2013-03-05 Jakub Jelinek PR debug/56510 * cfgexpand.c (avoid_complex_debug_insns): New function. (expand_debug_locations): Call it. * gcc.dg/pr56510.c: New test. --- gcc/cfgexpand.c.jj 2013-01-25 21:02:47.000000000 +0100 +++ gcc/cfgexpand.c 2013-03-05 14:32:38.076308346 +0100 @@ -3704,6 +3704,54 @@ expand_debug_source_expr (tree exp) return op0; } +/* Ensure INSN_VAR_LOCATION_LOC (insn) doesn't have unbound complexity. + Allow 4 levels of rtl nesting for most rtl codes, and if we see anything + deeper than that, create DEBUG_EXPRs and emit DEBUG_INSNs before INSN. */ + +static void +avoid_complex_debug_insns (rtx insn, rtx *exp_p, int depth) +{ + rtx exp = *exp_p; + if (exp == NULL_RTX) + return; + if ((OBJECT_P (exp) && !MEM_P (exp)) || GET_CODE (exp) == CLOBBER) + return; + + if (depth == 4) + { + /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */ + rtx dval = make_debug_expr_from_rtl (exp); + + /* Emit a debug bind insn before INSN. */ + rtx bind = gen_rtx_VAR_LOCATION (GET_MODE (exp), + DEBUG_EXPR_TREE_DECL (dval), exp, + VAR_INIT_STATUS_INITIALIZED); + + emit_debug_insn_before (bind, insn); + *exp_p = dval; + return; + } + + const char *format_ptr = GET_RTX_FORMAT (GET_CODE (exp)); + int i, j; + for (i = 0; i < GET_RTX_LENGTH (GET_CODE (exp)); i++) + switch (*format_ptr++) + { + case 'e': + avoid_complex_debug_insns (insn, &XEXP (exp, i), depth + 1); + break; + + case 'E': + case 'V': + for (j = 0; j < XVECLEN (exp, i); j++) + avoid_complex_debug_insns (insn, &XVECEXP (exp, i, j), depth + 1); + break; + + default: + break; + } +} + /* Expand the _LOCs in debug insns. We run this after expanding all regular insns, so that any variables referenced in the function will have their DECL_RTLs set. */ @@ -3724,7 +3772,7 @@ expand_debug_locations (void) if (DEBUG_INSN_P (insn)) { tree value = (tree)INSN_VAR_LOCATION_LOC (insn); - rtx val; + rtx val, prev_insn, insn2; enum machine_mode mode; if (value == NULL_TREE) @@ -3753,6 +3801,9 @@ expand_debug_locations (void) } INSN_VAR_LOCATION_LOC (insn) = val; + prev_insn = PREV_INSN (insn); + for (insn2 = insn; insn2 != prev_insn; insn2 = PREV_INSN (insn2)) + avoid_complex_debug_insns (insn2, &INSN_VAR_LOCATION_LOC (insn2), 0); } flag_strict_aliasing = save_strict_alias; --- gcc/testsuite/gcc.dg/pr56510.c.jj 2013-03-05 14:34:32.600807432 +0100 +++ gcc/testsuite/gcc.dg/pr56510.c 2013-03-05 14:36:01.324412449 +0100 @@ -0,0 +1,37 @@ +/* PR debug/56510 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -g" } */ + +struct S { unsigned long s1; void **s2[0]; }; +void **a, **b, **c, **d, **e, **f; + +static void ** +baz (long x, long y) +{ + void **s = f; + *f = (void **) (y << 8 | (x & 0xff)); + f += y + 1; + return s; +} + +void bar (void); +void +foo (void) +{ + void **g = b[4]; + a = b[2]; + b = b[1]; + g[2] = e; + void **h + = ((void **************************) + a)[1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][1][66]; + void **i = ((struct S *) h)->s2[4]; + d = baz (4, 3); + d[1] = b; + d[2] = a; + d[3] = bar; + b = d; + g[1] = i[2]; + a = g; + ((void (*) (void)) (i[1])) (); +}