* amd64fbsd-tdep.c: Fix sigtramp recognition.

[deliverable/binutils-gdb.git] / gdb / ppc-linux-tdep.c

diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index 5b82a910f332cb2e5ac5af048fecbee8aa1cd04a..3134132345632a79ba598b76ccb8a3c751d2a27d 100644 (file)
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -188,7 +188,7 @@ ppc_linux_in_sigtramp (CORE_ADDR pc, char *func_name)
   return (pc == handler || pc == handler + 4);
 }
 
-static inline int
+static int
 insn_is_sigreturn (unsigned long pcinsn)
 {
   switch(pcinsn)
@@ -731,7 +731,7 @@ insn_ds_field (unsigned int insn)
 }
 
 
-/* If DESC is the address of a 64-bit PowerPC Linux function
+/* If DESC is the address of a 64-bit PowerPC GNU/Linux function
    descriptor, return the descriptor's entry point.  */
 static CORE_ADDR
 ppc64_desc_entry_point (CORE_ADDR desc)
@@ -894,15 +894,38 @@ ppc64_skip_trampoline_code (CORE_ADDR pc)
 }
 
 
-/* On 64-bit PowerPC Linux, the ELF header's e_entry field is the
-   address of a function descriptor for the entry point function, not
-   the actual entry point itself.  So to find the actual address at
-   which execution should begin, we need to fetch the function's entry
-   point from that descriptor.  */
+/* Support for CONVERT_FROM_FUNC_PTR_ADDR(ADDR) on PPC64 GNU/Linux.
+
+   Usually a function pointer's representation is simply the address
+   of the function. On GNU/Linux on the 64-bit PowerPC however, a
+   function pointer is represented by a pointer to a TOC entry. This
+   TOC entry contains three words, the first word is the address of
+   the function, the second word is the TOC pointer (r2), and the
+   third word is the static chain value.  Throughout GDB it is
+   currently assumed that a function pointer contains the address of
+   the function, which is not easy to fix.  In addition, the
+   conversion of a function address to a function pointer would
+   require allocation of a TOC entry in the inferior's memory space,
+   with all its drawbacks.  To be able to call C++ virtual methods in
+   the inferior (which are called via function pointers),
+   find_function_addr uses this function to get the function address
+   from a function pointer.  */
+
+/* Return real function address if ADDR (a function pointer) is in the data
+   space and is therefore a special function pointer.  */
+
 static CORE_ADDR
-ppc64_call_dummy_address (void)
+ppc64_linux_convert_from_func_ptr_addr (CORE_ADDR addr)
 {
-  return ppc64_desc_entry_point (entry_point_address ());
+  struct obj_section *s;
+
+  s = find_pc_section (addr);
+  if (s && s->the_bfd_section->flags & SEC_CODE)
+    return addr;
+
+  /* ADDR is in the data space, so it's a pointer to a descriptor, not
+     the entry point.  */
+  return ppc64_desc_entry_point (addr);
 }
 
 
@@ -1027,7 +1050,10 @@ ppc_linux_init_abi (struct gdbarch_info info,
   
   if (tdep->wordsize == 8)
     {
-      set_gdbarch_call_dummy_address (gdbarch, ppc64_call_dummy_address);
+      /* Handle PPC64 GNU/Linux function pointers (which are really
+         function descriptors).  */
+      set_gdbarch_convert_from_func_ptr_addr
+        (gdbarch, ppc64_linux_convert_from_func_ptr_addr);
 
       set_gdbarch_in_solib_call_trampoline
         (gdbarch, ppc64_in_solib_call_trampoline);