[PATCH 1/5] Remove obsolete debugging formats from names list

[PATCH 1/5] Remove obsolete debugging formats from names list

[Mark Harmstone]

STABS and xcoff have been removed, but are still in debug_type_names,
which ought to match debug_type_masks. This results in the following
minor bug with GCC 13:

$ x86_64-pc-linux-gnu-gcc -gvms -c tmp.c
cc1: error: target system does not support the ‘dwarf-2’ debug format
---
 gcc/opts.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/opts.cc b/gcc/opts.cc
index 573dcf8e497..8015cb7556a 100644
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -50,7 +50,7 @@ static void set_Wstrict_aliasing (struct gcc_options *opts, int onoff);
 
 const char *const debug_type_names[] =
 {
-  "none", "stabs", "dwarf-2", "xcoff", "vms", "ctf", "btf"
+  "none", "dwarf-2", "vms", "ctf", "btf"
 };
 
 /* Bitmasks of fundamental debug info formats indexed by enum
@@ -65,7 +65,7 @@ static uint32_t debug_type_masks[] =
 /* Names of the set of debug formats requested by user.  Updated and accessed
    via debug_set_names.  */
 
-static char df_set_names[sizeof "none stabs dwarf-2 xcoff vms ctf btf"];
+static char df_set_names[sizeof "none dwarf-2 vms ctf btf"];
 
 /* Get enum debug_info_type of the specified debug format, for error messages.
    Can be used only for individual debug format types.  */
-- 
2.41.0

[PATCH 2/5] Support for CodeView debugging format

[Mark Harmstone]

This patch and the following add initial support for Microsoft's
CodeView debugging format, as used by MSVC, to mingw targets.

Note that you will need a recent version of binutils for this to be
useful. The best way to view the output is to run Microsoft's
cvdump.exe, found in their microsoft-pdb repo on GitHub, against the
object files.
---
 gcc/Makefile.in                               |  2 +
 gcc/config/i386/cygming.h                     |  2 +
 gcc/dwarf2codeview.cc                         | 50 +++++++++++++++++++
 gcc/dwarf2codeview.h                          | 30 +++++++++++
 gcc/dwarf2out.cc                              |  4 ++
 gcc/flag-types.h                              |  3 ++
 gcc/flags.h                                   |  4 ++
 gcc/opts.cc                                   | 23 +++++++--
 .../gcc.dg/debug/codeview/codeview-1.c        |  6 +++
 .../gcc.dg/debug/codeview/codeview.exp        | 48 ++++++++++++++++++
 gcc/toplev.cc                                 |  4 ++
 11 files changed, 171 insertions(+), 5 deletions(-)
 create mode 100644 gcc/dwarf2codeview.cc
 create mode 100644 gcc/dwarf2codeview.h
 create mode 100644 gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c
 create mode 100644 gcc/testsuite/gcc.dg/debug/codeview/codeview.exp

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index a25a1e32fbc..d011946379d 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1428,6 +1428,7 @@ OBJS = \
 	dumpfile.o \
 	dwarf2asm.o \
 	dwarf2cfi.o \
+	dwarf2codeview.o \
 	dwarf2ctf.o \
 	dwarf2out.o \
 	early-remat.o \
@@ -2794,6 +2795,7 @@ GTFILES = $(CPPLIB_H) $(srcdir)/input.h $(srcdir)/coretypes.h \
   $(srcdir)/dwarf2out.h \
   $(srcdir)/dwarf2asm.cc \
   $(srcdir)/dwarf2cfi.cc \
+  $(srcdir)/dwarf2codeview.cc \
   $(srcdir)/dwarf2ctf.cc \
   $(srcdir)/dwarf2out.cc \
   $(srcdir)/ctfc.h \
diff --git a/gcc/config/i386/cygming.h b/gcc/config/i386/cygming.h
index d539f8d0699..a141462133b 100644
--- a/gcc/config/i386/cygming.h
+++ b/gcc/config/i386/cygming.h
@@ -20,6 +20,8 @@ along with GCC; see the file COPYING3.  If not see
 
 #define DWARF2_DEBUGGING_INFO 1
 
+#define CODEVIEW_DEBUGGING_INFO 1
+
 #undef PREFERRED_DEBUGGING_TYPE
 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
 
diff --git a/gcc/dwarf2codeview.cc b/gcc/dwarf2codeview.cc
new file mode 100644
index 00000000000..e2bfdf8efeb
--- /dev/null
+++ b/gcc/dwarf2codeview.cc
@@ -0,0 +1,50 @@
+/* Generate CodeView debugging info from the GCC DWARF.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+/* See gas/codeview.h in binutils for more about the constants and structs
+   listed below.  References to Microsoft files refer to Microsoft's PDB
+   repository: https://github.com/microsoft/microsoft-pdb.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "target.h"
+#include "output.h"
+#include "errors.h"
+#include "md5.h"
+#include "function.h"
+#include "version.h"
+#include "tree.h"
+#include "langhooks.h"
+#include "dwarf2out.h"
+#include "dwarf2codeview.h"
+
+#define CV_SIGNATURE_C13	4
+
+/* Finish CodeView debug info emission.  */
+
+void
+codeview_debug_finish (void)
+{
+  targetm.asm_out.named_section (".debug$S", SECTION_DEBUG, NULL);
+
+  fputs (integer_asm_op (4, false), asm_out_file);
+  fprint_whex (asm_out_file, CV_SIGNATURE_C13);
+  putc ('\n', asm_out_file);
+}
diff --git a/gcc/dwarf2codeview.h b/gcc/dwarf2codeview.h
new file mode 100644
index 00000000000..efda148eb49
--- /dev/null
+++ b/gcc/dwarf2codeview.h
@@ -0,0 +1,30 @@
+/* dwarf2codeview.h - DWARF interface for CodeView generation.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_DWARF2CODEVIEW_H
+#define GCC_DWARF2CODEVIEW_H 1
+
+#include "dwarf2out.h"
+#include "flags.h"
+
+/* Debug Format Interface.  Used in dwarf2out.cc.  */
+
+extern void codeview_debug_finish (void);
+
+#endif /* GCC_DWARF2CODEVIEW_H */
diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index 0ea73bf782e..557464c4c24 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -80,6 +80,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "expr.h"
 #include "dwarf2out.h"
 #include "dwarf2ctf.h"
+#include "dwarf2codeview.h"
 #include "dwarf2asm.h"
 #include "toplev.h"
 #include "md5.h"
@@ -32207,6 +32208,9 @@ dwarf2out_finish (const char *filename)
        || btf_debuginfo_p ()) && lang_GNU_C ())
     ctf_debug_finish (filename);
 
+  if (codeview_debuginfo_p ())
+    codeview_debug_finish ();
+
   /* Skip emitting DWARF if not required.  */
   if (!dwarf_debuginfo_p ())
     return;
diff --git a/gcc/flag-types.h b/gcc/flag-types.h
index c1852cd810c..dae1d0a8095 100644
--- a/gcc/flag-types.h
+++ b/gcc/flag-types.h
@@ -29,6 +29,7 @@ enum debug_info_type
   DINFO_TYPE_VMS,		  /* VMS debug info.  */
   DINFO_TYPE_CTF,		  /* CTF debug info.  */
   DINFO_TYPE_BTF,		  /* BTF debug info.  */
+  DINFO_TYPE_CODEVIEW,		  /* CodeView debug info.  */
   DINFO_TYPE_BTF_WITH_CORE,	  /* BTF debug info with CO-RE relocations.  */
   DINFO_TYPE_MAX = DINFO_TYPE_BTF_WITH_CORE /* Marker only.  */
 };
@@ -42,6 +43,8 @@ enum debug_info_type
 #define CTF_DEBUG     (1U << DINFO_TYPE_CTF)
 /* Write BTF debug info (using btfout.cc).  */
 #define BTF_DEBUG     (1U << DINFO_TYPE_BTF)
+/* Write CodeView debug info (using dwarf2codeview.cc).  */
+#define CODEVIEW_DEBUG     (1U << DINFO_TYPE_CODEVIEW)
 /* Write BTF debug info for BPF CO-RE usecase (using btfout.cc).  */
 #define BTF_WITH_CORE_DEBUG     (1U << DINFO_TYPE_BTF_WITH_CORE)
 
diff --git a/gcc/flags.h b/gcc/flags.h
index e4bafa310d6..50036459328 100644
--- a/gcc/flags.h
+++ b/gcc/flags.h
@@ -53,6 +53,10 @@ extern bool btf_with_core_debuginfo_p ();
 
 extern bool ctf_debuginfo_p ();
 
+/* Return true iff CodeView debug info is enabled.  */
+
+extern bool codeview_debuginfo_p ();
+
 /* Return true iff DWARF2 debug info is enabled.  */
 
 extern bool dwarf_debuginfo_p (struct gcc_options *opts = &global_options);
diff --git a/gcc/opts.cc b/gcc/opts.cc
index 8015cb7556a..f02101ceea3 100644
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -50,7 +50,7 @@ static void set_Wstrict_aliasing (struct gcc_options *opts, int onoff);
 
 const char *const debug_type_names[] =
 {
-  "none", "dwarf-2", "vms", "ctf", "btf"
+  "none", "dwarf-2", "vms", "ctf", "btf", "codeview"
 };
 
 /* Bitmasks of fundamental debug info formats indexed by enum
@@ -59,13 +59,13 @@ const char *const debug_type_names[] =
 static uint32_t debug_type_masks[] =
 {
   NO_DEBUG, DWARF2_DEBUG, VMS_DEBUG,
-  CTF_DEBUG, BTF_DEBUG
+  CTF_DEBUG, BTF_DEBUG, CODEVIEW_DEBUG
 };
 
 /* Names of the set of debug formats requested by user.  Updated and accessed
    via debug_set_names.  */
 
-static char df_set_names[sizeof "none dwarf-2 vms ctf btf"];
+static char df_set_names[sizeof "none dwarf-2 vms ctf btf codeview"];
 
 /* Get enum debug_info_type of the specified debug format, for error messages.
    Can be used only for individual debug format types.  */
@@ -159,6 +159,14 @@ ctf_debuginfo_p ()
   return (write_symbols & CTF_DEBUG);
 }
 
+/* Return TRUE iff CodeView debug info is enabled.  */
+
+bool
+codeview_debuginfo_p ()
+{
+  return (write_symbols & CODEVIEW_DEBUG);
+}
+
 /* Return TRUE iff dwarf2 debug info is enabled.  */
 
 bool
@@ -173,7 +181,8 @@ dwarf_debuginfo_p (struct gcc_options *opts)
 bool dwarf_based_debuginfo_p ()
 {
   return ((write_symbols & CTF_DEBUG)
-	  || (write_symbols & BTF_DEBUG));
+	  || (write_symbols & BTF_DEBUG)
+	  || (write_symbols & CODEVIEW_DEBUG));
 }
 
 /* All flag uses below need to explicitely reference the option sets
@@ -3145,6 +3154,9 @@ common_handle_option (struct gcc_options *opts,
       break;
 
     case OPT_gcodeview:
+      set_debug_level (CODEVIEW_DEBUG, false, arg, opts, opts_set, loc);
+      if (opts->x_debug_info_level < DINFO_LEVEL_NORMAL)
+	opts->x_debug_info_level = DINFO_LEVEL_NORMAL;
       break;
 
     case OPT_gbtf:
@@ -3419,7 +3431,8 @@ set_debug_level (uint32_t dinfo, int extended, const char *arg,
 	    warning_at (loc, 0, "target system does not support debug output");
 	}
       else if ((opts->x_write_symbols & CTF_DEBUG)
-	       || (opts->x_write_symbols & BTF_DEBUG))
+	       || (opts->x_write_symbols & BTF_DEBUG)
+	       || (opts->x_write_symbols & CODEVIEW_DEBUG))
 	{
 	  opts->x_write_symbols |= DWARF2_DEBUG;
 	  opts_set->x_write_symbols |= DWARF2_DEBUG;
diff --git a/gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c b/gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c
new file mode 100644
index 00000000000..eb5f14530dc
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-gcodeview" } */
+
+void func(void)
+{
+}
diff --git a/gcc/testsuite/gcc.dg/debug/codeview/codeview.exp b/gcc/testsuite/gcc.dg/debug/codeview/codeview.exp
new file mode 100644
index 00000000000..ff705a4ae78
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/codeview/codeview.exp
@@ -0,0 +1,48 @@
+#   Copyright (C) 2023 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# GCC testsuite that uses the `dg.exp' driver.
+
+# Load support procs.
+load_lib gcc-dg.exp
+
+if {![istarget i*86-*-mingw*]
+  && ![istarget x86_64-*-mingw*]} {
+    return 0
+}
+
+# If a testcase doesn't have special options, use these.
+global DEFAULT_CFLAGS
+if ![info exists DEFAULT_CFLAGS] then {
+    set DEFAULT_CFLAGS " -ansi -pedantic-errors"
+}
+
+# Initialize `dg'.
+dg-init
+
+# Main loop.
+set comp_output [gcc_target_compile \
+    "$srcdir/$subdir/../trivial.c" "trivial.S" assembly \
+    "additional_flags=-gcodeview"]
+if { ! [string match "*: target system does not support the * debug format*" \
+    $comp_output] } {
+    remove-build-file "trivial.S"
+    dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.\[cS\] ]] \
+	    "" $DEFAULT_CFLAGS
+}
+
+# All done.
+dg-finish
diff --git a/gcc/toplev.cc b/gcc/toplev.cc
index 8af9bf5090e..862583df0f4 100644
--- a/gcc/toplev.cc
+++ b/gcc/toplev.cc
@@ -1431,6 +1431,10 @@ process_options (bool no_backend)
 #ifdef DWARF2_LINENO_DEBUGGING_INFO
   else if (write_symbols == DWARF2_DEBUG)
     debug_hooks = &dwarf2_lineno_debug_hooks;
+#endif
+#ifdef CODEVIEW_DEBUGGING_INFO
+  else if (codeview_debuginfo_p ())
+    debug_hooks = &dwarf2_debug_hooks;
 #endif
   else
     {
-- 
2.41.0

[PATCH 3/5] Output file checksums in CodeView section

[Mark Harmstone]

Outputs the file name and MD5 hash of the main source file into the
CodeView .debug$S section, along with that of any #include'd files.
---
 gcc/dwarf2codeview.cc | 254 ++++++++++++++++++++++++++++++++++++++++++
 gcc/dwarf2codeview.h  |   1 +
 gcc/dwarf2out.cc      |   3 +
 3 files changed, 258 insertions(+)

diff --git a/gcc/dwarf2codeview.cc b/gcc/dwarf2codeview.cc
index e2bfdf8efeb..d93ba1ed668 100644
--- a/gcc/dwarf2codeview.cc
+++ b/gcc/dwarf2codeview.cc
@@ -37,6 +37,257 @@ along with GCC; see the file COPYING3.  If not see
 
 #define CV_SIGNATURE_C13	4
 
+#define DEBUG_S_STRINGTABLE     0xf3
+#define DEBUG_S_FILECHKSMS      0xf4
+
+#define CHKSUM_TYPE_MD5		1
+
+#define HASH_SIZE 16
+
+struct codeview_string
+{
+  codeview_string *next;
+  uint32_t offset;
+  char *string;
+};
+
+struct string_hasher : free_ptr_hash <struct codeview_string>
+{
+  typedef const char *compare_type;
+
+  static hashval_t hash (const codeview_string *x)
+  {
+    return htab_hash_string (x->string);
+  }
+
+  static bool equal (const codeview_string *x, const char *y)
+  {
+    return !strcmp (x->string, y);
+  }
+
+  static void mark_empty (codeview_string *x)
+  {
+    if (x->string)
+      {
+	free (x->string);
+	x->string = NULL;
+      }
+  }
+
+  static void remove (codeview_string *&x)
+  {
+    free (x->string);
+  }
+};
+
+struct codeview_source_file
+{
+  codeview_source_file *next;
+  unsigned int file_num;
+  uint32_t string_offset;
+  char *filename;
+  uint8_t hash[HASH_SIZE];
+};
+
+static codeview_source_file *files, *last_file;
+static unsigned int num_files;
+static uint32_t string_offset = 1;
+static hash_table<string_hasher> *strings_htab;
+static codeview_string *strings, *last_string;
+
+/* Adds string to the string table, returning its offset.  If already present,
+   this returns the offset of the existing string.  */
+
+static uint32_t
+add_string (const char *string)
+{
+  codeview_string **slot;
+  codeview_string *s;
+  size_t len;
+
+  if (!strings_htab)
+    strings_htab = new hash_table<string_hasher> (10);
+
+  slot = strings_htab->find_slot_with_hash (string, htab_hash_string (string),
+					    INSERT);
+
+  if (*slot)
+    return (*slot)->offset;
+
+  s = (codeview_string *) xmalloc (sizeof (codeview_string));
+  len = strlen (string);
+
+  s->next = NULL;
+
+  s->offset = string_offset;
+  string_offset += len + 1;
+
+  s->string = xstrdup (string);
+
+  if (last_string)
+    last_string->next = s;
+  else
+    strings = s;
+
+  last_string = s;
+
+  *slot = s;
+
+  return s->offset;
+}
+
+/* A new source file has been encountered - record the details and calculate
+   its hash.  */
+
+void
+codeview_start_source_file (const char *filename)
+{
+  codeview_source_file *sf;
+  char *path;
+  uint32_t string_offset;
+  FILE *f;
+
+  path = lrealpath (filename);
+  string_offset = add_string (path);
+  free (path);
+
+  sf = files;
+  while (sf)
+    {
+      if (sf->string_offset == string_offset)
+	return;
+
+      sf = sf->next;
+    }
+
+  sf = (codeview_source_file *) xmalloc (sizeof (codeview_source_file));
+  sf->next = NULL;
+  sf->file_num = num_files;
+  sf->string_offset = string_offset;
+  sf->filename = xstrdup (filename);
+
+  f = fopen (filename, "r");
+  if (!f)
+    internal_error ("could not open %s for reading", filename);
+
+  if (md5_stream (f, sf->hash))
+    {
+      fclose (f);
+      internal_error ("md5_stream failed");
+    }
+
+  fclose (f);
+
+  if (last_file)
+    last_file->next = sf;
+  else
+    files = sf;
+
+  last_file = sf;
+  num_files++;
+}
+
+/* Write out the strings table into the .debug$S section.  The linker will
+   parse this, and handle the deduplication and hashing for all the object
+   files.  */
+
+static void
+write_strings_table (void)
+{
+  codeview_string *string;
+
+  fputs (integer_asm_op (4, false), asm_out_file);
+  fprint_whex (asm_out_file, DEBUG_S_STRINGTABLE);
+  putc ('\n', asm_out_file);
+
+  fputs (integer_asm_op (4, false), asm_out_file);
+  asm_fprintf (asm_out_file, "%LLcv_strings_end - %LLcv_strings_start\n");
+
+  asm_fprintf (asm_out_file, "%LLcv_strings_start:\n");
+
+  /* The first entry is always an empty string.  */
+  fputs (integer_asm_op (1, false), asm_out_file);
+  fprint_whex (asm_out_file, 0);
+  putc ('\n', asm_out_file);
+
+  string = strings;
+  while (string)
+    {
+      ASM_OUTPUT_ASCII (asm_out_file, string->string,
+			strlen (string->string) + 1);
+
+      string = string->next;
+    }
+
+  delete strings_htab;
+
+  asm_fprintf (asm_out_file, "%LLcv_strings_end:\n");
+
+  ASM_OUTPUT_ALIGN (asm_out_file, 2);
+}
+
+/* Write out the file checksums data into the .debug$S section.  */
+
+static void
+write_source_files (void)
+{
+  fputs (integer_asm_op (4, false), asm_out_file);
+  fprint_whex (asm_out_file, DEBUG_S_FILECHKSMS);
+  putc ('\n', asm_out_file);
+
+  fputs (integer_asm_op (4, false), asm_out_file);
+  asm_fprintf (asm_out_file,
+	       "%LLcv_filechksms_end - %LLcv_filechksms_start\n");
+
+  asm_fprintf (asm_out_file, "%LLcv_filechksms_start:\n");
+
+  while (files)
+    {
+      codeview_source_file *next = files->next;
+
+      /* This is struct file_checksum in binutils, or filedata in Microsoft's
+	 dumpsym7.cpp:
+
+	struct file_checksum
+	{
+	  uint32_t file_id;
+	  uint8_t checksum_length;
+	  uint8_t checksum_type;
+	} ATTRIBUTE_PACKED;
+
+	followed then by the bytes of the hash, padded to the next 4 bytes.
+	file_id here is actually the offset in the strings table.  */
+
+      fputs (integer_asm_op (4, false), asm_out_file);
+      fprint_whex (asm_out_file, files->string_offset);
+      putc ('\n', asm_out_file);
+
+      fputs (integer_asm_op (1, false), asm_out_file);
+      fprint_whex (asm_out_file, HASH_SIZE);
+      putc ('\n', asm_out_file);
+
+      fputs (integer_asm_op (1, false), asm_out_file);
+      fprint_whex (asm_out_file, CHKSUM_TYPE_MD5);
+      putc ('\n', asm_out_file);
+
+      for (unsigned int i = 0; i < HASH_SIZE; i++)
+	{
+	  fputs (integer_asm_op (1, false), asm_out_file);
+	  fprint_whex (asm_out_file, files->hash[i]);
+	  putc ('\n', asm_out_file);
+	}
+
+      ASM_OUTPUT_ALIGN (asm_out_file, 2);
+
+      free (files->filename);
+      free (files);
+
+      files = next;
+    }
+
+  asm_fprintf (asm_out_file, "%LLcv_filechksms_end:\n");
+}
+
 /* Finish CodeView debug info emission.  */
 
 void
@@ -47,4 +298,7 @@ codeview_debug_finish (void)
   fputs (integer_asm_op (4, false), asm_out_file);
   fprint_whex (asm_out_file, CV_SIGNATURE_C13);
   putc ('\n', asm_out_file);
+
+  write_strings_table ();
+  write_source_files ();
 }
diff --git a/gcc/dwarf2codeview.h b/gcc/dwarf2codeview.h
index efda148eb49..e2d732bb9b6 100644
--- a/gcc/dwarf2codeview.h
+++ b/gcc/dwarf2codeview.h
@@ -26,5 +26,6 @@ along with GCC; see the file COPYING3.  If not see
 /* Debug Format Interface.  Used in dwarf2out.cc.  */
 
 extern void codeview_debug_finish (void);
+extern void codeview_start_source_file (const char *);
 
 #endif /* GCC_DWARF2CODEVIEW_H */
diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index 557464c4c24..945176a91bc 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -28823,6 +28823,9 @@ dwarf2out_set_ignored_loc (unsigned int line, unsigned int column,
 static void
 dwarf2out_start_source_file (unsigned int lineno, const char *filename)
 {
+  if (codeview_debuginfo_p ())
+    codeview_start_source_file (filename);
+
   if (debug_info_level >= DINFO_LEVEL_VERBOSE)
     {
       macinfo_entry e;
-- 
2.41.0

[PATCH 4/5] Output line numbers in CodeView section

[Mark Harmstone]

Outputs the DEBUG_S_LINES block in the CodeView .debug$S section, which
maps between line numbers and addresses.

You'll need a fairly recent version of GAS for the .secidx directive to
be recognized.
---
 gcc/dwarf2codeview.cc | 303 ++++++++++++++++++++++++++++++++++++++++++
 gcc/dwarf2codeview.h  |   3 +
 gcc/dwarf2out.cc      |   9 ++
 gcc/opts.cc           |   2 +-
 4 files changed, 316 insertions(+), 1 deletion(-)

diff --git a/gcc/dwarf2codeview.cc b/gcc/dwarf2codeview.cc
index d93ba1ed668..4dfc0300177 100644
--- a/gcc/dwarf2codeview.cc
+++ b/gcc/dwarf2codeview.cc
@@ -37,11 +37,15 @@ along with GCC; see the file COPYING3.  If not see
 
 #define CV_SIGNATURE_C13	4
 
+#define DEBUG_S_LINES		0xf2
 #define DEBUG_S_STRINGTABLE     0xf3
 #define DEBUG_S_FILECHKSMS      0xf4
 
 #define CHKSUM_TYPE_MD5		1
 
+#define LINE_LABEL	"Lcvline"
+#define END_FUNC_LABEL	"Lcvendfunc"
+
 #define HASH_SIZE 16
 
 struct codeview_string
@@ -89,11 +93,128 @@ struct codeview_source_file
   uint8_t hash[HASH_SIZE];
 };
 
+struct codeview_line
+{
+  codeview_line *next;
+  unsigned int line_no;
+  unsigned int label_num;
+};
+
+struct codeview_line_block
+{
+  codeview_line_block *next;
+  uint32_t file_id;
+  unsigned int num_lines;
+  codeview_line *lines, *last_line;
+};
+
+struct codeview_function
+{
+  codeview_function *next;
+  function *func;
+  unsigned int end_label;
+  codeview_line_block *blocks, *last_block;
+};
+
+static unsigned int line_label_num;
+static unsigned int func_label_num;
 static codeview_source_file *files, *last_file;
 static unsigned int num_files;
 static uint32_t string_offset = 1;
 static hash_table<string_hasher> *strings_htab;
 static codeview_string *strings, *last_string;
+static codeview_function *funcs, *last_func;
+static const char* last_filename;
+static uint32_t last_file_id;
+
+/* Record new line number against the current function.  */
+
+void
+codeview_source_line (unsigned int line_no, const char *filename)
+{
+  codeview_line *l;
+  uint32_t file_id = last_file_id;
+  unsigned int label_num = ++line_label_num;
+
+  targetm.asm_out.internal_label (asm_out_file, LINE_LABEL, label_num);
+
+  if (!last_func || last_func->func != cfun)
+    {
+      codeview_function *f = (codeview_function *)
+				xmalloc (sizeof (codeview_function));
+
+      f->next = NULL;
+      f->func = cfun;
+      f->end_label = 0;
+      f->blocks = f->last_block = NULL;
+
+      if (!funcs)
+	funcs = f;
+      else
+	last_func->next = f;
+
+      last_func = f;
+    }
+
+  if (filename != last_filename)
+    {
+      codeview_source_file *sf = files;
+
+      while (sf)
+	{
+	  if (!strcmp (sf->filename, filename))
+	    {
+	      /* 0x18 is the size of the checksum entry for each file.
+		 0x6 bytes for the header, plus 0x10 bytes for the hash,
+		 then padded to a multiple of 4.  */
+
+	      file_id = sf->file_num * 0x18;
+	      last_filename = filename;
+	      last_file_id = file_id;
+	      break;
+	    }
+
+	  sf = sf->next;
+	}
+    }
+
+  if (!last_func->last_block || last_func->last_block->file_id != file_id)
+    {
+      codeview_line_block *b;
+
+      b = (codeview_line_block *) xmalloc (sizeof (codeview_line_block));
+
+      b->next = NULL;
+      b->file_id = file_id;
+      b->num_lines = 0;
+      b->lines = b->last_line = NULL;
+
+      if (!last_func->blocks)
+	last_func->blocks = b;
+      else
+	last_func->last_block->next = b;
+
+      last_func->last_block = b;
+    }
+
+  if (last_func->last_block->last_line
+    && last_func->last_block->last_line->line_no == line_no)
+    return;
+
+  l = (codeview_line *) xmalloc (sizeof (codeview_line));
+
+  l->next = NULL;
+  l->line_no = line_no;
+  l->label_num = label_num;
+
+  if (!last_func->last_block->lines)
+    last_func->last_block->lines = l;
+  else
+    last_func->last_block->last_line->next = l;
+
+  last_func->last_block->last_line = l;
+  last_func->last_block->num_lines++;
+}
 
 /* Adds string to the string table, returning its offset.  If already present,
    this returns the offset of the existing string.  */
@@ -288,6 +409,187 @@ write_source_files (void)
   asm_fprintf (asm_out_file, "%LLcv_filechksms_end:\n");
 }
 
+/* Write out the line number information for each function into the
+   .debug$S section.  */
+
+static void
+write_line_numbers (void)
+{
+  unsigned int func_num = 0;
+
+  while (funcs)
+    {
+      codeview_function *next = funcs->next;
+      unsigned int first_label_num;
+
+      fputs (integer_asm_op (4, false), asm_out_file);
+      fprint_whex (asm_out_file, DEBUG_S_LINES);
+      putc ('\n', asm_out_file);
+
+      fputs (integer_asm_op (4, false), asm_out_file);
+      asm_fprintf (asm_out_file, "%LLcv_lines%u_end - %LLcv_lines%u_start\n",
+		   func_num, func_num);
+
+      asm_fprintf (asm_out_file, "%LLcv_lines%u_start:\n", func_num);
+
+      /* Output the header (struct cv_lines_header in binutils or
+	 CV_DebugSLinesHeader_t in Microsoft's cvinfo.h):
+
+	struct cv_lines_header
+	{
+	  uint32_t offset;
+	  uint16_t section;
+	  uint16_t flags;
+	  uint32_t length;
+	};
+      */
+
+      asm_fprintf (asm_out_file, "\t.secrel32\t%L" LINE_LABEL "%u\n",
+		   funcs->blocks->lines->label_num);
+      asm_fprintf (asm_out_file, "\t.secidx\t%L" LINE_LABEL "%u\n",
+		   funcs->blocks->lines->label_num);
+
+      /* flags */
+      fputs (integer_asm_op (2, false), asm_out_file);
+      fprint_whex (asm_out_file, 0);
+      putc ('\n', asm_out_file);
+
+      first_label_num = funcs->blocks->lines->label_num;
+
+      /* length */
+      fputs (integer_asm_op (4, false), asm_out_file);
+      asm_fprintf (asm_out_file,
+		   "%L" END_FUNC_LABEL "%u - %L" LINE_LABEL "%u\n",
+		   funcs->end_label, first_label_num);
+
+      while (funcs->blocks)
+	{
+	  codeview_line_block *next = funcs->blocks->next;
+
+	  /* Next comes the blocks, each block being a part of a function
+	     within the same source file (struct cv_lines_block in binutils or
+	     CV_DebugSLinesFileBlockHeader_t in Microsoft's cvinfo.h):
+
+	    struct cv_lines_block
+	    {
+	      uint32_t file_id;
+	      uint32_t num_lines;
+	      uint32_t length;
+	    };
+	  */
+
+	  /* file ID */
+	  fputs (integer_asm_op (4, false), asm_out_file);
+	  fprint_whex (asm_out_file, funcs->blocks->file_id);
+	  putc ('\n', asm_out_file);
+
+	  /* number of lines */
+	  fputs (integer_asm_op (4, false), asm_out_file);
+	  fprint_whex (asm_out_file, funcs->blocks->num_lines);
+	  putc ('\n', asm_out_file);
+
+	  /* length of code block: (num_lines * sizeof (struct cv_line)) +
+	     sizeof (struct cv_lines_block) */
+	  fputs (integer_asm_op (4, false), asm_out_file);
+	  fprint_whex (asm_out_file, (funcs->blocks->num_lines * 0x8) + 0xc);
+	  putc ('\n', asm_out_file);
+
+	  while (funcs->blocks->lines)
+	    {
+	      codeview_line *next = funcs->blocks->lines->next;
+
+	      /* Finally comes the line number information (struct cv_line in
+		 binutils or CV_Line_t in Microsoft's cvinfo.h):
+
+		struct cv_line
+		{
+		  uint32_t offset;
+		  uint32_t line_no;
+		};
+
+		Strictly speaking line_no is a bitfield: the bottom 24 bits
+		are the line number, and the top bit means "is a statement".
+	      */
+
+	      fputs (integer_asm_op (4, false), asm_out_file);
+	      asm_fprintf (asm_out_file,
+			   "%L" LINE_LABEL "%u - %L" LINE_LABEL "%u\n",
+			   funcs->blocks->lines->label_num, first_label_num);
+
+	      fputs (integer_asm_op (4, false), asm_out_file);
+	      fprint_whex (asm_out_file,
+			   0x80000000
+			   | (funcs->blocks->lines->line_no & 0xffffff));
+	      putc ('\n', asm_out_file);
+
+	      free (funcs->blocks->lines);
+
+	      funcs->blocks->lines = next;
+	    }
+
+	  free (funcs->blocks);
+
+	  funcs->blocks = next;
+	}
+
+      free (funcs);
+
+      asm_fprintf (asm_out_file, "%LLcv_lines%u_end:\n", func_num);
+      func_num++;
+
+      funcs = next;
+    }
+}
+
+/* Treat cold sections as separate functions, for the purposes of line
+   numbers.  */
+
+void
+codeview_switch_text_section (void)
+{
+  codeview_function *f;
+
+  if (last_func && last_func->end_label == 0)
+    {
+      unsigned int label_num = ++func_label_num;
+
+      targetm.asm_out.internal_label (asm_out_file, END_FUNC_LABEL,
+				      label_num);
+
+      last_func->end_label = label_num;
+    }
+
+  f = (codeview_function *) xmalloc (sizeof (codeview_function));
+
+  f->next = NULL;
+  f->func = cfun;
+  f->end_label = 0;
+  f->blocks = f->last_block = NULL;
+
+  if (!funcs)
+    funcs = f;
+  else
+    last_func->next = f;
+
+  last_func = f;
+}
+
+/* Mark the end of the current function.  */
+
+void
+codeview_end_epilogue (void)
+{
+  if (last_func && last_func->end_label == 0)
+    {
+      unsigned int label_num = ++func_label_num;
+
+      targetm.asm_out.internal_label (asm_out_file, END_FUNC_LABEL,
+				      label_num);
+
+      last_func->end_label = label_num;
+    }
+}
+
 /* Finish CodeView debug info emission.  */
 
 void
@@ -301,4 +603,5 @@ codeview_debug_finish (void)
 
   write_strings_table ();
   write_source_files ();
+  write_line_numbers ();
 }
diff --git a/gcc/dwarf2codeview.h b/gcc/dwarf2codeview.h
index e2d732bb9b6..b6421b62d2e 100644
--- a/gcc/dwarf2codeview.h
+++ b/gcc/dwarf2codeview.h
@@ -26,6 +26,9 @@ along with GCC; see the file COPYING3.  If not see
 /* Debug Format Interface.  Used in dwarf2out.cc.  */
 
 extern void codeview_debug_finish (void);
+extern void codeview_source_line (unsigned int, const char *);
 extern void codeview_start_source_file (const char *);
+extern void codeview_switch_text_section ();
+extern void codeview_end_epilogue (void);
 
 #endif /* GCC_DWARF2CODEVIEW_H */
diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index 945176a91bc..c0ee99ffd40 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -1253,6 +1253,9 @@ dwarf2out_end_epilogue (unsigned int line ATTRIBUTE_UNUSED,
   if (dwarf2out_do_cfi_asm ())
     fprintf (asm_out_file, "\t.cfi_endproc\n");
 
+  if (codeview_debuginfo_p ())
+    codeview_end_epilogue ();
+
   /* Output a label to mark the endpoint of the code generated for this
      function.  */
   ASM_GENERATE_INTERNAL_LABEL (label, FUNC_END_LABEL,
@@ -1306,6 +1309,9 @@ dwarf2out_switch_text_section (void)
     }
   have_multiple_function_sections = true;
 
+  if (codeview_debuginfo_p ())
+    codeview_switch_text_section ();
+
   if (dwarf2out_do_cfi_asm ())
     fprintf (asm_out_file, "\t.cfi_endproc\n");
 
@@ -28603,6 +28609,9 @@ dwarf2out_source_line (unsigned int line, unsigned int column,
   dw_line_info_table *table;
   static var_loc_view lvugid;
 
+  if (codeview_debuginfo_p ())
+    codeview_source_line (line, filename);
+
   /* 'line_info_table' information gathering is not needed when the debug
      info level is set to the lowest value.  Also, the current DWARF-based
      debug formats do not use this info.  */
diff --git a/gcc/opts.cc b/gcc/opts.cc
index f02101ceea3..6e91b1e0ff9 100644
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -1364,7 +1364,7 @@ finish_options (struct gcc_options *opts, struct gcc_options *opts_set,
     opts->x_debug_nonbind_markers_p
       = (opts->x_optimize
 	 && opts->x_debug_info_level >= DINFO_LEVEL_NORMAL
-	 && dwarf_debuginfo_p (opts)
+	 && (dwarf_debuginfo_p (opts) || codeview_debuginfo_p ())
 	 && !(opts->x_flag_selective_scheduling
 	      || opts->x_flag_selective_scheduling2));
 
-- 
2.41.0

[PATCH 5/5] Output S_COMPILE3 symbol in CodeView debug section

[Mark Harmstone]

Outputs the S_COMPILE3 symbol in the CodeView .debug$S debug section.
The DEBUG_S_SYMBOLS block added here makes up pretty much everything
that isn't data structures or line numbers; we add the S_COMPILE3 symbol
here to start it off.

This is a descriptive bit, the most interesting part of which is the
version of the compiler used.
---
 gcc/dwarf2codeview.cc | 126 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)

diff --git a/gcc/dwarf2codeview.cc b/gcc/dwarf2codeview.cc
index 4dfc0300177..a33be036951 100644
--- a/gcc/dwarf2codeview.cc
+++ b/gcc/dwarf2codeview.cc
@@ -37,14 +37,25 @@ along with GCC; see the file COPYING3.  If not see
 
 #define CV_SIGNATURE_C13	4
 
+#define DEBUG_S_SYMBOLS		0xf1
 #define DEBUG_S_LINES		0xf2
 #define DEBUG_S_STRINGTABLE     0xf3
 #define DEBUG_S_FILECHKSMS      0xf4
 
 #define CHKSUM_TYPE_MD5		1
 
+#define S_COMPILE3		0x113c
+
+#define CV_CFL_80386		0x03
+#define CV_CFL_X64		0xD0
+
+#define CV_CFL_C		0x00
+#define CV_CFL_CXX		0x01
+
 #define LINE_LABEL	"Lcvline"
 #define END_FUNC_LABEL	"Lcvendfunc"
+#define SYMBOL_START_LABEL	"Lcvsymstart"
+#define SYMBOL_END_LABEL	"Lcvsymend"
 
 #define HASH_SIZE 16
 
@@ -118,6 +129,7 @@ struct codeview_function
 
 static unsigned int line_label_num;
 static unsigned int func_label_num;
+static unsigned int sym_label_num;
 static codeview_source_file *files, *last_file;
 static unsigned int num_files;
 static uint32_t string_offset = 1;
@@ -590,6 +602,119 @@ codeview_end_epilogue (void)
     }
 }
 
+/* Return the CodeView constant for the selected architecture.  */
+
+static uint16_t
+target_processor (void)
+{
+  if (TARGET_64BIT)
+    return CV_CFL_X64;
+  else
+    return CV_CFL_80386;
+}
+
+/* Return the CodeView constant for the language being used.  */
+
+static uint32_t
+language_constant (void)
+{
+  const char *language_string = lang_hooks.name;
+
+  if (startswith (language_string, "GNU C++"))
+    return CV_CFL_CXX;
+  else if (startswith (language_string, "GNU C"))
+    return CV_CFL_C;
+
+  return 0;
+}
+
+/* Write a S_COMPILE3 symbol, which records the details of the compiler
+   being used.  */
+
+static void
+write_compile3_symbol (void)
+{
+  unsigned int label_num = ++sym_label_num;
+
+  static const char compiler_name[] = "GCC ";
+
+  /* This is struct COMPILESYM3 in binutils and Microsoft's cvinfo.h:
+
+     struct COMPILESYM3
+     {
+       uint16_t length;
+       uint16_t type;
+       uint32_t flags;
+       uint16_t machine;
+       uint16_t frontend_major;
+       uint16_t frontend_minor;
+       uint16_t frontend_build;
+       uint16_t frontend_qfe;
+       uint16_t backend_major;
+       uint16_t backend_minor;
+       uint16_t backend_build;
+       uint16_t backend_qfe;
+     } ATTRIBUTE_PACKED;
+  */
+
+  fputs (integer_asm_op (2, false), asm_out_file);
+  asm_fprintf (asm_out_file,
+	       "%L" SYMBOL_END_LABEL "%u - %L" SYMBOL_START_LABEL "%u\n",
+	       label_num, label_num);
+
+  targetm.asm_out.internal_label (asm_out_file, SYMBOL_START_LABEL, label_num);
+
+  fputs (integer_asm_op (2, false), asm_out_file);
+  fprint_whex (asm_out_file, S_COMPILE3);
+  putc ('\n', asm_out_file);
+
+  /* Microsoft has the flags as a bitfield, with the bottom 8 bits being the
+     language constant, and the reset being MSVC-specific stuff.  */
+  fputs (integer_asm_op (4, false), asm_out_file);
+  fprint_whex (asm_out_file, language_constant ());
+  putc ('\n', asm_out_file);
+
+  fputs (integer_asm_op (2, false), asm_out_file);
+  fprint_whex (asm_out_file, target_processor ());
+  putc ('\n', asm_out_file);
+
+  /* Write 8 uint16_ts for the frontend and backend versions.  As with GAS, we
+     zero these, as it's easier to record the version in the compiler
+     string.  */
+  for (unsigned int i = 0; i < 8; i++)
+    {
+      fputs (integer_asm_op (2, false), asm_out_file);
+      fprint_whex (asm_out_file, 0);
+      putc ('\n', asm_out_file);
+    }
+
+  ASM_OUTPUT_ASCII (asm_out_file, compiler_name, sizeof (compiler_name) - 1);
+  ASM_OUTPUT_ASCII (asm_out_file, version_string, strlen (version_string) + 1);
+
+  ASM_OUTPUT_ALIGN (asm_out_file, 2);
+
+  targetm.asm_out.internal_label (asm_out_file, SYMBOL_END_LABEL, label_num);
+}
+
+/* Write the CodeView symbols into the .debug$S section.  */
+
+static void
+write_codeview_symbols (void)
+{
+  fputs (integer_asm_op (4, false), asm_out_file);
+  fprint_whex (asm_out_file, DEBUG_S_SYMBOLS);
+  putc ('\n', asm_out_file);
+
+  fputs (integer_asm_op (4, false), asm_out_file);
+  asm_fprintf (asm_out_file, "%LLcv_syms_end - %LLcv_syms_start\n");
+
+  asm_fprintf (asm_out_file, "%LLcv_syms_start:\n");
+
+  write_compile3_symbol ();
+
+  asm_fprintf (asm_out_file, "%LLcv_syms_end:\n");
+}
+
 /* Finish CodeView debug info emission.  */
 
 void
@@ -604,4 +729,5 @@ codeview_debug_finish (void)
   write_strings_table ();
   write_source_files ();
   write_line_numbers ();
+  write_codeview_symbols ();
 }
-- 
2.41.0

Re: [PATCH 1/5] Remove obsolete debugging formats from names list

[Richard Biener]

On Mon, Oct 23, 2023 at 2:56 AM Mark Harmstone <mark@harmstone.com> wrote:
>
> STABS and xcoff have been removed, but are still in debug_type_names,
> which ought to match debug_type_masks. This results in the following
> minor bug with GCC 13:
>
> $ x86_64-pc-linux-gnu-gcc -gvms -c tmp.c
> cc1: error: target system does not support the ‘dwarf-2’ debug format

OK for trunk and branch.

Richard.

> ---
>  gcc/opts.cc | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/opts.cc b/gcc/opts.cc
> index 573dcf8e497..8015cb7556a 100644
> --- a/gcc/opts.cc
> +++ b/gcc/opts.cc
> @@ -50,7 +50,7 @@ static void set_Wstrict_aliasing (struct gcc_options *opts, int onoff);
>
>  const char *const debug_type_names[] =
>  {
> -  "none", "stabs", "dwarf-2", "xcoff", "vms", "ctf", "btf"
> +  "none", "dwarf-2", "vms", "ctf", "btf"
>  };
>
>  /* Bitmasks of fundamental debug info formats indexed by enum
> @@ -65,7 +65,7 @@ static uint32_t debug_type_masks[] =
>  /* Names of the set of debug formats requested by user.  Updated and accessed
>     via debug_set_names.  */
>
> -static char df_set_names[sizeof "none stabs dwarf-2 xcoff vms ctf btf"];
> +static char df_set_names[sizeof "none dwarf-2 vms ctf btf"];
>
>  /* Get enum debug_info_type of the specified debug format, for error messages.
>     Can be used only for individual debug format types.  */
> --
> 2.41.0
>

Re: [PATCH 2/5] Support for CodeView debugging format

[Richard Biener]

On Mon, Oct 23, 2023 at 2:57 AM Mark Harmstone <mark@harmstone.com> wrote:
>
> This patch and the following add initial support for Microsoft's
> CodeView debugging format, as used by MSVC, to mingw targets.

A high-level question - it seems there's almost no information in the
codeview sections,
so is that debug format even inferior to STABS?  Is it even used with
contemporary
toolchains or is DWARF a thing with MSVC?

If CodeView is as full-featured as DWARF you are going to run into issues with
how we handle LTO given at dwarf2out_finish time all the DWARF for types and
declarations is "gone" (to disk).  For that post-processing the binary would be
much easier.

Richard.

> Note that you will need a recent version of binutils for this to be
> useful. The best way to view the output is to run Microsoft's
> cvdump.exe, found in their microsoft-pdb repo on GitHub, against the
> object files.
> ---
>  gcc/Makefile.in                               |  2 +
>  gcc/config/i386/cygming.h                     |  2 +
>  gcc/dwarf2codeview.cc                         | 50 +++++++++++++++++++
>  gcc/dwarf2codeview.h                          | 30 +++++++++++
>  gcc/dwarf2out.cc                              |  4 ++
>  gcc/flag-types.h                              |  3 ++
>  gcc/flags.h                                   |  4 ++
>  gcc/opts.cc                                   | 23 +++++++--
>  .../gcc.dg/debug/codeview/codeview-1.c        |  6 +++
>  .../gcc.dg/debug/codeview/codeview.exp        | 48 ++++++++++++++++++
>  gcc/toplev.cc                                 |  4 ++
>  11 files changed, 171 insertions(+), 5 deletions(-)
>  create mode 100644 gcc/dwarf2codeview.cc
>  create mode 100644 gcc/dwarf2codeview.h
>  create mode 100644 gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c
>  create mode 100644 gcc/testsuite/gcc.dg/debug/codeview/codeview.exp
>
> diff --git a/gcc/Makefile.in b/gcc/Makefile.in
> index a25a1e32fbc..d011946379d 100644
> --- a/gcc/Makefile.in
> +++ b/gcc/Makefile.in
> @@ -1428,6 +1428,7 @@ OBJS = \
>         dumpfile.o \
>         dwarf2asm.o \
>         dwarf2cfi.o \
> +       dwarf2codeview.o \
>         dwarf2ctf.o \
>         dwarf2out.o \
>         early-remat.o \
> @@ -2794,6 +2795,7 @@ GTFILES = $(CPPLIB_H) $(srcdir)/input.h $(srcdir)/coretypes.h \
>    $(srcdir)/dwarf2out.h \
>    $(srcdir)/dwarf2asm.cc \
>    $(srcdir)/dwarf2cfi.cc \
> +  $(srcdir)/dwarf2codeview.cc \
>    $(srcdir)/dwarf2ctf.cc \
>    $(srcdir)/dwarf2out.cc \
>    $(srcdir)/ctfc.h \
> diff --git a/gcc/config/i386/cygming.h b/gcc/config/i386/cygming.h
> index d539f8d0699..a141462133b 100644
> --- a/gcc/config/i386/cygming.h
> +++ b/gcc/config/i386/cygming.h
> @@ -20,6 +20,8 @@ along with GCC; see the file COPYING3.  If not see
>
>  #define DWARF2_DEBUGGING_INFO 1
>
> +#define CODEVIEW_DEBUGGING_INFO 1
> +
>  #undef PREFERRED_DEBUGGING_TYPE
>  #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
>
> diff --git a/gcc/dwarf2codeview.cc b/gcc/dwarf2codeview.cc
> new file mode 100644
> index 00000000000..e2bfdf8efeb
> --- /dev/null
> +++ b/gcc/dwarf2codeview.cc
> @@ -0,0 +1,50 @@
> +/* Generate CodeView debugging info from the GCC DWARF.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify it under
> +the terms of the GNU General Public License as published by the Free
> +Software Foundation; either version 3, or (at your option) any later
> +version.
> +
> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
> +FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
> +for more details.
> +
> +You should have received a copy of the GNU General Public License
> +along with GCC; see the file COPYING3.  If not see
> +<http://www.gnu.org/licenses/>.  */
> +
> +/* See gas/codeview.h in binutils for more about the constants and structs
> +   listed below.  References to Microsoft files refer to Microsoft's PDB
> +   repository: https://github.com/microsoft/microsoft-pdb.  */
> +
> +#include "config.h"
> +#include "system.h"
> +#include "coretypes.h"
> +#include "target.h"
> +#include "output.h"
> +#include "errors.h"
> +#include "md5.h"
> +#include "function.h"
> +#include "version.h"
> +#include "tree.h"
> +#include "langhooks.h"
> +#include "dwarf2out.h"
> +#include "dwarf2codeview.h"
> +
> +#define CV_SIGNATURE_C13       4
> +
> +/* Finish CodeView debug info emission.  */
> +
> +void
> +codeview_debug_finish (void)
> +{
> +  targetm.asm_out.named_section (".debug$S", SECTION_DEBUG, NULL);
> +
> +  fputs (integer_asm_op (4, false), asm_out_file);
> +  fprint_whex (asm_out_file, CV_SIGNATURE_C13);
> +  putc ('\n', asm_out_file);
> +}
> diff --git a/gcc/dwarf2codeview.h b/gcc/dwarf2codeview.h
> new file mode 100644
> index 00000000000..efda148eb49
> --- /dev/null
> +++ b/gcc/dwarf2codeview.h
> @@ -0,0 +1,30 @@
> +/* dwarf2codeview.h - DWARF interface for CodeView generation.
> +   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify it under
> +the terms of the GNU General Public License as published by the Free
> +Software Foundation; either version 3, or (at your option) any later
> +version.
> +
> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
> +FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
> +for more details.
> +
> +You should have received a copy of the GNU General Public License
> +along with GCC; see the file COPYING3.  If not see
> +<http://www.gnu.org/licenses/>.  */
> +
> +#ifndef GCC_DWARF2CODEVIEW_H
> +#define GCC_DWARF2CODEVIEW_H 1
> +
> +#include "dwarf2out.h"
> +#include "flags.h"
> +
> +/* Debug Format Interface.  Used in dwarf2out.cc.  */
> +
> +extern void codeview_debug_finish (void);
> +
> +#endif /* GCC_DWARF2CODEVIEW_H */
> diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
> index 0ea73bf782e..557464c4c24 100644
> --- a/gcc/dwarf2out.cc
> +++ b/gcc/dwarf2out.cc
> @@ -80,6 +80,7 @@ along with GCC; see the file COPYING3.  If not see
>  #include "expr.h"
>  #include "dwarf2out.h"
>  #include "dwarf2ctf.h"
> +#include "dwarf2codeview.h"
>  #include "dwarf2asm.h"
>  #include "toplev.h"
>  #include "md5.h"
> @@ -32207,6 +32208,9 @@ dwarf2out_finish (const char *filename)
>         || btf_debuginfo_p ()) && lang_GNU_C ())
>      ctf_debug_finish (filename);
>
> +  if (codeview_debuginfo_p ())
> +    codeview_debug_finish ();
> +
>    /* Skip emitting DWARF if not required.  */
>    if (!dwarf_debuginfo_p ())
>      return;
> diff --git a/gcc/flag-types.h b/gcc/flag-types.h
> index c1852cd810c..dae1d0a8095 100644
> --- a/gcc/flag-types.h
> +++ b/gcc/flag-types.h
> @@ -29,6 +29,7 @@ enum debug_info_type
>    DINFO_TYPE_VMS,                /* VMS debug info.  */
>    DINFO_TYPE_CTF,                /* CTF debug info.  */
>    DINFO_TYPE_BTF,                /* BTF debug info.  */
> +  DINFO_TYPE_CODEVIEW,           /* CodeView debug info.  */
>    DINFO_TYPE_BTF_WITH_CORE,      /* BTF debug info with CO-RE relocations.  */
>    DINFO_TYPE_MAX = DINFO_TYPE_BTF_WITH_CORE /* Marker only.  */
>  };
> @@ -42,6 +43,8 @@ enum debug_info_type
>  #define CTF_DEBUG     (1U << DINFO_TYPE_CTF)
>  /* Write BTF debug info (using btfout.cc).  */
>  #define BTF_DEBUG     (1U << DINFO_TYPE_BTF)
> +/* Write CodeView debug info (using dwarf2codeview.cc).  */
> +#define CODEVIEW_DEBUG     (1U << DINFO_TYPE_CODEVIEW)
>  /* Write BTF debug info for BPF CO-RE usecase (using btfout.cc).  */
>  #define BTF_WITH_CORE_DEBUG     (1U << DINFO_TYPE_BTF_WITH_CORE)
>
> diff --git a/gcc/flags.h b/gcc/flags.h
> index e4bafa310d6..50036459328 100644
> --- a/gcc/flags.h
> +++ b/gcc/flags.h
> @@ -53,6 +53,10 @@ extern bool btf_with_core_debuginfo_p ();
>
>  extern bool ctf_debuginfo_p ();
>
> +/* Return true iff CodeView debug info is enabled.  */
> +
> +extern bool codeview_debuginfo_p ();
> +
>  /* Return true iff DWARF2 debug info is enabled.  */
>
>  extern bool dwarf_debuginfo_p (struct gcc_options *opts = &global_options);
> diff --git a/gcc/opts.cc b/gcc/opts.cc
> index 8015cb7556a..f02101ceea3 100644
> --- a/gcc/opts.cc
> +++ b/gcc/opts.cc
> @@ -50,7 +50,7 @@ static void set_Wstrict_aliasing (struct gcc_options *opts, int onoff);
>
>  const char *const debug_type_names[] =
>  {
> -  "none", "dwarf-2", "vms", "ctf", "btf"
> +  "none", "dwarf-2", "vms", "ctf", "btf", "codeview"
>  };
>
>  /* Bitmasks of fundamental debug info formats indexed by enum
> @@ -59,13 +59,13 @@ const char *const debug_type_names[] =
>  static uint32_t debug_type_masks[] =
>  {
>    NO_DEBUG, DWARF2_DEBUG, VMS_DEBUG,
> -  CTF_DEBUG, BTF_DEBUG
> +  CTF_DEBUG, BTF_DEBUG, CODEVIEW_DEBUG
>  };
>
>  /* Names of the set of debug formats requested by user.  Updated and accessed
>     via debug_set_names.  */
>
> -static char df_set_names[sizeof "none dwarf-2 vms ctf btf"];
> +static char df_set_names[sizeof "none dwarf-2 vms ctf btf codeview"];
>
>  /* Get enum debug_info_type of the specified debug format, for error messages.
>     Can be used only for individual debug format types.  */
> @@ -159,6 +159,14 @@ ctf_debuginfo_p ()
>    return (write_symbols & CTF_DEBUG);
>  }
>
> +/* Return TRUE iff CodeView debug info is enabled.  */
> +
> +bool
> +codeview_debuginfo_p ()
> +{
> +  return (write_symbols & CODEVIEW_DEBUG);
> +}
> +
>  /* Return TRUE iff dwarf2 debug info is enabled.  */
>
>  bool
> @@ -173,7 +181,8 @@ dwarf_debuginfo_p (struct gcc_options *opts)
>  bool dwarf_based_debuginfo_p ()
>  {
>    return ((write_symbols & CTF_DEBUG)
> -         || (write_symbols & BTF_DEBUG));
> +         || (write_symbols & BTF_DEBUG)
> +         || (write_symbols & CODEVIEW_DEBUG));
>  }
>
>  /* All flag uses below need to explicitely reference the option sets
> @@ -3145,6 +3154,9 @@ common_handle_option (struct gcc_options *opts,
>        break;
>
>      case OPT_gcodeview:
> +      set_debug_level (CODEVIEW_DEBUG, false, arg, opts, opts_set, loc);
> +      if (opts->x_debug_info_level < DINFO_LEVEL_NORMAL)
> +       opts->x_debug_info_level = DINFO_LEVEL_NORMAL;
>        break;
>
>      case OPT_gbtf:
> @@ -3419,7 +3431,8 @@ set_debug_level (uint32_t dinfo, int extended, const char *arg,
>             warning_at (loc, 0, "target system does not support debug output");
>         }
>        else if ((opts->x_write_symbols & CTF_DEBUG)
> -              || (opts->x_write_symbols & BTF_DEBUG))
> +              || (opts->x_write_symbols & BTF_DEBUG)
> +              || (opts->x_write_symbols & CODEVIEW_DEBUG))
>         {
>           opts->x_write_symbols |= DWARF2_DEBUG;
>           opts_set->x_write_symbols |= DWARF2_DEBUG;
> diff --git a/gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c b/gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c
> new file mode 100644
> index 00000000000..eb5f14530dc
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/debug/codeview/codeview-1.c
> @@ -0,0 +1,6 @@
> +/* { dg-do compile } */
> +/* { dg-options "-gcodeview" } */
> +
> +void func(void)
> +{
> +}
> diff --git a/gcc/testsuite/gcc.dg/debug/codeview/codeview.exp b/gcc/testsuite/gcc.dg/debug/codeview/codeview.exp
> new file mode 100644
> index 00000000000..ff705a4ae78
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/debug/codeview/codeview.exp
> @@ -0,0 +1,48 @@
> +#   Copyright (C) 2023 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with GCC; see the file COPYING3.  If not see
> +# <http://www.gnu.org/licenses/>.
> +
> +# GCC testsuite that uses the `dg.exp' driver.
> +
> +# Load support procs.
> +load_lib gcc-dg.exp
> +
> +if {![istarget i*86-*-mingw*]
> +  && ![istarget x86_64-*-mingw*]} {
> +    return 0
> +}
> +
> +# If a testcase doesn't have special options, use these.
> +global DEFAULT_CFLAGS
> +if ![info exists DEFAULT_CFLAGS] then {
> +    set DEFAULT_CFLAGS " -ansi -pedantic-errors"
> +}
> +
> +# Initialize `dg'.
> +dg-init
> +
> +# Main loop.
> +set comp_output [gcc_target_compile \
> +    "$srcdir/$subdir/../trivial.c" "trivial.S" assembly \
> +    "additional_flags=-gcodeview"]
> +if { ! [string match "*: target system does not support the * debug format*" \
> +    $comp_output] } {
> +    remove-build-file "trivial.S"
> +    dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.\[cS\] ]] \
> +           "" $DEFAULT_CFLAGS
> +}
> +
> +# All done.
> +dg-finish
> diff --git a/gcc/toplev.cc b/gcc/toplev.cc
> index 8af9bf5090e..862583df0f4 100644
> --- a/gcc/toplev.cc
> +++ b/gcc/toplev.cc
> @@ -1431,6 +1431,10 @@ process_options (bool no_backend)
>  #ifdef DWARF2_LINENO_DEBUGGING_INFO
>    else if (write_symbols == DWARF2_DEBUG)
>      debug_hooks = &dwarf2_lineno_debug_hooks;
> +#endif
> +#ifdef CODEVIEW_DEBUGGING_INFO
> +  else if (codeview_debuginfo_p ())
> +    debug_hooks = &dwarf2_debug_hooks;
>  #endif
>    else
>      {
> --
> 2.41.0
>

Re: [PATCH 2/5] Support for CodeView debugging format

[Mark Harmstone]

On 26/10/23 10:35, Richard Biener wrote:
> On Mon, Oct 23, 2023 at 2:57 AM Mark Harmstone <mark@harmstone.com> wrote:
>>
>> This patch and the following add initial support for Microsoft's
>> CodeView debugging format, as used by MSVC, to mingw targets.
> 
> A high-level question - it seems there's almost no information in the
> codeview sections,
> so is that debug format even inferior to STABS?  Is it even used with
> contemporary
> toolchains or is DWARF a thing with MSVC?

This isn't comprehensive, I'm just adding line number info first. CodeView is as
fully featured as DWARF.

> If CodeView is as full-featured as DWARF you are going to run into issues with
> how we handle LTO given at dwarf2out_finish time all the DWARF for types and
> declarations is "gone" (to disk).  For that post-processing the binary would be
> much easier.

Thanks, I'll bear that in mind once I get to coding the bits for type declarations.
Types are stored in the .debug$T section, as opposed to the .debug$S section dealt
with here, so it might turn out that we'll need to deal with the two sections in
different ways.

Mark