2013-01-30 Jakub Jelinek <jakub@redhat.com>
PR debug/56154
* dwarf2out.c (dwarf2_debug_hooks): Set end_function hook to
dwarf2out_end_function.
(in_first_function_p, maybe_at_text_label_p,
first_loclabel_num_not_at_text_label): New variables.
(dwarf2out_var_location): In the first function find out
lowest loclabel_num N where .LVLN is known not to be equal
to .Ltext0.
(find_empty_loc_ranges_at_text_label, dwarf2out_end_function): New
functions.
* gcc.dg/guality/pr56154-1.c: New test.
* gcc.dg/guality/pr56154-2.c: New test.
* gcc.dg/guality/pr56154-3.c: New test.
* gcc.dg/guality/pr56154-4.c: New test.
* gcc.dg/guality/pr56154-aux.c: New file.
--- gcc/dwarf2out.c.jj 2013-01-11 09:02:48.000000000 +0100
+++ gcc/dwarf2out.c 2013-01-30 16:18:58.362552894 +0100
@@ -2351,6 +2351,7 @@ static void dwarf2out_imported_module_or
static void dwarf2out_abstract_function (tree);
static void dwarf2out_var_location (rtx);
static void dwarf2out_begin_function (tree);
+static void dwarf2out_end_function (unsigned int);
static void dwarf2out_set_name (tree, tree);
/* The debug hooks structure. */
@@ -2378,7 +2379,7 @@ const struct gcc_debug_hooks dwarf2_debu
#endif
dwarf2out_end_epilogue,
dwarf2out_begin_function,
- debug_nothing_int, /* end_function */
+ dwarf2out_end_function, /* end_function */
dwarf2out_function_decl, /* function_decl */
dwarf2out_global_decl,
dwarf2out_type_decl, /* type_decl */
@@ -20627,6 +20628,14 @@ dwarf2out_set_name (tree decl, tree name
add_name_attribute (die, dname);
}
+/* True if before or during processing of the first function being emitted. */
+static bool in_first_function_p = true;
+/* True if loc_note during dwarf2out_var_location call might still be
+ before first real instruction at address equal to .Ltext0. */
+static bool maybe_at_text_label_p = true;
+/* One above highest N where .LVLN label might be equal to .Ltext0 label. */
+static unsigned int first_loclabel_num_not_at_text_label;
+
/* Called by the final INSN scan whenever we see a var location. We
use it to drop labels in the right places, and throw the location in
our lookup table. */
@@ -20734,6 +20743,45 @@ dwarf2out_var_location (rtx loc_note)
ASM_OUTPUT_DEBUG_LABEL (asm_out_file, "LVL", loclabel_num);
loclabel_num++;
last_label = ggc_strdup (loclabel);
+ /* See if loclabel might be equal to .Ltext0. If yes,
+ bump first_loclabel_num_not_at_text_label. */
+ if (!have_multiple_function_sections
+ && in_first_function_p
+ && maybe_at_text_label_p)
+ {
+ static rtx last_start;
+ rtx insn;
+ for (insn = loc_note; insn; insn = previous_insn (insn))
+ if (insn == last_start)
+ break;
+ else if (!NONDEBUG_INSN_P (insn))
+ continue;
+ else
+ {
+ rtx body = PATTERN (insn);
+ if (GET_CODE (body) == USE || GET_CODE (body) == CLOBBER)
+ continue;
+ /* Inline asm could occupy zero bytes. */
+ else if (GET_CODE (body) == ASM_INPUT
+ || asm_noperands (body) >= 0)
+ continue;
+#ifdef HAVE_attr_length
+ else if (get_attr_min_length (insn) == 0)
+ continue;
+#endif
+ else
+ {
+ /* Assume insn has non-zero length. */
+ maybe_at_text_label_p = false;
+ break;
+ }
+ }
+ if (maybe_at_text_label_p)
+ {
+ last_start = loc_note;
+ first_loclabel_num_not_at_text_label = loclabel_num;
+ }
+ }
}
if (!var_loc_p)
@@ -20903,6 +20951,59 @@ dwarf2out_begin_function (tree fun)
set_cur_line_info_table (sec);
}
+/* Helper function of dwarf2out_end_function, called only after emitting
+ the very first function into assembly. Check if some .debug_loc range
+ might end with a .LVL* label that could be equal to .Ltext0.
+ In that case we must force using absolute addresses in .debug_loc ranges,
+ because this range could be .LVLN-.Ltext0 .. .LVLM-.Ltext0 for
+ .LVLN == .LVLM == .Ltext0, thus 0 .. 0, which is a .debug_loc
+ list terminator.
+ Set have_multiple_function_sections to true in that case and
+ terminate htab traversal. */
+
+static int
+find_empty_loc_ranges_at_text_label (void **slot, void *)
+{
+ var_loc_list *entry;
+ struct var_loc_node *node;
+
+ entry = (var_loc_list *) *slot;
+ node = entry->first;
+ if (node && node->next && node->next->label)
+ {
+ unsigned int i;
+ const char *label = node->next->label;
+ char loclabel[MAX_ARTIFICIAL_LABEL_BYTES];
+
+ for (i = 0; i < first_loclabel_num_not_at_text_label; i++)
+ {
+ ASM_GENERATE_INTERNAL_LABEL (loclabel, "LVL", i);
+ if (strcmp (label, loclabel) == 0)
+ {
+ have_multiple_function_sections = true;
+ return 0;
+ }
+ }
+ }
+ return 1;
+}
+
+/* Hook called after emitting a function into assembly.
+ This does something only for the very first function emitted. */
+
+static void
+dwarf2out_end_function (unsigned int)
+{
+ if (in_first_function_p
+ && !have_multiple_function_sections
+ && first_loclabel_num_not_at_text_label
+ && decl_loc_table)
+ htab_traverse (decl_loc_table, find_empty_loc_ranges_at_text_label,
+ NULL);
+ in_first_function_p = false;
+ maybe_at_text_label_p = false;
+}
+
/* Add OPCODE+VAL as an entry at the end of the opcode array in TABLE. */
static void
--- gcc/testsuite/gcc.dg/guality/pr56154-1.c.jj 2013-01-30 17:14:20.850820429 +0100
+++ gcc/testsuite/gcc.dg/guality/pr56154-1.c 2013-01-30 17:47:25.242537776 +0100
@@ -0,0 +1,29 @@
+/* PR debug/56154 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+/* { dg-additional-sources "pr56154-aux.c" } */
+
+#include "../nop.h"
+
+union U { int a, b; };
+volatile int z;
+
+__attribute__((noinline, noclone)) int
+foo (int fd, union U x)
+{
+ int result = x.a != 0;
+ if (fd != 0)
+ result = x.a == 0;
+ asm (NOP : : : "memory"); /* { dg-final { gdb-test pr56154-1.c:17 "x.a" "4" } } */
+ z = x.a;
+ x.a = 6;
+ asm (NOP : : : "memory"); /* { dg-final { gdb-test pr56154-1.c:20 "x.a" "6" } } */
+ return result;
+}
+
+void
+test_main (void)
+{
+ union U u = { .a = 4 };
+ foo (0, u);
+}
--- gcc/testsuite/gcc.dg/guality/pr56154-2.c.jj 2013-01-30 17:58:28.229799607 +0100
+++ gcc/testsuite/gcc.dg/guality/pr56154-2.c 2013-01-30 18:06:38.306982101 +0100
@@ -0,0 +1,39 @@
+/* PR debug/56154 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+/* { dg-additional-sources "pr56154-aux.c" } */
+
+#include "../nop.h"
+
+extern void abort (void);
+
+__attribute__((noinline, noclone)) int
+foo (int x)
+{
+ asm ("");
+ x++;
+ asm ("");
+ x++;
+ asm ("");
+ x++;
+ asm ("");
+ x++;
+ asm ("");
+ x++;
+ asm ("");
+ x++;
+ asm ("");
+ x++;
+ asm ("");
+ x++;
+ asm (NOP : : : "memory");
+ asm (NOP : : : "memory"); /* { dg-final { gdb-test pr56154-2.c:30 "x" "28" } } */
+ return x;
+}
+
+void
+test_main (void)
+{
+ if (foo (20) != 28)
+ abort ();
+}
--- gcc/testsuite/gcc.dg/guality/pr56154-3.c.jj 2013-01-30 18:04:47.531604188 +0100
+++ gcc/testsuite/gcc.dg/guality/pr56154-3.c 2013-01-30 18:06:25.031055514 +0100
@@ -0,0 +1,31 @@
+/* PR debug/56154 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+/* { dg-additional-sources "pr56154-aux.c" } */
+
+#include "../nop.h"
+
+extern void abort (void);
+
+__attribute__((noinline, noclone)) int
+foo (int x)
+{
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ asm (NOP : : : "memory");
+ asm (NOP : : : "memory"); /* { dg-final { gdb-test pr56154-3.c:22 "x" "28" } } */
+ return x;
+}
+
+void
+test_main (void)
+{
+ if (foo (20) != 28)
+ abort ();
+}
--- gcc/testsuite/gcc.dg/guality/pr56154-4.c.jj 2013-01-30 18:05:45.959280837 +0100
+++ gcc/testsuite/gcc.dg/guality/pr56154-4.c 2013-01-30 18:07:50.457602221 +0100
@@ -0,0 +1,34 @@
+/* PR debug/56154 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+/* { dg-additional-sources "pr56154-aux.c" } */
+
+#include "../nop.h"
+
+extern void abort (void);
+
+volatile int z;
+
+__attribute__((noinline, noclone)) int
+foo (int x)
+{
+ z = 6;
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ x++;
+ asm (NOP : : : "memory");
+ asm (NOP : : : "memory"); /* { dg-final { gdb-test pr56154-4.c:25 "x" "28" } } */
+ return x;
+}
+
+void
+test_main (void)
+{
+ if (foo (20) != 28)
+ abort ();
+}
--- gcc/testsuite/gcc.dg/guality/pr56154-aux.c.jj 2013-01-30 17:47:08.467632262 +0100
+++ gcc/testsuite/gcc.dg/guality/pr56154-aux.c 2013-01-30 17:14:28.000000000 +0100
@@ -0,0 +1,11 @@
+/* PR debug/56154 */
+/* { dg-do compile } */
+
+extern void test_main (void);
+
+int
+main ()
+{
+ test_main ();
+ return 0;
+}