[PATCH] gas: Add --gcodeview option

[PATCH] gas: Add --gcodeview option

[Mark Harmstone]

This patch adds a --gcodeview option to as, which causes it to emit a
.debug$S section with line number details in Microsoft's CodeView
format. My upcoming PDB patches to ld will parse these so they can be
read by windbg etc.

As with the PDB files, you can use Microsoft's cvdump.exe if you're
interested in seeing a textual representation of what exactly this is emitting.

---
 gas/Makefile.am                         |   2 +
 gas/Makefile.in                         |   9 +-
 gas/as.c                                |  17 +
 gas/as.h                                |   3 +-
 gas/codeview.c                          | 541 ++++++++++++++++++++++++
 gas/codeview.h                          | 104 +++++
 gas/read.c                              |   4 +
 gas/testsuite/gas/i386/codeview-lines.d |   9 +
 gas/testsuite/gas/i386/codeview.exp     | 324 ++++++++++++++
 gas/testsuite/gas/i386/codeview1.s      |   7 +
 gas/testsuite/gas/i386/codeview2.s      |   2 +
 11 files changed, 1018 insertions(+), 4 deletions(-)
 create mode 100644 gas/codeview.c
 create mode 100644 gas/codeview.h
 create mode 100644 gas/testsuite/gas/i386/codeview-lines.d
 create mode 100644 gas/testsuite/gas/i386/codeview.exp
 create mode 100644 gas/testsuite/gas/i386/codeview1.s
 create mode 100644 gas/testsuite/gas/i386/codeview2.s

diff --git a/gas/Makefile.am b/gas/Makefile.am
index 5f0f24abf8d..b83c14f3a3f 100644
--- a/gas/Makefile.am
+++ b/gas/Makefile.am
@@ -68,6 +68,7 @@ GAS_CFILES = \
 	app.c \
 	as.c \
 	atof-generic.c \
+	codeview.c \
 	compress-debug.c \
 	cond.c \
 	depend.c \
@@ -104,6 +105,7 @@ HFILES = \
 	bignum.h \
 	bit_fix.h \
 	cgen.h \
+	codeview.h \
 	compress-debug.h \
 	dwarf2dbg.h \
 	dw2gencfi.h \
diff --git a/gas/Makefile.in b/gas/Makefile.in
index 5a4dd702252..94bb8d1a54a 100644
--- a/gas/Makefile.in
+++ b/gas/Makefile.in
@@ -162,9 +162,9 @@ CONFIG_CLEAN_FILES = gdb.ini .gdbinit po/Makefile.in
 CONFIG_CLEAN_VPATH_FILES =
 PROGRAMS = $(noinst_PROGRAMS)
 am__objects_1 = app.$(OBJEXT) as.$(OBJEXT) atof-generic.$(OBJEXT) \
-	compress-debug.$(OBJEXT) cond.$(OBJEXT) depend.$(OBJEXT) \
-	dwarf2dbg.$(OBJEXT) dw2gencfi.$(OBJEXT) ecoff.$(OBJEXT) \
-	ehopt.$(OBJEXT) expr.$(OBJEXT) flonum-copy.$(OBJEXT) \
+	codeview.$(OBJEXT) compress-debug.$(OBJEXT) cond.$(OBJEXT) \
+	depend.$(OBJEXT) dwarf2dbg.$(OBJEXT) dw2gencfi.$(OBJEXT) \
+	ecoff.$(OBJEXT) ehopt.$(OBJEXT) expr.$(OBJEXT) flonum-copy.$(OBJEXT) \
 	flonum-konst.$(OBJEXT) flonum-mult.$(OBJEXT) frags.$(OBJEXT) \
 	hash.$(OBJEXT) input-file.$(OBJEXT) input-scrub.$(OBJEXT) \
 	listing.$(OBJEXT) literal.$(OBJEXT) macro.$(OBJEXT) \
@@ -554,6 +554,7 @@ GAS_CFILES = \
 	app.c \
 	as.c \
 	atof-generic.c \
+	codeview.c \
 	compress-debug.c \
 	cond.c \
 	depend.c \
@@ -589,6 +590,7 @@ HFILES = \
 	bignum.h \
 	bit_fix.h \
 	cgen.h \
+	codeview.h \
 	compress-debug.h \
 	dwarf2dbg.h \
 	dw2gencfi.h \
@@ -1290,6 +1292,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/as.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/atof-generic.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/cgen.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/codeview.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/compress-debug.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/cond.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/depend.Po@am__quote@
diff --git a/gas/as.c b/gas/as.c
index d42dd5394b5..792c06be6f5 100644
--- a/gas/as.c
+++ b/gas/as.c
@@ -42,6 +42,7 @@
 #include "macro.h"
 #include "dwarf2dbg.h"
 #include "dw2gencfi.h"
+#include "codeview.h"
 #include "bfdver.h"
 #include "write.h"
 
@@ -331,6 +332,10 @@ Options:\n\
   --gdwarf-cie-version=<N> generate version 1, 3 or 4 DWARF CIEs\n"));
   fprintf (stream, _("\
   --gdwarf-sections       generate per-function section names for DWARF line information\n"));
+#ifdef TE_PE
+  fprintf (stream, _("\
+  --gcodeview             generate CodeView debugging information\n"));
+#endif
   fprintf (stream, _("\
   --hash-size=<N>         ignored\n"));
   fprintf (stream, _("\
@@ -481,6 +486,7 @@ parse_args (int * pargc, char *** pargv)
       OPTION_GDWARF_5,
       OPTION_GDWARF_SECTIONS, /* = STD_BASE + 20 */
       OPTION_GDWARF_CIE_VERSION,
+      OPTION_GCODEVIEW,
       OPTION_STRIP_LOCAL_ABSOLUTE,
       OPTION_TRADITIONAL_FORMAT,
       OPTION_WARN,
@@ -541,6 +547,9 @@ parse_args (int * pargc, char *** pargv)
     ,{"gdwarf2", no_argument, NULL, OPTION_GDWARF_2}
     ,{"gdwarf-sections", no_argument, NULL, OPTION_GDWARF_SECTIONS}
     ,{"gdwarf-cie-version", required_argument, NULL, OPTION_GDWARF_CIE_VERSION}
+#ifdef TE_PE
+    ,{"gcodeview", no_argument, NULL, OPTION_GCODEVIEW}
+#endif
     ,{"gen-debug", no_argument, NULL, 'g'}
     ,{"gstabs", no_argument, NULL, OPTION_GSTABS}
     ,{"gstabs+", no_argument, NULL, OPTION_GSTABS_PLUS}
@@ -866,6 +875,12 @@ This program has absolutely no warranty.\n"));
 	  flag_dwarf_sections = true;
 	  break;
 
+#ifdef TE_PE
+	case OPTION_GCODEVIEW:
+	  debug_type = DEBUG_CODEVIEW;
+	  break;
+#endif
+
         case OPTION_GDWARF_CIE_VERSION:
 	  flag_dwarf_cie_version = atoi (optarg);
           /* The available CIE versions are 1 (DWARF 2), 3 (DWARF 3), and 4
@@ -1421,6 +1436,8 @@ main (int argc, char ** argv)
     }
 #endif
 
+  codeview_finish ();
+
   /* If we've been collecting dwarf2 .debug_line info, either for
      assembly debugging or on behalf of the compiler, emit it now.  */
   dwarf2_finish ();
diff --git a/gas/as.h b/gas/as.h
index 730e134dce6..b8d3c49cae2 100644
--- a/gas/as.h
+++ b/gas/as.h
@@ -381,7 +381,8 @@ enum debug_info_type
   DEBUG_STABS,
   DEBUG_ECOFF,
   DEBUG_DWARF,
-  DEBUG_DWARF2
+  DEBUG_DWARF2,
+  DEBUG_CODEVIEW
 };
 
 extern enum debug_info_type debug_type;
diff --git a/gas/codeview.c b/gas/codeview.c
new file mode 100644
index 00000000000..da7145659f5
--- /dev/null
+++ b/gas/codeview.c
@@ -0,0 +1,541 @@
+/* codeview.c - CodeView debug support
+   Copyright (C) 2022 Free Software Foundation, Inc.
+
+   This file is part of GAS, the GNU Assembler.
+
+   GAS 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.
+
+   GAS 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 GAS; see the file COPYING.  If not, write to the Free
+   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+#include "as.h"
+#include "codeview.h"
+#include "subsegs.h"
+#include "filenames.h"
+#include "md5.h"
+
+#ifdef TE_PE
+
+#define NUM_MD5_BYTES       	16
+
+#define FILE_ENTRY_PADDING	2
+#define FILE_ENTRY_LENGTH	(sizeof (struct file_checksum) + NUM_MD5_BYTES \
+				 + FILE_ENTRY_PADDING)
+
+struct line
+{
+  struct line *next;
+  unsigned int lineno;
+  addressT frag_offset;
+};
+
+struct line_file
+{
+  struct line_file *next;
+  unsigned int fileno;
+  struct line *lines_head, *lines_tail;
+  unsigned int num_lines;
+};
+
+struct line_block
+{
+  struct line_block *next;
+  segT seg;
+  unsigned int subseg;
+  fragS *frag;
+  symbolS *sym;
+  struct line_file *files_head, *files_tail;
+};
+
+struct source_file
+{
+  struct source_file *next;
+  unsigned int num;
+  char *filename;
+  uint32_t string_pos;
+  uint8_t md5[NUM_MD5_BYTES];
+};
+
+static struct line_block *blocks_head = NULL, *blocks_tail = NULL;
+static struct source_file *files_head = NULL, *files_tail = NULL;
+static unsigned int num_source_files = 0;
+
+/* Return the size of the current fragment (taken from dwarf2dbg.c).  */
+static offsetT
+get_frag_fix (fragS *frag, segT seg)
+{
+  frchainS *fr;
+
+  if (frag->fr_next)
+    return frag->fr_fix;
+
+  for (fr = seg_info (seg)->frchainP; fr; fr = fr->frch_next)
+    if (fr->frch_last == frag)
+      return (char *) obstack_next_free (&fr->frch_obstack) - frag->fr_literal;
+
+  abort ();
+}
+
+/* Emit a .secrel32 relocation.  */
+static void
+emit_secrel32_reloc (symbolS *sym)
+{
+  expressionS exp;
+
+  memset (&exp, 0, sizeof (exp));
+  exp.X_op = O_secrel;
+  exp.X_add_symbol = sym;
+  exp.X_add_number = 0;
+  emit_expr (&exp, sizeof (uint32_t));
+}
+
+/* Emit a .secidx relocation.  */
+static void
+emit_secidx_reloc (symbolS *sym)
+{
+  expressionS exp;
+
+  memset (&exp, 0, sizeof (exp));
+  exp.X_op = O_secidx;
+  exp.X_add_symbol = sym;
+  exp.X_add_number = 0;
+  emit_expr (&exp, sizeof (uint16_t));
+}
+
+/* Write the DEBUG_S_STRINGTABLE subsection.  */
+static void
+write_string_table (void)
+{
+  uint32_t len;
+  unsigned int padding;
+  char *ptr, *start;
+
+  len = 1;
+
+  for (struct source_file *sf = files_head; sf; sf = sf->next)
+    {
+      len += strlen (sf->filename) + 1;
+    }
+
+  if (len % 4)
+    padding = 4 - (len % 4);
+  else
+    padding = 0;
+
+  ptr = frag_more (sizeof (uint32_t) + sizeof (uint32_t) + len + padding);
+
+  bfd_putl32 (DEBUG_S_STRINGTABLE, ptr);
+  ptr += sizeof (uint32_t);
+  bfd_putl32 (len, ptr);
+  ptr += sizeof (uint32_t);
+
+  start = ptr;
+
+  *ptr = 0;
+  ptr++;
+
+  for (struct source_file *sf = files_head; sf; sf = sf->next)
+    {
+      size_t fn_len = strlen (sf->filename);
+
+      sf->string_pos = ptr - start;
+
+      memcpy(ptr, sf->filename, fn_len + 1);
+      ptr += fn_len + 1;
+    }
+
+  memset (ptr, 0, padding);
+}
+
+/* Write the DEBUG_S_FILECHKSMS subsection.  */
+static void
+write_checksums (void)
+{
+  uint32_t len;
+  char *ptr;
+
+  len = FILE_ENTRY_LENGTH * num_source_files;
+
+  ptr = frag_more (sizeof (uint32_t) + sizeof (uint32_t) + len);
+
+  bfd_putl32 (DEBUG_S_FILECHKSMS, ptr);
+  ptr += sizeof (uint32_t);
+  bfd_putl32 (len, ptr);
+  ptr += sizeof (uint32_t);
+
+  for (struct source_file *sf = files_head; sf; sf = sf->next)
+    {
+      struct file_checksum fc;
+
+      fc.file_id = sf->string_pos;
+      fc.checksum_length = NUM_MD5_BYTES;
+      fc.checksum_type = CHKSUM_TYPE_MD5;
+
+      memcpy (ptr, &fc, sizeof (struct file_checksum));
+      ptr += sizeof (struct file_checksum);
+
+      memcpy (ptr, sf->md5, NUM_MD5_BYTES);
+      ptr += NUM_MD5_BYTES;
+
+      memset (ptr, 0, FILE_ENTRY_PADDING);
+      ptr += FILE_ENTRY_PADDING;
+    }
+}
+
+/* Write the DEBUG_S_LINES subsection.  */
+static void
+write_lines_info (void)
+{
+  while (blocks_head)
+    {
+      struct line_block *lb;
+      struct line_file *lf;
+      uint32_t len;
+      uint32_t off;
+      char *ptr;
+
+      lb = blocks_head;
+
+      bfd_putl32 (DEBUG_S_LINES, frag_more (sizeof (uint32_t)));
+
+      len = sizeof (struct cv_lines_header);
+
+      for (lf = lb->files_head; lf; lf = lf->next)
+	{
+	  len += sizeof (struct cv_lines_block);
+	  len += sizeof (struct cv_line) * lf->num_lines;
+	}
+
+      bfd_putl32 (len, frag_more (sizeof (uint32_t)));
+
+      /* Write the header (struct cv_lines_header).  We can't use a struct
+	 for this as we're also emitting relocations.  */
+
+      emit_secrel32_reloc (lb->sym);
+      emit_secidx_reloc (lb->sym);
+
+      ptr = frag_more (len - sizeof (uint32_t) - sizeof (uint16_t));
+
+      /* Flags */
+      bfd_putl16 (0, ptr);
+      ptr += sizeof (uint16_t);
+
+      off = lb->files_head->lines_head->frag_offset;
+
+      /* Length of region */
+      bfd_putl32 (get_frag_fix (lb->frag, lb->seg) - off, ptr);
+      ptr += sizeof (uint32_t);
+
+      while (lb->files_head)
+	{
+	  struct cv_lines_block *block = (struct cv_lines_block *) ptr;
+
+	  lf = lb->files_head;
+
+	  bfd_putl32(lf->fileno * FILE_ENTRY_LENGTH, &block->file_id);
+	  bfd_putl32(lf->num_lines, &block->num_lines);
+	  bfd_putl32(sizeof (struct cv_lines_block)
+		     + (sizeof (struct cv_line) * lf->num_lines),
+		     &block->length);
+
+	  ptr += sizeof (struct cv_lines_block);
+
+	  while (lf->lines_head)
+	    {
+	      struct line *l;
+	      struct cv_line *l2 = (struct cv_line *) ptr;
+
+	      l = lf->lines_head;
+
+	      /* Only the bottom 24 bits of line_no actually encode the
+		 line number.  The top bit is a flag meaning "is
+		 a statement".  */
+
+	      bfd_putl32 (l->frag_offset - off, &l2->offset);
+	      bfd_putl32 (0x80000000 | (l->lineno & 0xffffff),
+			  &l2->line_no);
+
+	      lf->lines_head = l->next;
+
+	      free(l);
+
+	      ptr += sizeof (struct cv_line);
+	    }
+
+	  lb->files_head = lf->next;
+	  free (lf);
+	}
+
+      blocks_head = lb->next;
+
+      free (lb);
+    }
+}
+
+/* Return the CodeView constant for the selected architecture.  */
+static uint16_t
+target_processor (void)
+{
+  if (stdoutput->arch_info->arch != bfd_arch_i386)
+    return 0;
+
+  if (stdoutput->arch_info->mach & bfd_mach_x86_64)
+    return CV_CFL_X64;
+  else
+    return CV_CFL_80386;
+}
+
+/* Write the CodeView symbols, describing the object name and
+   assembler version.  */
+static void
+write_symbols_info (void)
+{
+  static const char assembler[] = "GNU AS " VERSION;
+
+  char *path = lrealpath (out_file_name);
+  char *path2 = remap_debug_filename (path);
+  size_t path_len, padding;
+  uint32_t len;
+  struct OBJNAMESYM objname;
+  struct COMPILESYM3 compile3;
+  char *ptr;
+
+  free (path);
+  path = path2;
+
+  path_len = strlen (path);
+
+  len = sizeof (struct OBJNAMESYM) + path_len + 1;
+  len += sizeof (struct COMPILESYM3) + sizeof (assembler);
+
+  if (len % 4)
+    padding = 4 - (len % 4);
+  else
+    padding = 0;
+
+  len += padding;
+
+  ptr = frag_more (sizeof (uint32_t) + sizeof (uint32_t) + len);
+
+  bfd_putl32 (DEBUG_S_SYMBOLS, ptr);
+  ptr += sizeof (uint32_t);
+  bfd_putl32 (len, ptr);
+  ptr += sizeof (uint32_t);
+
+  /* Write S_OBJNAME entry.  */
+
+  bfd_putl16 (sizeof (struct OBJNAMESYM) - sizeof (uint16_t) + path_len + 1,
+	      &objname.length);
+  bfd_putl16 (S_OBJNAME, &objname.type);
+  bfd_putl32 (0, &objname.signature);
+
+  memcpy (ptr, &objname, sizeof (struct OBJNAMESYM));
+  ptr += sizeof (struct OBJNAMESYM);
+  memcpy (ptr, path, path_len + 1);
+  ptr += path_len + 1;
+
+  free (path);
+
+  /* Write S_COMPILE3 entry.  */
+
+  bfd_putl16 (sizeof (struct COMPILESYM3) - sizeof (uint16_t)
+	      + sizeof (assembler) + padding, &compile3.length);
+  bfd_putl16 (S_COMPILE3, &compile3.type);
+  bfd_putl32 (CV_CFL_MASM, &compile3.flags);
+  bfd_putl16 (target_processor (), &compile3.machine);
+  bfd_putl16 (0, &compile3.frontend_major);
+  bfd_putl16 (0, &compile3.frontend_minor);
+  bfd_putl16 (0, &compile3.frontend_build);
+  bfd_putl16 (0, &compile3.frontend_qfe);
+  bfd_putl16 (0, &compile3.backend_major);
+  bfd_putl16 (0, &compile3.backend_minor);
+  bfd_putl16 (0, &compile3.backend_build);
+  bfd_putl16 (0, &compile3.backend_qfe);
+
+  memcpy (ptr, &compile3, sizeof (struct COMPILESYM3));
+  ptr += sizeof (struct COMPILESYM3);
+  memcpy (ptr, assembler, sizeof (assembler));
+  ptr += sizeof (assembler);
+
+  memset (ptr, 0, padding);
+}
+
+/* Processing of the file has finished, emit the .debug$S section.  */
+void
+codeview_finish (void)
+{
+  segT seg;
+
+  if (!blocks_head)
+    return;
+
+  seg = subseg_new (".debug$S", 0);
+
+  bfd_set_section_flags (seg, SEC_READONLY | SEC_NEVER_LOAD);
+
+  bfd_putl32 (CV_SIGNATURE_C13, frag_more (sizeof (uint32_t)));
+
+  write_string_table ();
+  write_checksums ();
+  write_lines_info ();
+  write_symbols_info ();
+}
+
+/* Assign a new index number for the given file, or return the existing
+   one if already assigned.  */
+static unsigned int
+get_fileno (const char *file)
+{
+  struct source_file *sf;
+  char *path = lrealpath (file);
+  char *path2 = remap_debug_filename (path);
+  size_t path_len;
+  FILE *f;
+
+  free (path);
+  path = path2;
+
+  path_len = strlen (path);
+
+  for (sf = files_head; sf; sf = sf->next)
+    {
+      if (path_len == strlen (sf->filename)
+	  && !filename_ncmp (sf->filename, path, path_len))
+	{
+	  free (path);
+	  return sf->num;
+	}
+    }
+
+  sf = xmalloc (sizeof (struct source_file));
+
+  sf->next = NULL;
+  sf->num = num_source_files;
+  sf->filename = path;
+
+  f = fopen (file, "r");
+  if (!f)
+    as_fatal (_("could not open %s for reading"), file);
+
+  if (md5_stream (f, sf->md5))
+    {
+      fclose(f);
+      as_fatal (_("md5_stream failed"));
+    }
+
+  fclose(f);
+
+  if (!files_head)
+    files_head = sf;
+  else
+    files_tail->next = sf;
+
+  files_tail = sf;
+
+  num_source_files++;
+
+  return num_source_files - 1;
+}
+
+/* Called for each new line in asm file.  */
+void
+codeview_generate_asm_lineno (void)
+{
+  const char *file;
+  unsigned int fileno;
+  unsigned int lineno;
+  struct line *l;
+  symbolS *sym = NULL;
+  struct line_block *lb;
+  struct line_file *lf;
+
+  file = as_where (&lineno);
+
+  fileno = get_fileno (file);
+
+  if (!blocks_tail || blocks_tail->frag != frag_now)
+    {
+      static int label_num = 0;
+      char name[32];
+
+      sprintf (name, ".Loc.%u", label_num);
+      label_num++;
+      sym = symbol_new (name, now_seg, frag_now, frag_now_fix ());
+
+      lb = xmalloc (sizeof (struct line_block));
+      lb->next = NULL;
+      lb->seg = now_seg;
+      lb->subseg = now_subseg;
+      lb->frag = frag_now;
+      lb->sym = sym;
+      lb->files_head = lb->files_tail = NULL;
+
+      if (!blocks_head)
+	blocks_head = lb;
+      else
+	blocks_tail->next = lb;
+
+      blocks_tail = lb;
+    }
+  else
+    {
+      lb = blocks_tail;
+    }
+
+  if (!lb->files_tail || lb->files_tail->fileno != fileno)
+    {
+      lf = xmalloc (sizeof (struct line_file));
+      lf->next = NULL;
+      lf->fileno = fileno;
+      lf->lines_head = lf->lines_tail = NULL;
+      lf->num_lines = 0;
+
+      if (!lb->files_head)
+	lb->files_head = lf;
+      else
+	lb->files_tail->next = lf;
+
+      lb->files_tail = lf;
+    }
+  else
+    {
+      lf = lb->files_tail;
+    }
+
+  l = xmalloc (sizeof (struct line));
+  l->next = NULL;
+  l->lineno = lineno;
+  l->frag_offset = frag_now_fix ();
+
+  if (!lf->lines_head)
+    lf->lines_head = l;
+  else
+    lf->lines_tail->next = l;
+
+  lf->lines_tail = l;
+  lf->num_lines++;
+}
+
+#else
+
+void
+codeview_finish (void)
+{
+}
+
+void
+codeview_generate_asm_lineno (void)
+{
+}
+
+#endif /* TE_PE */
diff --git a/gas/codeview.h b/gas/codeview.h
new file mode 100644
index 00000000000..49272b6be9a
--- /dev/null
+++ b/gas/codeview.h
@@ -0,0 +1,104 @@
+/* codeview.h - CodeView debug support
+   Copyright (C) 2022 Free Software Foundation, Inc.
+
+   This file is part of GAS, the GNU Assembler.
+
+   GAS 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.
+
+   GAS 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 GAS; see the file COPYING.  If not, write to the Free
+   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+/* Header files referred to below can be found in Microsoft's PDB
+   repository: https://github.com/microsoft/microsoft-pdb.  */
+
+#ifndef GAS_CODEVIEW_H
+#define GAS_CODEVIEW_H
+
+#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 S_OBJNAME		0x1101
+#define S_COMPILE3		0x113c
+
+#define CV_CFL_MASM		0x03
+
+#define CV_CFL_80386		0x03
+#define CV_CFL_X64		0xD0
+
+#define CHKSUM_TYPE_MD5		1
+
+/* OBJNAMESYM in cvinfo.h */
+struct OBJNAMESYM
+{
+  uint16_t length;
+  uint16_t type;
+  uint32_t signature;
+};
+
+/* COMPILESYM3 in 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;
+
+/* filedata in dumpsym7.cpp */
+struct file_checksum
+{
+  uint32_t file_id;
+  uint8_t checksum_length;
+  uint8_t checksum_type;
+} ATTRIBUTE_PACKED;
+
+/* CV_DebugSLinesHeader_t in cvinfo.h */
+struct cv_lines_header
+{
+  uint32_t offset;
+  uint16_t section;
+  uint16_t flags;
+  uint32_t length;
+};
+
+/* CV_DebugSLinesFileBlockHeader_t in cvinfo.h */
+struct cv_lines_block
+{
+  uint32_t file_id;
+  uint32_t num_lines;
+  uint32_t length;
+};
+
+/* CV_Line_t in cvinfo.h */
+struct cv_line
+{
+  uint32_t offset;
+  uint32_t line_no;
+};
+
+extern void codeview_finish (void);
+extern void codeview_generate_asm_lineno (void);
+
+#endif
diff --git a/gas/read.c b/gas/read.c
index e23be666dde..17971db9df7 100644
--- a/gas/read.c
+++ b/gas/read.c
@@ -38,6 +38,7 @@
 #include "obstack.h"
 #include "ecoff.h"
 #include "dw2gencfi.h"
+#include "codeview.h"
 #include "wchar.h"
 
 #include <limits.h>
@@ -5965,6 +5966,9 @@ generate_lineno_debug (void)
 	 support that is required (calling dwarf2_emit_insn), we
 	 let dwarf2dbg.c call as_where on its own.  */
       break;
+    case DEBUG_CODEVIEW:
+      codeview_generate_asm_lineno ();
+      break;
     }
 }
 
diff --git a/gas/testsuite/gas/i386/codeview-lines.d b/gas/testsuite/gas/i386/codeview-lines.d
new file mode 100644
index 00000000000..68b279ee7af
--- /dev/null
+++ b/gas/testsuite/gas/i386/codeview-lines.d
@@ -0,0 +1,9 @@
+
+tmpdir/codeview-lines:     file format binary
+
+Contents of section .data:
+ 0000 00000000 00000000 04000000 00000000  ................
+ 0010 01000000 14000000 00000000 05000080  ................
+ 0020 18000000 02000000 1c000000 01000000  ................
+ 0030 01000080 02000000 02000080 00000000  ................
+ 0040 01000000 14000000 03000000 07000080  ................
diff --git a/gas/testsuite/gas/i386/codeview.exp b/gas/testsuite/gas/i386/codeview.exp
new file mode 100644
index 00000000000..ed606c1d5d4
--- /dev/null
+++ b/gas/testsuite/gas/i386/codeview.exp
@@ -0,0 +1,324 @@
+# Copyright (C) 2022 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 this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+
+if { ![istarget "i*86-*-*"] && ![istarget "x86_64-*-*"] } then {
+    return
+}
+
+if { ![istarget "*-*-cygwin*"] && ![istarget "*-*-pe"]
+      && ![istarget "*-*-mingw*"] } then {
+    return
+}
+
+proc read_subsection { fi } {
+    set data [read $fi 4]
+    binary scan $data i type
+
+    set data [read $fi 4]
+    binary scan $data i len
+
+    set data [read $fi $len]
+
+    if { [expr $len % 4] != 0 } {
+	seek $fi [expr 4 - ($len % 4)] current
+    }
+
+    return [list $type $data]
+}
+
+proc check_file_checksums { chksums string_table } {
+    set off 0
+
+    # check first file
+
+    set data [string range $chksums $off [expr $off + 3]]
+    incr off 4
+    binary scan $data i string_off
+
+    set filename [string range $string_table $string_off [expr [string first \000 $string_table $string_off] - 1]]
+
+    if ![string match "*codeview1.s" $filename] {
+	fail "Incorrect filename for first source file"
+    } else {
+	pass "Correct filename for first source file"
+    }
+
+    set data [string range $chksums $off $off]
+    incr off
+    binary scan $data c hash_length
+
+    if { $hash_length != 16 } {
+	fail "Incorrect hash length"
+    } else {
+	pass "Correct hash length"
+    }
+
+    set data [string range $chksums $off $off]
+    incr off
+    binary scan $data c hash_type
+
+    if { $hash_type != 1 } {
+	fail "Incorrect hash type"
+    } else {
+	pass "Correct hash type"
+    }
+
+    set data [string range $chksums $off [expr $off + $hash_length - 1]]
+    incr off $hash_length
+    binary scan $data H* hash
+
+    if ![string equal $hash "5ddeeb7d506f830e5f56bb2eb43ad407"] {
+	fail "Incorrect MD5 hash"
+    } else {
+	pass "Correct MD5 hash"
+    }
+
+    # skip padding
+    if { [expr $off % 4] != 0 } {
+	incr off [expr 4 - ($off % 4)]
+    }
+
+    # check second file
+
+    set data [string range $chksums $off [expr $off + 3]]
+    incr off 4
+    binary scan $data i string_off
+
+    set filename [string range $string_table $string_off [expr [string first \000 $string_table $string_off] - 1]]
+
+    if ![string match "*codeview2.s" $filename] {
+	fail "Incorrect filename for second source file"
+    } else {
+	pass "Correct filename for second source file"
+    }
+
+    set data [string range $chksums $off $off]
+    incr off
+    binary scan $data c hash_length
+
+    if { $hash_length != 16 } {
+	fail "Incorrect hash length"
+    } else {
+	pass "Correct hash length"
+    }
+
+    set data [string range $chksums $off $off]
+    incr off
+    binary scan $data c hash_type
+
+    if { $hash_type != 1 } {
+	fail "Incorrect hash type"
+    } else {
+	pass "Correct hash type"
+    }
+
+    set data [string range $chksums $off [expr $off + $hash_length - 1]]
+    incr off $hash_length
+    binary scan $data H* hash
+
+    if ![string equal $hash "2fbd11b8193e62ec93d50b04dfb352a8"] {
+	fail "Incorrect MD5 hash"
+    } else {
+	pass "Correct MD5 hash"
+    }
+}
+
+proc check_lines { lines } {
+    global OBJDUMP
+    global srcdir
+    global subdir
+
+    set fi [open tmpdir/codeview-lines w]
+    fconfigure $fi -translation binary
+    puts -nonewline $fi $lines
+    close $fi
+
+    gas_host_run "$OBJDUMP -s --target=binary tmpdir/codeview-lines" ">& tmpdir/codeview-lines-text"
+
+    set exp [file_contents "$srcdir/$subdir/codeview-lines.d"]
+    set got [file_contents "tmpdir/codeview-lines-text"]
+
+    if [string equal $exp $got] {
+	pass "Correct lines info"
+    } else {
+	fail "Incorrect lines info"
+    }
+}
+
+proc check_objname { sym } {
+    binary scan $sym s type
+
+    if { $type != 0x1101 } {
+	fail "Symbol was not S_OBJNAME"
+	return
+    } else {
+	pass "Symbol was S_OBJNAME"
+    }
+
+    binary scan [string range $sym 2 5] i signature
+
+    if { $signature != 0 } {
+	fail "S_OBJNAME signature was not 0"
+	return
+    } else {
+	pass "S_OBJNAME signature was 0"
+    }
+
+    set filename [string range $sym 6 [expr [string first \000 $sym 6] - 1]]
+
+    if ![string match "*codeview1.o" $filename] {
+	fail "Incorrect object name in S_OBJNAME"
+    } else {
+	pass "Correct object name in S_OBJNAME"
+    }
+}
+
+proc check_compile3 { sym } {
+    binary scan $sym s type
+
+    if { $type != 0x113c } {
+	fail "Symbol was not S_COMPILE3"
+	return
+    } else {
+	pass "Symbol was S_COMPILE3"
+    }
+
+    set assembler_name [string range $sym 24 [expr [string first \000 $sym 24] - 1]]
+
+    if ![string match "GNU AS *" $assembler_name] {
+	fail "Incorrect assembler name"
+    } else {
+	pass "Correct assembler name"
+    }
+}
+
+proc check_symbols { symbols } {
+    set off 0
+
+    # check S_OBJNAME record
+
+    set data [string range $symbols $off [expr $off + 1]]
+    incr off 2
+    binary scan $data s sym_len
+
+    set sym [string range $symbols $off [expr $off + $sym_len - 1]]
+    incr off $sym_len
+
+    check_objname $sym
+
+    # check S_COMPILE3 record
+
+    set data [string range $symbols $off [expr $off + 1]]
+    incr off 2
+    binary scan $data s sym_len
+
+    set sym [string range $symbols $off [expr $off + $sym_len - 1]]
+    incr off $sym_len
+
+    check_compile3 $sym
+}
+
+gas_run codeview1.s "-gcodeview -I $srcdir/$subdir -o tmpdir/codeview1.o" ">&dump.out"
+
+if { [file size "dump.out"] != 0 } {
+    fail "Failed to assemble codeview1.s"
+    return
+} else {
+    pass "Assembled codeview1.s"
+}
+
+gas_host_run "$OBJCOPY --dump-section .debug\\\$S=tmpdir/codeview-debug tmpdir/codeview1.o" ">&dump.out"
+
+if { [file size "dump.out"] != 0 } {
+    fail "Failed to extract .debug\$S section from codeview1.o"
+    return
+} else {
+    pass "Extracted .debug\$S section from codeview1.o"
+}
+
+set fi [open tmpdir/codeview-debug]
+fconfigure $fi -translation binary
+
+# check signature
+
+set data [read $fi 4]
+binary scan $data i cv_sig
+
+if { $cv_sig != 4 } {
+    fail "Invalid CodeView signature"
+    close $fi
+    return
+} else {
+    pass "Correct CodeView signature"
+}
+
+# read string table (DEBUG_S_STRINGTABLE)
+
+set result [read_subsection $fi]
+
+if { [lindex $result 0] != 0xf3 } {
+    fail "Subsection was not string table"
+    close $fi
+    return
+} else {
+    pass "Read string table"
+}
+
+set string_table [lindex $result 1]
+
+# read file checksums (DEBUG_S_FILECHKSMS)
+
+set result [read_subsection $fi]
+
+if { [lindex $result 0] != 0xf4 } {
+    fail "Subsection was not file checksums"
+    close $fi
+    return
+} else {
+    pass "Read file checksums"
+}
+
+check_file_checksums [lindex $result 1] $string_table
+
+# read line info (DEBUG_S_LINES)
+
+set result [read_subsection $fi]
+
+if { [lindex $result 0] != 0xf2 } {
+    fail "Subsection was not line info"
+    close $fi
+    return
+} else {
+    pass "Read line info"
+}
+
+check_lines [lindex $result 1]
+
+# read CodeView symbols (DEBUG_S_SYMBOLS)
+
+set result [read_subsection $fi]
+
+if { [lindex $result 0] != 0xf1 } {
+    fail "Subsection was not symbols"
+    close $fi
+    return
+} else {
+    pass "Read symbols"
+}
+
+check_symbols [lindex $result 1]
+
+close $fi
diff --git a/gas/testsuite/gas/i386/codeview1.s b/gas/testsuite/gas/i386/codeview1.s
new file mode 100644
index 00000000000..9a1018ad1cc
--- /dev/null
+++ b/gas/testsuite/gas/i386/codeview1.s
@@ -0,0 +1,7 @@
+.text
+
+.global main
+main:
+	int3
+	.include "codeview2.s"
+	int3
diff --git a/gas/testsuite/gas/i386/codeview2.s b/gas/testsuite/gas/i386/codeview2.s
new file mode 100644
index 00000000000..f7947fa480e
--- /dev/null
+++ b/gas/testsuite/gas/i386/codeview2.s
@@ -0,0 +1,2 @@
+int3
+int3
-- 
2.37.4

Re: [PATCH] gas: Add --gcodeview option

[Nick Clifton]

Hi Mark,

> This patch adds a --gcodeview option to as, which causes it to emit a
> .debug$S section with line number details in Microsoft's CodeView
> format. My upcoming PDB patches to ld will parse these so they can be
> read by windbg etc.

I encountered one new assembler testsuite failure whilst testing this
patch locally:

   FAIL: Failed to extract .debug$S section from codeview1.o

The lines before it showed a confusing error message:

   Executing on host: sh -c {objcopy --dump-section .debug\$S=tmpdir/codeview-debug tmpdir/codeview1.o 2>&1}  /dev/null dump.out (timeout = 300)
spawn [open ...]

   objcopy: tmpdir/codeview1.o: can't dump section '.debug$S' - it does not exist: file format not recognized

This was using a toolchain configured as --target=x86_64-w64-mingw32

Could you look into this please ?

Cheers
   Nick

Re: [PATCH] gas: Add --gcodeview option

[Mark Harmstone]

On 21/11/22 14:53, Nick Clifton wrote:
> Hi Mark,
>
>> This patch adds a --gcodeview option to as, which causes it to emit a
>> .debug$S section with line number details in Microsoft's CodeView
>> format. My upcoming PDB patches to ld will parse these so they can be
>> read by windbg etc.
>
> I encountered one new assembler testsuite failure whilst testing this
> patch locally:
>
>   FAIL: Failed to extract .debug$S section from codeview1.o
>
> The lines before it showed a confusing error message:
>
>   Executing on host: sh -c {objcopy --dump-section .debug\$S=tmpdir/codeview-debug tmpdir/codeview1.o 2>&1} /dev/null dump.out (timeout = 300)
> spawn [open ...]
>
>   objcopy: tmpdir/codeview1.o: can't dump section '.debug$S' - it does not exist: file format not recognized
>
> This was using a toolchain configured as --target=x86_64-w64-mingw32
>
> Could you look into this please ?
>
> Cheers
>   Nick
>
Hi Nick,

I don't understand this, it's working for me. This is with a target of x86_64-w64-mingw32, and the patch applied to commit 31c1130f35e0ef800ea4d92224a72872ffe4a5db.

Does your tmpdir/codeview1.o actually have a .debug$S section? I'm wondering if maybe something is choking on the dollar sign.

My versions, if it helps...

Expect version  5.45.4
Tcl version     8.6
GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu)

Thanks

Mark

Re: [PATCH] gas: Add --gcodeview option

[Nick Clifton]

Hi Mark,

>>   FAIL: Failed to extract .debug$S section from codeview1.o

> I don't understand this, it's working for me.  

A snafu.  My test build was mis-configured, so it was building ELF binaries
instead of PE binaries (but still pretending to be a -mingw32 toolchain).

*sigh*

With that corrected the tests work.

Patch approved - please apply.  Sorry for the noise.

Cheers
   Nick