src/gdb ChangeLog ada-lang.c testsuite/ChangeL ...

[brobecke at sourceware dot org]

CVSROOT:	/cvs/src
Module name:	src
Changes by:	brobecke@sourceware.org	2012-02-29 19:46:48

Modified files:
	gdb            : ChangeLog ada-lang.c 
	gdb/testsuite  : ChangeLog 
Added files:
	gdb/testsuite/gdb.ada: tagged_not_init.exp 
	gdb/testsuite/gdb.ada/tagged_not_init: foo.adb pck.adb pck.ads 

Log message:
	[Ada] avoid error message pollution with uninitialized tagged variable
	
	Consider the following function...
	
	3 procedure Foo is
	4    I : Integer := Ident (10);
	5    Obj : Base;
	6 begin
	7    Obj.X := I;
	8    Do_Nothing (Obj.X'Address);
	9 end Foo;
	
	... where type "Base" is defined as a plain tagged record. If the user
	stops execution before "Obj" gets initialized (for example, by inserting
	a breakpoint "on" the function - or in other words, by inserting a
	breakpoint using the function name as the location), one might get
	the following of output if you try printing the value of obj:
	
	(gdb) p obj
	object size is larger than varsize-limit
	object size is larger than varsize-limit
	object size is larger than varsize-limit
	$1 = object size is larger than varsize-limit
	(x => 4204154)
	
	Same thing with "info locals":
	
	(gdb) info locals
	i = 0
	obj = object size is larger than varsize-limit
	(x => 4204154)
	
	We have also seen different error messages such as "Cannot read
	memory at 0x...".
	
	The error happens because we are trying to read the dispatch table
	of a tagged type variable before it gets initialized.  So the errors
	might legitimately occur, and are supposed to be be contained.
	However, the way things are written in ada-lang.c:ada_tag_name,
	although the exception is in fact contained, the error message still
	gets to be printed out.
	
	This patch prevents this from happening by eliminating the use of
	catch_errors, and using a TRY_CATCH block instead.  Doing this removed
	the need to use functions specifically fitted for catch_errors, and
	thus some other simplifications could me made.  In the end, the code
	got reorganized a bit to better show the logic behind it, as well as
	the common patterns.
	
	gdb/ChangeLog:
	
	* ada-lang.c (struct tag_args): Delete.
	(ada_get_tsd_type): Function body moved up in source file.
	(ada_tag_name_1, ada_tag_name_2): Delete.
	(ada_get_tsd_from_tag): New function.
	(ada_tag_name_from_tsd): New function.
	(ada_tag_name): Use a TRY_CATCH block instead of catch_errors
	to determine the tag name.
	
	gdb/testsuite/ChangeLog:
	
	* gdb.ada/tagged_not_init: New testcase.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/ChangeLog.diff?cvsroot=src&r1=1.13887&r2=1.13888
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/ada-lang.c.diff?cvsroot=src&r1=1.344&r2=1.345
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/ChangeLog.diff?cvsroot=src&r1=1.3104&r2=1.3105
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.ada/tagged_not_init.exp.diff?cvsroot=src&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.ada/tagged_not_init/foo.adb.diff?cvsroot=src&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.ada/tagged_not_init/pck.adb.diff?cvsroot=src&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/testsuite/gdb.ada/tagged_not_init/pck.ads.diff?cvsroot=src&r1=NONE&r2=1.1