gas: Add --gcodeview option

11 files changed, 1018 insertions, 4 deletions

diff --git a/gas/Makefile.am b/gas/Makefile.am
index 4661a718..dc59312 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 \
@@ -106,6 +107,7 @@ 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 1e01f34..1b4f313 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) \
 	gen-sframe.$(OBJEXT) hash.$(OBJEXT) input-file.$(OBJEXT) \
 	input-scrub.$(OBJEXT) listing.$(OBJEXT) literal.$(OBJEXT) \
@@ -555,6 +555,7 @@ GAS_CFILES = \
 	app.c \
 	as.c \
 	atof-generic.c \
+	codeview.c \
 	compress-debug.c \
 	cond.c \
 	depend.c \
@@ -592,6 +593,7 @@ HFILES = \
 	bignum.h \
 	bit_fix.h \
 	cgen.h \
+	codeview.h \
 	compress-debug.h \
 	dwarf2dbg.h \
 	dw2gencfi.h \
@@ -1294,6 +1296,7 @@ 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 80a2cb9..74ffa71 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"
 
@@ -333,6 +334,10 @@ 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, _("\
@@ -483,6 +488,7 @@ 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,
@@ -545,6 +551,9 @@ 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}
@@ -870,6 +879,12 @@ 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
@@ -1429,6 +1444,8 @@ 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 23542e4..61f259f 100644
--- a/gas/as.h
+++ b/gas/as.h
@@ -387,7 +387,8 @@ 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 0000000..da71456
--- /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 0000000..49272b6
--- /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 e23be66..17971db 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 0000000..68b279e
--- /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 0000000..ed606c1
--- /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 0000000..9a1018a
--- /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 0000000..f7947fa
--- /dev/null
+++ b/gas/testsuite/gas/i386/codeview2.s
@@ -0,0 +1,2 @@
+int3
+int3