Inlined subroutine with loop misses part of PC range in debug info #156700
Description
When the following is compiled...
#include <stdlib.h>
#include <string.h>
struct cmd_struct {
const char *cmd;
};
extern struct cmd_struct commands[];
static struct cmd_struct *get_builtin(const char *s) {
int i;
for (i = 0; i < 20; i++) {
struct cmd_struct *p = commands + i;
if (!strcmp(s, p->cmd))
return p;
}
return NULL;
}
void handle_builtin(int argc, const char **argv) {
struct cmd_struct *builtin;
builtin = get_builtin(argv[0]);
if (builtin)
exit(1);
}
...using Clang 20 at -O1, we see that get_builtin is inlined into handle_builtin, but the debug info for the inlined instance of get_builtin misses an instruction from it's PC range:
0x00000096: DW_TAG_inlined_subroutine
DW_AT_abstract_origin (0x00000027 "get_builtin")
DW_AT_low_pc (0x0000000000000023)
DW_AT_high_pc (0x0000000000000048)
DW_AT_call_file ("/app/example.c")
DW_AT_call_line (22)
DW_AT_call_column (13)
The mov instruction at 0x20 is part of the loop within get_builtin, but for some reason, it is not part of the PC range in the debug info (DW_AT_low_pc says 0x23 instead of 0x20).
Example available on Compiler Explorer