A long time ago, I proposed a -gmlt option to generate "minimal line
tables" (basically -g1 + line tables):
http://gcc.gnu.org/ml/gcc-patches/2011-04/msg02075.html
The consensus from that thread was that instead of a new option, we
should just modify -g1 to produce line tables (the documented purpose
of -g1 is to enable stack traces, and stack traces are much more
useful with line numbers). I also proposed, and got no objection, that
-g by itself should set the debugging level to 2 (i.e., -g1 -g should
behave the same as -g1 -g2).
Here, finally, is that patch again, reworked to generate line tables
at -g1. I plan to commit this when Stage 1 reopens, but I'd like to
verify that earlier consensus. I also plan to commit this to the
google/main branch, and future merges will go more smoothly if what I
put in google/main matches what eventually goes into trunk.
-cary
2013-02-06 Cary Coutant <ccout...@google.com>
gcc/
* dwarf2out.c (want_pubnames): Don't do pubnames for -g1.
(add_linkage_name): Don't add linkage name for -g1.
(decls_for_scope): Process subblocks for -g1.
(dwarf2out_source_line): Output line tables for -g1.
(dwarf2out_finish): Likewise.
* tree-ssa-live.c (remove_unused_scope_block_p): Don't prune
unused scopes for -g1.
* opts.c (common_handle_option): Handle -g same as -g2.
* doc/invoke.texi: Update description for -g1.
gcc/testsuite/
* gcc.dg/debug/dwarf2/mlt1.c: New test.
* gcc.dg/debug/dwarf2/mlt2.c: New test.
2013-02-06 Cary Coutant <ccout...@google.com>
gcc/
* dwarf2out.c (want_pubnames): Don't do pubnames for -g1.
(add_linkage_name): Don't add linkage name for -g1.
(decls_for_scope): Process subblocks for -g1.
(dwarf2out_source_line): Output line tables for -g1.
(dwarf2out_finish): Likewise.
* tree-ssa-live.c (remove_unused_scope_block_p): Don't prune
unused scopes for -g1.
* opts.c (common_handle_option): Handle -g same as -g2.
* doc/invoke.texi: Update description for -g1.
gcc/testsuite/
* gcc.dg/debug/dwarf2/mlt1.c: New test.
* gcc.dg/debug/dwarf2/mlt2.c: New test.
Index: dwarf2out.c
===================================================================
--- dwarf2out.c (revision 195743)
+++ dwarf2out.c (working copy)
@@ -8650,9 +8650,11 @@ output_comp_unit (dw_die_ref die, int ou
static inline bool
want_pubnames (void)
{
- return (debug_generate_pub_sections != -1
- ? debug_generate_pub_sections
- : targetm.want_debug_pub_sections);
+ if (debug_info_level <= DINFO_LEVEL_TERSE)
+ return false;
+ if (debug_generate_pub_sections != -1)
+ return debug_generate_pub_sections;
+ return targetm.want_debug_pub_sections;
}
/* Add the DW_AT_GNU_pubnames and DW_AT_GNU_pubtypes attributes. */
@@ -16222,11 +16224,12 @@ add_src_coords_attributes (dw_die_ref di
static void
add_linkage_name (dw_die_ref die, tree decl)
{
- if ((TREE_CODE (decl) == FUNCTION_DECL || TREE_CODE (decl) == VAR_DECL)
- && TREE_PUBLIC (decl)
- && !DECL_ABSTRACT (decl)
- && !(TREE_CODE (decl) == VAR_DECL && DECL_REGISTER (decl))
- && die->die_tag != DW_TAG_member)
+ if (debug_info_level > DINFO_LEVEL_TERSE
+ && (TREE_CODE (decl) == FUNCTION_DECL || TREE_CODE (decl) == VAR_DECL)
+ && TREE_PUBLIC (decl)
+ && !DECL_ABSTRACT (decl)
+ && !(TREE_CODE (decl) == VAR_DECL && DECL_REGISTER (decl))
+ && die->die_tag != DW_TAG_member)
{
/* Defer until we have an assembler name set. */
if (!DECL_ASSEMBLER_NAME_SET_P (decl))
@@ -19609,16 +19612,19 @@ decls_for_scope (tree stmt, dw_die_ref c
/* Output the DIEs to represent all of the data objects and typedefs
declared directly within this block but not within any nested
sub-blocks. Also, nested function and tag DIEs have been
- generated with a parent of NULL; fix that up now. */
- for (decl = BLOCK_VARS (stmt); decl != NULL; decl = DECL_CHAIN (decl))
- process_scope_var (stmt, decl, NULL_TREE, context_die);
- for (i = 0; i < BLOCK_NUM_NONLOCALIZED_VARS (stmt); i++)
- process_scope_var (stmt, NULL, BLOCK_NONLOCALIZED_VAR (stmt, i),
- context_die);
+ generated with a parent of NULL; fix that up now. We don't
+ have to do this if we're at -g1. */
+ if (debug_info_level > DINFO_LEVEL_TERSE)
+ {
+ for (decl = BLOCK_VARS (stmt); decl != NULL; decl = DECL_CHAIN (decl))
+ process_scope_var (stmt, decl, NULL_TREE, context_die);
+ for (i = 0; i < BLOCK_NUM_NONLOCALIZED_VARS (stmt); i++)
+ process_scope_var (stmt, NULL, BLOCK_NONLOCALIZED_VAR (stmt, i),
+ context_die);
+ }
- /* If we're at -g1, we're not interested in subblocks. */
- if (debug_info_level <= DINFO_LEVEL_TERSE)
- return;
+ /* Even if we're at -g1, we need to process the subblocks in order to get
+ inlined call information. */
/* Output the DIEs to represent all sub-blocks (and the items declared
therein) of this block. */
@@ -20966,7 +20972,7 @@ dwarf2out_source_line (unsigned int line
unsigned int file_num;
dw_line_info_table *table;
- if (debug_info_level < DINFO_LEVEL_NORMAL || line == 0)
+ if (debug_info_level < DINFO_LEVEL_TERSE || line == 0)
return;
/* The discriminator column was added in dwarf4. Simplify the below
@@ -23460,7 +23466,7 @@ dwarf2out_finish (const char *filename)
}
}
- if (debug_info_level >= DINFO_LEVEL_NORMAL)
+ if (debug_info_level >= DINFO_LEVEL_TERSE)
add_AT_lineptr (main_comp_unit_die, DW_AT_stmt_list,
debug_line_section_label);
@@ -23508,7 +23514,7 @@ dwarf2out_finish (const char *filename)
/* Add a pointer to the line table for the main compilation unit
so that the debugger can make sense of DW_AT_decl_file
attributes. */
- if (debug_info_level >= DINFO_LEVEL_NORMAL)
+ if (debug_info_level >= DINFO_LEVEL_TERSE)
add_AT_lineptr (ctnode->root_die, DW_AT_stmt_list,
(!dwarf_split_debug_info
? debug_line_section_label
Index: tree-ssa-live.c
===================================================================
--- tree-ssa-live.c (revision 195743)
+++ tree-ssa-live.c (working copy)
@@ -564,11 +564,11 @@ remove_unused_scope_block_p (tree scope)
eliminated. */
else if (!nsubblocks)
;
- /* For terse debug info we can eliminate info on unused variables. */
- else if (debug_info_level == DINFO_LEVEL_NONE
- || debug_info_level == DINFO_LEVEL_TERSE)
+ /* When not generating debug info we can eliminate info on unused
+ variables. */
+ else if (debug_info_level == DINFO_LEVEL_NONE)
{
- /* Even for -g0/-g1 don't prune outer scopes from artificial
+ /* Even for -g0 don't prune outer scopes from artificial
functions, otherwise diagnostics using tree_nonartificial_location
will not be emitted properly. */
if (inlined_function_outer_scope_p (scope))
Index: opts.c
===================================================================
--- opts.c (revision 195743)
+++ opts.c (working copy)
@@ -1701,7 +1701,17 @@ common_handle_option (struct gcc_options
break;
case OPT_g:
- set_debug_level (NO_DEBUG, DEFAULT_GDB_EXTENSIONS, arg, opts, opts_set,
- loc);
+ /* -g by itself should force -g2. */
+ if (*arg == '\0')
+ set_debug_level (NO_DEBUG, DEFAULT_GDB_EXTENSIONS, "2", opts, opts_set,
+ loc);
+ else
+ set_debug_level (NO_DEBUG, DEFAULT_GDB_EXTENSIONS, arg, opts, opts_set,
+ loc);
+ break;
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi (revision 195743)
+++ doc/invoke.texi (working copy)
@@ -5098,8 +5098,8 @@ Level 0 produces no debug information at
Level 1 produces minimal information, enough for making backtraces in
parts of the program that you don't plan to debug. This includes
-descriptions of functions and external variables, but no information
-about local variables and no line numbers.
+descriptions of functions and external variables, and line number
+tables, but no information about local variables.
Level 3 includes extra information, such as all the macro definitions
present in the program. Some debuggers support macro expansion when
Index: testsuite/gcc.dg/debug/dwarf2/mlt1.c
===================================================================
--- testsuite/gcc.dg/debug/dwarf2/mlt1.c (revision 0)
+++ testsuite/gcc.dg/debug/dwarf2/mlt1.c (revision 0)
@@ -0,0 +1,32 @@
+/* Test that -g1 includes line tables and inlined subroutine entries,
+ and excludes types and variables. */
+/* Origin: Cary Coutant <ccout...@google.com> */
+/* { dg-do compile } */
+/* { dg-options "-O2 -gdwarf-2 -dA -g1" } */
+/* { dg-final { scan-assembler "DW_AT_stmt_list" } } */
+/* { dg-final { scan-assembler "DW_TAG_subprogram" } } */
+/* { dg-final { scan-assembler "DW_TAG_inlined_subroutine" } } */
+/* { dg-final { scan-assembler-not "DW_TAG_variable" } } */
+/* { dg-final { scan-assembler-not "DW_TAG_formal_parameter" } } */
+/* { dg-final { scan-assembler-not "DW_TAG_base_type" } } */
+
+static inline __attribute__((always_inline)) int
+a(int i, int j)
+{
+ return (i << 5) + j;
+}
+
+int
+b(int i, int j)
+{
+ return (i >> 5) + (j << 27);
+}
+
+int
+c(int i, int j)
+{
+ int r = a(i, j);
+ r = b(r, i);
+ r = b(r, j);
+ return r;
+}
Index: testsuite/gcc.dg/debug/dwarf2/mlt2.c
===================================================================
--- testsuite/gcc.dg/debug/dwarf2/mlt2.c (revision 0)
+++ testsuite/gcc.dg/debug/dwarf2/mlt2.c (revision 0)
@@ -0,0 +1,31 @@
+/* Test that -g overrides -g1. */
+/* Origin: Cary Coutant <ccout...@google.com> */
+/* { dg-do compile } */
+/* { dg-options "-O2 -gdwarf-2 -dA -g1 -g" } */
+/* { dg-final { scan-assembler "DW_AT_stmt_list" } } */
+/* { dg-final { scan-assembler "DW_TAG_subprogram" } } */
+/* { dg-final { scan-assembler "DW_TAG_inlined_subroutine" } } */
+/* { dg-final { scan-assembler "DW_TAG_variable" } } */
+/* { dg-final { scan-assembler "DW_TAG_formal_parameter" } } */
+/* { dg-final { scan-assembler "DW_TAG_base_type" } } */
+
+static inline __attribute__((always_inline)) int
+a(int i, int j)
+{
+ return (i << 5) + j;
+}
+
+int
+b(int i, int j)
+{
+ return (i >> 5) + (j << 27);
+}
+
+int
+c(int i, int j)
+{
+ int r = a(i, j);
+ r = b(r, i);
+ r = b(r, j);
+ return r;
+}
