For the supplied example, the current development gcc generates
incorrect line number information for one instruction from the inlined
subroutine. The Fedora Core 3 gcc, which identifies itself as "gcc
version 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)", generates correct line
information.
Environment:
System: Linux toadfish.ninemoons.com 2.6.9-1.681_FC3.stk16 #1 Mon Nov 22
16:44:32 EST 2004 i686 i686 i386 GNU/Linux
Architecture: i686
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: /src/sourceware/gcc/gcc/configure -v
--prefix=/opt/local/sourceware
--with-gcc-version-trigger=/src/sourceware/gcc/gcc/gcc/version.c
--enable-languages=c,c++
How-To-Repeat:
For the follow code:
/* 1 */ int add2 (int a, int b)
/* 2 */ {
/* 3 */ return (a + b);
/* 4 */ }
/* 5 */
/* 6 */ inline int add3 (int a, int b, int c)
/* 7 */ {
/* 8 */ return (a + add2 (b , c));
/* 9 */ }
/* 10 */
/* 11 */ main ()
/* 12 */ {
/* 13 */ printf ("%d\n", add3 (2, 3, 4));
/* 14 */ }
Run:
gcc -g -O2 --save-temps -o t t.c
readelf --debug-dump t >t.dwarf
objdump --disassemble t >t.dis
There relevant line table entries from t.dwarf are:
Special opcode 36: advance Address by 2 to 0x80483a0 and Line by 3 to 12
Special opcode 15: advance Address by 1 to 0x80483a1 and Line by -4 to 8
Special opcode 79: advance Address by 5 to 0x80483a6 and Line by 4 to 12
Special opcode 75: advance Address by 5 to 0x80483ab and Line by 0 to 12
Special opcode 85: advance Address by 6 to 0x80483b1 and Line by -4 to 8
Special opcode 234: advance Address by 16 to 0x80483c1 and Line by 5 to 13
Advance PC by constant 17 to 0x80483d2
Special opcode 34: advance Address by 2 to 0x80483d4 and Line by 1 to 14
Advance PC by 2 to 80483d6
I've annotated the disassembly of main() with the line numbers given by
the above entries:
12 080483a0 <main>:
12 80483a0: 55 push %ebp
8 80483a1: b8 04 00 00 00 mov $0x4,%eax
12 80483a6: 89 e5 mov %esp,%ebp
12 80483a8: 83 ec 08 sub $0x8,%esp
12 80483ab: 83 e4 f0 and $0xfffffff0,%esp
12 80483ae: 83 ec 10 sub $0x10,%esp
8 80483b1: 89 44 24 04 mov %eax,0x4(%esp)
8 80483b5: c7 04 24 03 00 00 00 movl $0x3,(%esp)
8 80483bc: e8 af ff ff ff call 8048370 <add2>
13 80483c1: c7 04 24 c8 84 04 08 movl $0x80484c8,(%esp)
** 13 80483c8: 83 c0 02 add $0x2,%eax
13 80483cb: 89 44 24 04 mov %eax,0x4(%esp)
13 80483cf: e8 dc fe ff ff call 80482b0 <[EMAIL
PROTECTED]>
14 80483d4: c9 leave
14 80483d5: c3 ret
The "add $0x2,%eax" instruction, marked with '**', is supposed to be at
line 8, not line 13.
If you go through the same exercise with the Fedora Core 3 compiler, it does
correctly identify this instruction as being at line 8.
--
Summary: Current development gcc generates incorrect line info
for example code
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: fnf at specifixinc dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19192
