Patchwork [google/main] Generate line tables at -g1 (aka -gmlt)

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Submitter Cary Coutant
Date Feb. 7, 2013, 6:34 a.m.
Message ID <CAHACq4qLp1cA030_nCLMzrsrbLri15ECbYLQrx2Zu3+KZpg=1A@mail.gmail.com>
Download mbox | patch
Permalink /patch/218825/
State New
Headers show

Comments

Cary Coutant - Feb. 7, 2013, 6:34 a.m.
This patch is the google/main version of this pending patch for trunk:

http://gcc.gnu.org/ml/gcc-patches/2013-02/msg00260.html

I've modified GCC to generate line number tables at -g1, and we
already have the -gmlt option in google/main as a synonym for -g1. The
patch also changes -g so that it has the same behavior as -g2 -- "-g1
-g" is the same as "-g1 -g2".

Tested with crosstool-validate.py.

OK for google/main?

-cary
Diego Novillo - Feb. 7, 2013, 12:43 p.m.
On Thu, Feb 7, 2013 at 1:34 AM, Cary Coutant <ccoutant@google.com> wrote:

> OK for google/main?

OK.


Diego.

Patch

Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi	(revision 195825)
+++ doc/invoke.texi	(working copy)
@@ -5105,8 +5105,8 @@  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: common.opt
===================================================================
--- common.opt	(revision 195825)
+++ common.opt	(working copy)
@@ -2456,6 +2456,10 @@  grecord-gcc-switches
 Common RejectNegative Var(dwarf_record_gcc_switches,1)
 Record gcc command line switches in DWARF DW_AT_producer.
 
+gmlt
+Common RejectNegative
+Generate debug information at level 1 with minimal line table
+
 gno-split-dwarf
 Common Driver RejectNegative Var(dwarf_split_debug_info,0) Init(0)
 Don't generate debug information in separate .dwo files
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  <ccoutant@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;
+}
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  <ccoutant@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: dwarf2out.c
===================================================================
--- dwarf2out.c	(revision 195825)
+++ dwarf2out.c	(working copy)
@@ -8648,9 +8648,11 @@  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.  */
@@ -16225,11 +16227,12 @@  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))
@@ -19611,16 +19614,19 @@  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.  */
@@ -20969,7 +20975,7 @@  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
@@ -23452,7 +23458,7 @@  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);
 
@@ -23500,7 +23506,7 @@  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 195825)
+++ tree-ssa-live.c	(working copy)
@@ -563,11 +563,11 @@  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 195825)
+++ opts.c	(working copy)
@@ -1697,8 +1697,13 @@  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;
 
     case OPT_gcoff:
@@ -1728,6 +1733,12 @@  common_handle_option (struct gcc_options
 		       loc);
       break;
 
+    case OPT_gmlt:
+      /* Synonym for -g1.  */
+      set_debug_level (NO_DEBUG, DEFAULT_GDB_EXTENSIONS, "1", opts, opts_set,
+		       loc);
+      break;
+
     case OPT_gvms:
       set_debug_level (VMS_DEBUG, false, arg, opts, opts_set, loc);
       break;