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Start the search for a function's prologue by using the current PC - 4. 

This ensures we start from the actual call site, not the return address.
The latter may actually be in the next consecutive function if the current
function has the __noreturn__ attribute and the alignment is Just Right.
This commit is contained in:
scw 2002-09-19 15:47:33 +00:00
parent 89b1e287f7
commit e5b9e76f43
1 changed files with 12 additions and 7 deletions
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19
sys/arch/sh5/sh5/db_trace.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: db_trace.c,v 1.4 2002/09/19 13:04:02 scw Exp $ */
/* $NetBSD: db_trace.c,v 1.5 2002/09/19 15:47:33 scw Exp $ */
/*
* Copyright 2002 Wasabi Systems, Inc.
@ -275,15 +275,20 @@ db_stack_trace_print(db_expr_t addr, int have_addr, db_expr_t count,
(long)tf->if_state.sf_ssr,
(long)tf->if_state.sf_intevt);
} else
if (prev_frame(fp, pc, &nextfp, &nextpc) == 0) {
/*
* Looks like we have to grovel the current function's
* prologue to find out the next PC and FP. Start the
* search from "PC - 4" to ensure we catch the actual
* "blink" instruction which made the call. Without this,
* we can fall foul of tail-calls and functions with
* the "__noreturn__" attribute (depending on alignment,
* we could pick up the symbol for the *next* function
* and, hence, get the wrong prologue).
*/
if (prev_frame(fp, pc - 4, &nextfp, &nextpc) == 0) {
(*pr)("Can't find caller's stack frame.\n");
break;
} else {
/*
* Otherwise, we were able to determine the caller's
* details by grovelling the current function's
* stack frame.
*/
fp = nextfp;
pc = nextpc & ~1;
}