[patch, rfc, 6] Check for "main" in minimal symbols in BT

[Andrew Cagney <ac131313@redhat.com>]

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Hello,

This patch extends the inside_main_func() check so that, when "main" 
isn't found in the symbol table,  the mimimal symbol table is searched. 
  In case you're wondering, the logic for finding the end address of 
"main" was cobbled together from random bits of code from blockframe and 
the alpha.  It certainly appears to work for d10v and i386.

Anyway, with this, the d10v's assembler backtrace stops at main goving 
the short 'n' sharp backtrace

	foo2
	main

instead of the current:

	foo2
	main
	_start
	_start

The patch (since things now stop in "main") also removes the d10v 
specific frame ID eq test; and updates the testsuite so that it doesn't 
allow "_start" in the backtrace.

I intend checking this into both 6.0 branch and mainline in a few days.

comments,
Andrew

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2003-07-07  Andrew Cagney  <cagney@redhat.com>

	* frame.c (get_prev_frame): Add comment about forgetting to check
	the minimal symbol table for "main".
	* blockframe.c (inside_main_func): Look for "main" in the minimal
	symbol table.
	* d10v-tdep.c (d10v_frame_this_id): Delete check that frames are
	identical.

Index: testsuite/ChangeLog
2003-07-07  Andrew Cagney  <cagney@redhat.com>

	* gdb.asm/asm-source.exp: Do not allow "start" in the backtrace.

Index: blockframe.c
===================================================================
RCS file: /cvs/src/src/gdb/blockframe.c,v
retrieving revision 1.72
diff -u -r1.72 blockframe.c
--- blockframe.c	23 May 2003 17:05:19 -0000	1.72
+++ blockframe.c	7 Jul 2003 20:25:21 -0000
@@ -106,6 +106,47 @@
 	    BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
 	}
     }
+
+  /* Not in the normal symbol tables, see if "main" is in the partial
+     symbol table.  If it's not, then give up.  */
+  {
+    struct minimal_symbol *msymbol
+      = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
+    if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_text)
+      {
+	struct obj_section *osect
+	  = find_pc_sect_section (SYMBOL_VALUE_ADDRESS (msymbol),
+				  msymbol->ginfo.bfd_section);
+	if (osect != NULL)
+	  {
+	    int i;
+	    /* Step over other symbols at this same address, and
+	       symbols in other sections, to find the next symbol in
+	       this section with a different address.  */
+	    for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
+	      {
+		if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
+		    && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
+		  break;
+	      }
+
+	    symfile_objfile->ei.main_func_lowpc = SYMBOL_VALUE_ADDRESS (msymbol);
+
+	    /* Use the lesser of the next minimal symbol in the same
+	       section, or the end of the section, as the end of the
+	       function.  */
+	    if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
+		&& SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
+	      symfile_objfile->ei.main_func_highpc = SYMBOL_VALUE_ADDRESS (msymbol + i);
+	    else
+	      /* We got the start address from the last msymbol in the
+		 objfile.  So the end address is the end of the
+		 section.  */
+	      symfile_objfile->ei.main_func_highpc = osect->endaddr;
+	  }
+      }
+  }
+
   return (symfile_objfile->ei.main_func_lowpc <= pc &&
 	  symfile_objfile->ei.main_func_highpc > pc);
 }
Index: d10v-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/d10v-tdep.c,v
retrieving revision 1.127
diff -u -r1.127 d10v-tdep.c
--- d10v-tdep.c	7 Jul 2003 14:36:57 -0000	1.127
+++ d10v-tdep.c	7 Jul 2003 20:25:21 -0000
@@ -1417,15 +1417,6 @@
 
   id = frame_id_build (base, func);
 
-  /* Check that we're not going round in circles with the same frame
-     ID (but avoid applying the test to sentinel frames which do go
-     round in circles).  Can't use frame_id_eq() as that doesn't yet
-     compare the frame's PC value.  */
-  if (frame_relative_level (next_frame) >= 0
-      && get_frame_type (next_frame) != DUMMY_FRAME
-      && frame_id_eq (get_frame_id (next_frame), id))
-    return;
-
   (*this_id) = id;
 }
 
Index: frame.c
===================================================================
RCS file: /cvs/src/src/gdb/frame.c,v
retrieving revision 1.130
diff -u -r1.130 frame.c
--- frame.c	7 Jul 2003 20:07:12 -0000	1.130
+++ frame.c	7 Jul 2003 20:25:22 -0000
@@ -1870,6 +1870,12 @@
      be allowed to unwind.  */
   /* NOTE: cagney/2003-02-25: Don't enable until someone has found
      hard evidence that this is needed.  */
+  /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func - wasn't
+     checking for "main" in the minimal symbols.  With that fixed
+     asm-source tests now stop in "main" instead of halting the
+     backtrace in wierd and wonderful ways.  Suspect that
+     inside_entry_file and inside_entry_func tests were added to work
+     around that (now fixed) case.  */
   if (0
       && this_frame->type != DUMMY_FRAME && this_frame->level >= 0
       && inside_entry_func (get_frame_pc (this_frame)))
Index: testsuite/gdb.asm/asm-source.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.asm/asm-source.exp,v
retrieving revision 1.39
diff -u -r1.39 asm-source.exp
--- testsuite/gdb.asm/asm-source.exp	7 Jul 2003 14:48:50 -0000	1.39
+++ testsuite/gdb.asm/asm-source.exp	7 Jul 2003 20:25:26 -0000
@@ -244,7 +244,7 @@
 # doesn't fall off the stack.
 
 gdb_test "bt 10" \
-	"\#0.*foo2.*asmsrc2\[.\]s:12.*\#1.*main.*asmsrc1\[.\]s:33(.*\#2.*start\[^\r\n\]*)?" \
+	"\#0.*foo2.*asmsrc2\[.\]s:12.*\#1.*main.*asmsrc1\[.\]s:33" \
 	"bt ALL in foo2"
 
 # See if a capped `bt' prints the right source files.