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From: "hluaw at connect dot ust.hk" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug gdb/30315] New: GDB not showing variable that is supposed to be there
Date: Wed, 05 Apr 2023 13:39:26 +0000	[thread overview]
Message-ID: <bug-30315-4717@http.sourceware.org/bugzilla/> (raw)

https://sourceware.org/bugzilla/show_bug.cgi?id=30315

            Bug ID: 30315
           Summary: GDB not showing variable that is supposed to be there
           Product: gdb
           Version: 13.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdb
          Assignee: unassigned at sourceware dot org
          Reporter: hluaw at connect dot ust.hk
  Target Milestone: ---

Given the following code:

#include "stdint.h"
#include "string.h"
#include <stdio.h>
int a, b;
char* c;
static int func_1() {
  int i = 0;
  for (; i < 4; i++)
    ;
  for (; a <= 4;) {
    uint16_t d;
    b = 0;
    return b;
    { int i; }
  }
  return b;
}
int main() {
  func_1();
  printf(c);
}

Compiled with gcc 12.2.0 and -O1 -g

The DWARF says that i persists until func_1 exits

Breakpoint 1, func_1 () at r.c:10
10        for (; a <= 4;) {
(gdb) info addr i
Symbol "i" is multi-location:
  Range 0x40112a-0x40112a: the constant 0
  Range 0x40112a-0x40112a: the constant 1
  Range 0x40112a-0x40112a: the constant 2
  Range 0x40112a-0x40112a: the constant 3
  Range 0x40112a-0x40113d: the constant 4
.
(gdb) p i
$1 = 4

But GDB says i is <optimized out> prematurely at line 12 with $pc = 0x401133
still in the range of func_1

(gdb) p i
$2 = <optimized out>
(gdb) p $pc
$3 = (void (*)()) 0x401133 <main+13>
(gdb)

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             reply	other threads:[~2023-04-05 13:39 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-05 13:39 hluaw at connect dot ust.hk [this message]
2023-04-05 14:36 ` [Bug gdb/30315] " tromey at sourceware dot org
2024-01-20 16:19 ` ssbssa at sourceware dot org
2024-01-20 16:34 ` ssbssa at sourceware dot org

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