From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21456 invoked by alias); 2 May 2007 00:14:46 -0000 Received: (qmail 21439 invoked by uid 22791); 2 May 2007 00:14:45 -0000 X-Spam-Check-By: sourceware.org Received: from mail-out3.apple.com (HELO mail-out3.apple.com) (17.254.13.22) by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 02 May 2007 00:14:41 +0000 Received: from relay7.apple.com (relay7.apple.com [17.128.113.37]) by mail-out3.apple.com (8.13.8/8.13.8) with ESMTP id l420Eed1023522 for ; Tue, 1 May 2007 17:14:40 -0700 (PDT) Received: from relay7.apple.com (unknown [127.0.0.1]) by relay7.apple.com (Symantec Mail Security) with ESMTP id 37690304CB; Tue, 1 May 2007 17:14:40 -0700 (PDT) X-AuditID: 11807125-a2451bb00000097b-2c-4637d7f0216c Received: from [17.201.21.120] (athena.apple.com [17.201.21.120]) by relay7.apple.com (Apple SCV relay) with ESMTP id 1289E30012; Tue, 1 May 2007 17:14:40 -0700 (PDT) Message-Id: <80EE31A6-4DF2-4D1F-B23D-8B814C1E6928@apple.com> From: Caroline Tice To: gdb-patches@sourceware.org Content-Type: multipart/mixed; boundary=Apple-Mail-18-41700492 Mime-Version: 1.0 (Apple Message framework v880) Subject: [PATCH]: Tracking and reporting uninitialized variables Date: Wed, 02 May 2007 00:14:00 -0000 Cc: Caroline Tice X-Mailer: Apple Mail (2.880) Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2007-05/txt/msg00024.txt.bz2 --Apple-Mail-18-41700492 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Content-length: 2206 As part of some work I have been doing on improving debugging of optimized code, I have created a GCC patch that tags variables it believes are uninitialized with a new Dwarf op (an extension), DW_OP_GNU_uninit. I have submitted that patch to the GCC patches list and am waiting for approval to commit it. I have also created the following gdb patch to recognize the new op and inform the user when a variable the user requests to see is uninitialized. I have tested this patch on some small testcases and I have run the gdb dejagnu testsuite with no regressions. I am new to submitting things to this list, so if there is anything else I ought to have done, please let me know (kindly!). Is this patch okay to commit to gdb? -- Caroline Tice ctice@apple.com 2007-05-01 Caroline Tice * c-valprint.c (c_value_print): If the var_status field of the value struct is 0, print out "[uninitialized]" before the value. * dwarf2expr.c (add_piece): Make function non-static. (unsigned_address_type): Likewise. (signed_address_type): Likewise. (execute_stack_op): Initialize ctx->var_status field; allow DW_OP_GNU_uninit as legal op following a DW_OP_reg op or a DW_OP_regx op; add case for DW_OP_GNU_uninit and update ctx->var_status appropriately. * dwarf2expr.h (struct dwarf_expr_context): New field, var_status. (unsigned_address_type): Add extern declaration. (signed_address_type): Likewise. (add_piece): Likewise. * dwarf2loc.c (dwarf2_evaluate_loc_desc): Add call to set_var_status. * dwarf2read.c (dwarf_stack_op_name): Add case for DW_OP_GNU_uninit. (decode_locdesc): Add case for DW_OP_GNU_uninit. * value.c (struct value): New field, var_status. (allocate_value): Initialize new field. (set_var_status): New function. (value_var_status): New function. * value.h (value_var_status): New extern declaration. (set_var_status): Likewise. * include/elf/dwarf2.h: (enum dwarf_location_atom): Add new DW_OP, DW_OP_GNU_uninit. --Apple-Mail-18-41700492 Content-Disposition: attachment; filename=fsf-gdb-patch.txt Content-Type: text/plain; x-unix-mode=0644; name=fsf-gdb-patch.txt Content-Transfer-Encoding: 7bit Content-length: 9486 Index: gdb/c-valprint.c =================================================================== RCS file: /cvs/src/src/gdb/c-valprint.c,v retrieving revision 1.42 diff -c -3 -p -r1.42 c-valprint.c *** gdb/c-valprint.c 26 Jan 2007 20:54:16 -0000 1.42 --- gdb/c-valprint.c 1 May 2007 22:10:43 -0000 *************** c_value_print (struct value *val, struct *** 556,561 **** --- 556,564 ---- } } + if (value_var_status (val) == 0) + fprintf_filtered (stream, " [uninitialized] "); + if (objectprint && (TYPE_CODE (type) == TYPE_CODE_CLASS)) { /* Attempt to determine real type of object */ Index: gdb/dwarf2expr.c =================================================================== RCS file: /cvs/src/src/gdb/dwarf2expr.c,v retrieving revision 1.19 diff -c -3 -p -r1.19 dwarf2expr.c *** gdb/dwarf2expr.c 9 Jan 2007 17:58:50 -0000 1.19 --- gdb/dwarf2expr.c 1 May 2007 22:10:43 -0000 *************** dwarf_expr_fetch (struct dwarf_expr_cont *** 106,112 **** } /* Add a new piece to CTX's piece list. */ ! static void add_piece (struct dwarf_expr_context *ctx, int in_reg, CORE_ADDR value, ULONGEST size) { --- 106,112 ---- } /* Add a new piece to CTX's piece list. */ ! void add_piece (struct dwarf_expr_context *ctx, int in_reg, CORE_ADDR value, ULONGEST size) { *************** dwarf2_read_address (gdb_byte *buf, gdb_ *** 213,219 **** /* Return the type of an address, for unsigned arithmetic. */ ! static struct type * unsigned_address_type (void) { switch (TARGET_ADDR_BIT / TARGET_CHAR_BIT) --- 213,219 ---- /* Return the type of an address, for unsigned arithmetic. */ ! struct type * unsigned_address_type (void) { switch (TARGET_ADDR_BIT / TARGET_CHAR_BIT) *************** unsigned_address_type (void) *** 232,238 **** /* Return the type of an address, for signed arithmetic. */ ! static struct type * signed_address_type (void) { switch (TARGET_ADDR_BIT / TARGET_CHAR_BIT) --- 232,238 ---- /* Return the type of an address, for signed arithmetic. */ ! struct type * signed_address_type (void) { switch (TARGET_ADDR_BIT / TARGET_CHAR_BIT) *************** execute_stack_op (struct dwarf_expr_cont *** 257,262 **** --- 257,263 ---- gdb_byte *op_ptr, gdb_byte *op_end) { ctx->in_reg = 0; + ctx->var_status = 1; /* Default is initialized. */ while (op_ptr < op_end) { *************** execute_stack_op (struct dwarf_expr_cont *** 383,389 **** case DW_OP_reg29: case DW_OP_reg30: case DW_OP_reg31: ! if (op_ptr != op_end && *op_ptr != DW_OP_piece) error (_("DWARF-2 expression error: DW_OP_reg operations must be " "used either alone or in conjuction with DW_OP_piece.")); --- 384,392 ---- case DW_OP_reg29: case DW_OP_reg30: case DW_OP_reg31: ! if (op_ptr != op_end ! && *op_ptr != DW_OP_piece ! && *op_ptr != DW_OP_GNU_uninit) error (_("DWARF-2 expression error: DW_OP_reg operations must be " "used either alone or in conjuction with DW_OP_piece.")); *************** execute_stack_op (struct dwarf_expr_cont *** 394,400 **** case DW_OP_regx: op_ptr = read_uleb128 (op_ptr, op_end, ®); ! if (op_ptr != op_end && *op_ptr != DW_OP_piece) error (_("DWARF-2 expression error: DW_OP_reg operations must be " "used either alone or in conjuction with DW_OP_piece.")); --- 397,405 ---- case DW_OP_regx: op_ptr = read_uleb128 (op_ptr, op_end, ®); ! if (op_ptr != op_end ! && *op_ptr != DW_OP_piece ! && *op_ptr != DW_OP_GNU_uninit) error (_("DWARF-2 expression error: DW_OP_reg operations must be " "used either alone or in conjuction with DW_OP_piece.")); *************** execute_stack_op (struct dwarf_expr_cont *** 704,709 **** --- 709,718 ---- } goto no_push; + case DW_OP_GNU_uninit: + ctx->var_status = 0; + goto no_push; + default: error (_("Unhandled dwarf expression opcode 0x%x"), op); } Index: gdb/dwarf2expr.h =================================================================== RCS file: /cvs/src/src/gdb/dwarf2expr.h,v retrieving revision 1.9 diff -c -3 -p -r1.9 dwarf2expr.h *** gdb/dwarf2expr.h 9 Jan 2007 17:58:50 -0000 1.9 --- gdb/dwarf2expr.h 1 May 2007 22:10:43 -0000 *************** struct dwarf_expr_context *** 76,81 **** --- 76,84 ---- will be on the expression stack. */ int in_reg; + /* Initialization status of variable. */ + int var_status; + /* An array of pieces. PIECES points to its first element; NUM_PIECES is its length. *************** gdb_byte *read_sleb128 (gdb_byte *buf, g *** 135,138 **** --- 138,144 ---- CORE_ADDR dwarf2_read_address (gdb_byte *buf, gdb_byte *buf_end, int *bytes_read); + extern struct type *unsigned_address_type (void); + extern struct type *signed_address_type (void); + extern void add_piece (struct dwarf_expr_context *, int, CORE_ADDR, ULONGEST); #endif /* dwarf2expr.h */ Index: gdb/dwarf2loc.c =================================================================== RCS file: /cvs/src/src/gdb/dwarf2loc.c,v retrieving revision 1.39 diff -c -3 -p -r1.39 dwarf2loc.c *** gdb/dwarf2loc.c 24 Jan 2007 22:04:48 -0000 1.39 --- gdb/dwarf2loc.c 1 May 2007 22:10:43 -0000 *************** dwarf2_evaluate_loc_desc (struct symbol *** 256,261 **** --- 256,263 ---- VALUE_ADDRESS (retval) = address; } + set_var_status (retval, ctx->var_status); + free_dwarf_expr_context (ctx); return retval; Index: gdb/dwarf2read.c =================================================================== RCS file: /cvs/src/src/gdb/dwarf2read.c,v retrieving revision 1.218 diff -c -3 -p -r1.218 dwarf2read.c *** gdb/dwarf2read.c 18 Apr 2007 13:25:04 -0000 1.218 --- gdb/dwarf2read.c 1 May 2007 22:10:44 -0000 *************** dwarf_stack_op_name (unsigned op) *** 8629,8634 **** --- 8629,8636 ---- return "DW_OP_bit_piece"; case DW_OP_GNU_push_tls_address: return "DW_OP_GNU_push_tls_address"; + case DW_OP_GNU_uninit: + return "DW_OP_GNU_uninit"; /* HP extensions. */ case DW_OP_HP_is_value: return "DW_OP_HP_is_value"; *************** decode_locdesc (struct dwarf_block *blk, *** 9204,9209 **** --- 9206,9214 ---- dwarf2_complex_location_expr_complaint (); break; + case DW_OP_GNU_uninit: + break; + default: complaint (&symfile_complaints, _("unsupported stack op: '%s'"), dwarf_stack_op_name (op)); Index: gdb/value.c =================================================================== RCS file: /cvs/src/src/gdb/value.c,v retrieving revision 1.41 diff -c -3 -p -r1.41 value.c *** gdb/value.c 13 Apr 2007 14:17:46 -0000 1.41 --- gdb/value.c 1 May 2007 22:10:44 -0000 *************** struct value *** 157,162 **** --- 157,165 ---- actually exist in the program. */ char optimized_out; + /* If value is a variable, is it initialized or not. */ + int var_status; + /* Actual contents of the value. For use of this value; setting it uses the stuff above. Not valid if lazy is nonzero. Target byte-order. We force it to be aligned properly for any possible *************** allocate_value (struct type *type) *** 232,237 **** --- 235,241 ---- val->embedded_offset = 0; val->pointed_to_offset = 0; val->modifiable = 1; + val->var_status = 1; /* Default to initialized. */ return val; } *************** using_struct_return (struct type *value_ *** 1691,1696 **** --- 1695,1717 ---- != RETURN_VALUE_REGISTER_CONVENTION); } + /* Set the var_status field in a value struct. */ + + void + set_var_status (struct value *val, int status) + { + val->var_status = status; + } + + + /* Return the var_status field in a value struct. */ + + int + value_var_status (struct value *val) + { + return val->var_status; + } + void _initialize_values (void) { Index: gdb/value.h =================================================================== RCS file: /cvs/src/src/gdb/value.h,v retrieving revision 1.96 diff -c -3 -p -r1.96 value.h *** gdb/value.h 9 Jan 2007 17:58:59 -0000 1.96 --- gdb/value.h 1 May 2007 22:10:44 -0000 *************** extern int value_contents_equal (struct *** 193,198 **** --- 193,202 ---- extern int value_optimized_out (struct value *value); extern void set_value_optimized_out (struct value *value, int val); + /* */ + extern int value_var_status (struct value *); + extern void set_var_status (struct value *, int); + /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a single value might have multiple LVALs), this hacked interface is limited to just the first PIECE. Expect further change. */ Index: include/elf/dwarf2.h =================================================================== RCS file: /cvs/src/src/include/elf/dwarf2.h,v retrieving revision 1.19 diff -c -3 -p -r1.19 dwarf2.h *** include/elf/dwarf2.h 2 Mar 2006 00:54:27 -0000 1.19 --- include/elf/dwarf2.h 1 May 2007 22:10:44 -0000 *************** enum dwarf_location_atom *** 540,545 **** --- 540,546 ---- DW_OP_bit_piece = 0x9d, /* GNU extensions. */ DW_OP_GNU_push_tls_address = 0xe0, + DW_OP_GNU_uninit = 0xf0, /* HP extensions. */ DW_OP_HP_unknown = 0xe0, /* Ouch, the same as GNU_push_tls_address. */ DW_OP_HP_is_value = 0xe1, --Apple-Mail-18-41700492--