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[Bug gdb/17036] New: breakpoint reported on wrong line number
- From: "dje at google dot com" <sourceware-bugzilla at sourceware dot org>
- To: gdb-prs at sourceware dot org
- Date: Fri, 06 Jun 2014 21:31:06 +0000
- Subject: [Bug gdb/17036] New: breakpoint reported on wrong line number
- Auto-submitted: auto-generated
https://sourceware.org/bugzilla/show_bug.cgi?id=17036
Bug ID: 17036
Summary: breakpoint reported on wrong line number
Product: gdb
Version: HEAD
Status: NEW
Severity: normal
Priority: P2
Component: gdb
Assignee: unassigned at sourceware dot org
Reporter: dje at google dot com
If one sets a breakpoint on a line with no debug information, the breakpoint
gets set on the next line, but reported to the user as the line he requested.
This is confusing.
(gdb) break x.cc:8
Breakpoint 1 at 0x400633: file x.cc, line 8.
but 0x400633 really corresponds to line 9, not line 8. It should print
"Breakpoint 1 at 0x400633: file x.cc, line 9."
(gdb) run
Starting program: /tmp/x
Breakpoint 1, main () at x.cc:9
9 g();
Testcase:
void g() {}
int f(int, int) { return 1; }
int main(void) {
int i = 0, j = 0;
if (f(i,
j))
g();
}
Line number table, compiled with clang:
Line Number Statements:
Extended opcode 2: set Address to 0x4005d0
Copy
Set prologue_end to true
Special opcode 61: advance Address by 4 to 0x4005d4 and Line by 0 to 1
Special opcode 175: advance Address by 12 to 0x4005e0 and Line by 2 to 3
Set prologue_end to true
Special opcode 215: advance Address by 15 to 0x4005ef and Line by 0 to 3
Advance PC by constant 17 to 0x400600
Special opcode 7: advance Address by 0 to 0x400600 and Line by 2 to 5
Set prologue_end to true
Special opcode 216: advance Address by 15 to 0x40060f and Line by 1 to 6
Special opcode 202: advance Address by 14 to 0x40061d and Line by 1 to 7
Advance PC by constant 17 to 0x40062e
Special opcode 77: advance Address by 5 to 0x400633 and Line by 2 to 9
Special opcode 76: advance Address by 5 to 0x400638 and Line by 1 to 10
Advance PC by 9 to 0x400641
Extended opcode 1: End of Sequence
disas /m, easier to read:
(gdb) disas /m
Dump of assembler code for function main():
5 int main(void) {
0x0000000000400600 <+0>: push %rbp
0x0000000000400601 <+1>: mov %rsp,%rbp
0x0000000000400604 <+4>: sub $0x10,%rsp
0x0000000000400608 <+8>: movl $0x0,-0x4(%rbp)
6 int i = 0, j = 0;
0x000000000040060f <+15>: movl $0x0,-0x8(%rbp)
0x0000000000400616 <+22>: movl $0x0,-0xc(%rbp)
7 if (f(i,
0x000000000040061d <+29>: mov -0x8(%rbp),%edi
0x0000000000400620 <+32>: mov -0xc(%rbp),%esi
0x0000000000400623 <+35>: callq 0x4005e0 <f(int, int)>
0x0000000000400628 <+40>: cmp $0x0,%eax
0x000000000040062d <+45>: je 0x400638 <main()+56>
8 j))
9 g();
0x0000000000400633 <+51>: callq 0x4005d0 <g()>
10 }
0x0000000000400638 <+56>: mov -0x4(%rbp),%eax
0x000000000040063b <+59>: add $0x10,%rsp
0x000000000040063f <+63>: pop %rbp
0x0000000000400640 <+64>: retq
End of assembler dump.
google ref# 15455856
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