_Object *, (union specbinding *));
 
 /* Functions to modify slots of backtrace records.  */