diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index d9e0885..8ce2405 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1254,6 +1254,7 @@ OBJS = \
 	cfgloopanal.o \
 	cfgloopmanip.o \
 	cfgrtl.o \
+	ctfout.o \
 	symtab.o \
 	cgraph.o \
 	cgraphbuild.o \
@@ -2532,6 +2533,8 @@ GTFILES = $(CPPLIB_H) $(srcdir)/input.h $(srcdir)/coretypes.h \
   $(srcdir)/dwarf2asm.c \
   $(srcdir)/dwarf2cfi.c \
   $(srcdir)/dwarf2out.c \
+  $(srcdir)/ctfout.h \
+  $(srcdir)/ctfout.c \
   $(srcdir)/tree-vect-generic.c \
   $(srcdir)/dojump.c $(srcdir)/emit-rtl.h \
   $(srcdir)/emit-rtl.c $(srcdir)/except.h $(srcdir)/explow.c $(srcdir)/expr.c \
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index f4d6688..9cf6252 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -205,6 +205,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "lto-section-names.h"
 #include "stringpool.h"
 #include "attribs.h"
+#include "ctfout.h"
 
 /* Queue of cgraph nodes scheduled to be added into cgraph.  This is a
    secondary queue used during optimization to accommodate passes that
@@ -2844,17 +2845,22 @@ symbol_table::finalize_compilation_unit (void)
 
   if (!seen_error ())
     {
-      /* Emit early debug for reachable functions, and by consequence,
-	 locally scoped symbols.  */
+      /* Emit early debug and CTF debug info for reachable functions, and by
+	 consequence, locally scoped symbols.  */
       struct cgraph_node *cnode;
       FOR_EACH_FUNCTION_WITH_GIMPLE_BODY (cnode)
-	(*debug_hooks->early_global_decl) (cnode->decl);
+	{
+	  (*debug_hooks->early_global_decl) (cnode->decl);
+	  ctf_early_global_decl (cnode->decl);
+	}
 
       /* Clean up anything that needs cleaning up after initial debug
 	 generation.  */
       debuginfo_early_start ();
       (*debug_hooks->early_finish) (main_input_filename);
+      ctf_early_finish (main_input_filename);
       debuginfo_early_stop ();
+
     }
 
   /* Finally drive the pass manager.  */
diff --git a/gcc/ctfout.c b/gcc/ctfout.c
new file mode 100644
index 0000000..1ce9829
--- /dev/null
+++ b/gcc/ctfout.c
@@ -0,0 +1,175 @@
+/* Output CTF format from GCC.
+   Copyright (C) 2019 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/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "target.h"
+#include "rtl.h"
+#include "tree.h"
+#include "memmodel.h"
+#include "tm_p.h"
+#include "varasm.h"
+#include "output.h"
+#include "dwarf2asm.h"
+#include "debug.h"
+#include "ctfout.h"
+
+/* A CTF container object - one per translation unit.  */
+
+static GTY (()) ctf_container_ref tu_ctfc;
+
+static int ctf_label_num;
+
+/* Pointers to various CTF sections.  */
+
+static GTY (()) section * ctf_info_section;
+
+/* Section names used to hold CTF debugging information.  */
+
+#ifndef CTF_INFO_SECTION_NAME
+#define CTF_INFO_SECTION_NAME  ".ctf"
+#endif
+
+/* Section flags for .ctf section.  */
+
+/* CTF debug info section.  */
+
+#define CTF_INFO_SECTION_FLAGS (SECTION_DEBUG)
+
+/* Maximum size (in bytes) of an artificially generated CTF label.  */
+
+#define MAX_CTF_LABEL_BYTES 40
+
+static char ctf_info_section_label[MAX_CTF_LABEL_BYTES];
+
+#ifndef CTF_INFO_SECTION_LABEL
+#define CTF_INFO_SECTION_LABEL			"Lctf"
+#endif
+
+/* CTF container setup and teardown routines.  */
+
+/* Allocate a new CTF container with the desired flags.  */
+
+static inline ctf_container_ref
+new_ctf_container (unsigned char ctp_flags)
+{
+  tu_ctfc = ggc_cleared_alloc<ctf_container_t> ();
+
+  tu_ctfc->ctfc_magic = CTF_MAGIC;
+  tu_ctfc->ctfc_version = CTF_VERSION;
+  tu_ctfc->ctfc_flags = ctp_flags;
+
+  return tu_ctfc;
+}
+
+/* Initialize a CTF container per translation unit.  */
+
+static void
+init_ctf_containers (void)
+{
+  tu_ctfc = new_ctf_container (0);
+}
+
+/* Delete the CTF container's resources.  */
+
+static void
+delete_ctf_container (ctf_container_ref ctfc)
+{
+  /* FIXME - CTF container can be cleaned up now.
+     Will the ggc machinery take care of cleaning up the container structure
+     including the hash_map members etc. ?  */
+  if (ctfc)
+    {
+      ctfc = NULL;
+    }
+}
+
+/* Initialize the various sections and labels for CTF output.  */
+
+void
+init_ctf_sections (void)
+{
+  ctf_info_section = get_section (CTF_INFO_SECTION_NAME,
+				  CTF_INFO_SECTION_FLAGS,
+				  NULL);
+  ASM_GENERATE_INTERNAL_LABEL (ctf_info_section_label,
+			       CTF_INFO_SECTION_LABEL, ctf_label_num++);
+}
+
+/* Asm'out the CTF preamble.  */
+
+static void
+ctf_asm_preamble (ctf_container_ref ctfc)
+{
+  dw2_asm_output_data (2, ctfc->ctfc_magic,
+		       "CTF preamble magic number");
+  dw2_asm_output_data (1, ctfc->ctfc_version, "CTF preamble version");
+  dw2_asm_output_data (1, ctfc->ctfc_flags, "CTF preamble flags");
+}
+
+/* Output the CTF header.  */
+
+static void
+output_ctf_header (ctf_container_ref ctfc)
+{
+  switch_to_section (ctf_info_section);
+  ASM_OUTPUT_LABEL (asm_out_file, ctf_info_section_label);
+
+  ctf_asm_preamble (ctfc);
+}
+
+/* CTF routines interfacing to the compiler.  */
+
+void
+ctf_debug_init (void)
+{
+  init_ctf_containers ();
+}
+
+void
+ctf_early_finish (const char * ARG_UNUSED (filename))
+{
+  if (ctf_debug_info_level == CTFINFO_LEVEL_NONE)
+    return;
+
+  init_ctf_sections ();
+
+  output_ctf_header (tu_ctfc);
+}
+
+void
+ctf_early_global_decl (tree ARG_UNUSED (decl))
+{
+  /* Generate CTF type information if appropriate debug level is set
+     (ctf_debug_info_level == CTFINFO_LEVEL_NORMAL).  */
+}
+
+/* Reset all state within ctfout.c so that we can rerun the compiler
+   within the same process.  For use by toplev::finalize.  */
+
+void
+ctfout_c_finalize (void)
+{
+  ctf_info_section = NULL;
+
+  delete_ctf_container (tu_ctfc);
+}
+
+#include "gt-ctfout.h"
diff --git a/gcc/ctfout.h b/gcc/ctfout.h
new file mode 100644
index 0000000..f281aaf
--- /dev/null
+++ b/gcc/ctfout.h
@@ -0,0 +1,53 @@
+/* ctfout.h - Various declarations for functions found in ctfout.c
+   Copyright (C) 2019 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/>.  */
+
+/* This file defines all data structures used by the compiler to generate
+   CTF types.  These are compiler internal representations and closely
+   reflect the CTF format requirements in <ctf.h>.  */
+
+#ifndef GCC_CTFOUT_H
+#define GCC_CTFOUT_H 1
+
+#include "ctf.h"
+
+/* CTF container structure.
+   It is the context passed around when generating CTF debug info.  There is
+   one container per translation unit.  */
+
+typedef struct GTY (()) ctf_container
+{
+  /* CTF Preamble.  */
+  unsigned short ctfc_magic;
+  unsigned char ctfc_version;
+  unsigned char ctfc_flags;
+  /* CTF Types.  */
+  // hash_map <ctf_dtdef_hash, ctf_dtdefp_t> * GTY (()) ctfc_types;
+} ctf_container_t;
+
+typedef ctf_container_t * ctf_container_ref;
+
+void ctf_debug_init (void);
+
+void ctf_early_global_decl (tree decl);
+
+void ctf_early_finish (const char * filename);
+
+void ctfout_c_finalize (void);
+
+#endif /* GCC_CTFOUT_H */
diff --git a/gcc/gengtype.c b/gcc/gengtype.c
index 5331733..39de737 100644
--- a/gcc/gengtype.c
+++ b/gcc/gengtype.c
@@ -1724,8 +1724,8 @@ open_base_files (void)
       "tree-dfa.h", "tree-ssa.h", "reload.h", "cpplib.h", "tree-chrec.h",
       "except.h", "output.h",  "cfgloop.h", "target.h", "lto-streamer.h",
       "target-globals.h", "ipa-ref.h", "cgraph.h", "symbol-summary.h",
-      "ipa-prop.h", "ipa-fnsummary.h", "dwarf2out.h", "omp-general.h",
-      "omp-offload.h", NULL
+      "ipa-prop.h", "ipa-fnsummary.h", "dwarf2out.h", "ctfout.h",
+      "omp-general.h", "omp-offload.h", NULL
     };
     const char *const *ifp;
     outf_p gtype_desc_c;
diff --git a/gcc/passes.c b/gcc/passes.c
index c6331cb..c0f1e57 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -63,6 +63,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "diagnostic-core.h" /* for fnotice */
 #include "stringpool.h"
 #include "attribs.h"
+#include "ctfout.h"
 
 using namespace gcc;
 
@@ -322,7 +323,11 @@ rest_of_decl_compilation (tree decl,
       /* Avoid confusing the debug information machinery when there are
 	 errors.  */
       && !seen_error ())
-    (*debug_hooks->early_global_decl) (decl);
+	{
+	  (*debug_hooks->early_global_decl) (decl);
+	  /* Generate CTF debug info.  */
+	  ctf_early_global_decl (decl);
+	}
 }
 
 /* Called after finishing a record, union or enumeral type.  */
diff --git a/gcc/testsuite/gcc.dg/debug/ctf/ctf-1.c b/gcc/testsuite/gcc.dg/debug/ctf/ctf-1.c
new file mode 100644
index 0000000..1be0dfb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/ctf/ctf-1.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-gt" } */
+
+void func(void)
+{
+}
diff --git a/gcc/testsuite/gcc.dg/debug/ctf/ctf-preamble-1.c b/gcc/testsuite/gcc.dg/debug/ctf/ctf-preamble-1.c
new file mode 100644
index 0000000..476ca80
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/ctf/ctf-preamble-1.c
@@ -0,0 +1,11 @@
+/* Verify the CTF preamble in the CTF section.  */
+
+/* { dg-do compile )  */
+/* { dg-options "-O0 -gt -dA" } */
+/* { dg-final { scan-assembler "0xdff2.*CTF preamble magic number" } } */
+/* { dg-final { scan-assembler "0x4.*CTF preamble version" } } */
+/* { dg-final { scan-assembler "0.*CTF preamble flags" } } */
+
+void func (void)
+{
+}
diff --git a/gcc/testsuite/gcc.dg/debug/ctf/ctf.exp b/gcc/testsuite/gcc.dg/debug/ctf/ctf.exp
new file mode 100644
index 0000000..46055f8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/ctf/ctf.exp
@@ -0,0 +1,41 @@
+#   Copyright (C) 2002-2019 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
+
+# Disable on ptx (in sync with DWARF testsuite)
+if { [istarget nvptx-*-*] } {
+    return
+}
+
+# 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.
+dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.\[cS\] ]] \
+	"" $DEFAULT_CFLAGS
+
+# All done.
+dg-finish
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2-ctf-1.c b/gcc/testsuite/gcc.dg/debug/dwarf2-ctf-1.c
new file mode 100644
index 0000000..4ffa8ee
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2-ctf-1.c
@@ -0,0 +1,7 @@
+/* Verify that CTF debug info can co-exist with other debug formats.  */
+/* { dg-do compile } */
+/* { dg-options "-gt -dA" } */
+/* { dg-final { scan-assembler "0xdff2.*CTF preamble magic number" } } */
+
+void func (void)
+{ }
diff --git a/gcc/toplev.c b/gcc/toplev.c
index 116be7b..d150dfc 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -72,6 +72,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "pass_manager.h"
 #include "auto-profile.h"
 #include "dwarf2out.h"
+#include "ctfout.h"
 #include "ipa-reference.h"
 #include "symbol-summary.h"
 #include "tree-vrp.h"
@@ -1312,6 +1313,8 @@ parse_alignment_opts (void)
 static void
 process_options (void)
 {
+  const char *language_string = lang_hooks.name;
+
   /* Just in case lang_hooks.post_options ends up calling a debug_hook.
      This can happen with incorrect pre-processed input. */
   debug_hooks = &do_nothing_debug_hooks;
@@ -1484,6 +1487,17 @@ process_options (void)
 	debug_info_level = DINFO_LEVEL_NONE;
     }
 
+  /* CTF is supported for only C at this time.
+     Compiling with -flto results in frontend language of GNU GIMPLE.  */
+  if (!lang_GNU_C () && !lang_GNU_GIMPLE ()
+      && ctf_debug_info_level > CTFINFO_LEVEL_NONE)
+    {
+      warning_at (UNKNOWN_LOCATION, 0,
+		  "CTF debug info requested, but not supported for %s frontend",
+		  language_string);
+      ctf_debug_info_level = CTFINFO_LEVEL_NONE;
+    }
+
   if (flag_dump_final_insns && !flag_syntax_only && !no_backend)
     {
       FILE *final_output = fopen (flag_dump_final_insns, "w");
@@ -1556,6 +1570,9 @@ process_options (void)
       flag_var_tracking_uninit = 0;
     }
 
+  if (ctf_debug_info_level > CTFINFO_LEVEL_NONE)
+    ctf_debug_init ();
+
   /* The debug hooks are used to implement -fdump-go-spec because it
      gives a simple and stable API for all the information we need to
      dump.  */
@@ -2391,6 +2408,7 @@ toplev::finalize (void)
   cgraph_c_finalize ();
   cgraphunit_c_finalize ();
   dwarf2out_c_finalize ();
+  ctfout_c_finalize ();
   gcse_c_finalize ();
   ipa_cp_c_finalize ();
   ira_costs_c_finalize ();
diff --git a/include/ctf.h b/include/ctf.h
new file mode 100644
index 0000000..3a6f266
--- /dev/null
+++ b/include/ctf.h
@@ -0,0 +1,483 @@
+/* CTF format description.
+   Copyright (C) 2019 Free Software Foundation, Inc.
+
+   This file is part of libctf.
+
+   libctf 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.
+
+   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; see the file COPYING.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef	_CTF_H
+#define	_CTF_H
+
+#include <sys/types.h>
+#include <limits.h>
+#include <stdint.h>
+
+
+#ifdef	__cplusplus
+extern "C"
+{
+#endif
+
+/* CTF - Compact ANSI-C Type Format
+
+   This file format can be used to compactly represent the information needed
+   by a debugger to interpret the ANSI-C types used by a given program.
+   Traditionally, this kind of information is generated by the compiler when
+   invoked with the -g flag and is stored in "stabs" strings or in the more
+   modern DWARF format.  CTF provides a representation of only the information
+   that is relevant to debugging a complex, optimized C program such as the
+   operating system kernel in a form that is significantly more compact than
+   the equivalent stabs or DWARF representation.  The format is data-model
+   independent, so consumers do not need different code depending on whether
+   they are 32-bit or 64-bit programs; libctf automatically compensates for
+   endianness variations.  CTF assumes that a standard ELF symbol table is
+   available for use in the debugger, and uses the structure and data of the
+   symbol table to avoid storing redundant information.  The CTF data may be
+   compressed on disk or in memory, indicated by a bit in the header.  CTF may
+   be interpreted in a raw disk file, or it may be stored in an ELF section,
+   typically named .ctf.  Data structures are aligned so that a raw CTF file or
+   CTF ELF section may be manipulated using mmap(2).
+
+   The CTF file or section itself has the following structure:
+
+   +--------+--------+---------+----------+----------+-------+--------+
+   |  file  |  type  |  data   | function | variable | data  | string |
+   | header | labels | objects |   info   |   info   | types | table  |
+   +--------+--------+---------+----------+----------+-------+--------+
+
+   The file header stores a magic number and version information, encoding
+   flags, and the byte offset of each of the sections relative to the end of the
+   header itself.  If the CTF data has been uniquified against another set of
+   CTF data, a reference to that data also appears in the the header.  This
+   reference is the name of the label corresponding to the types uniquified
+   against.
+
+   Following the header is a list of labels, used to group the types included in
+   the data types section.  Each label is accompanied by a type ID i.  A given
+   label refers to the group of types whose IDs are in the range [0, i].
+
+   Data object and function records are stored in the same order as they appear
+   in the corresponding symbol table, except that symbols marked SHN_UNDEF are
+   not stored and symbols that have no type data are padded out with zeroes.
+   For each data object, the type ID (a small integer) is recorded.  For each
+   function, the type ID of the return type and argument types is recorded.
+
+   Variable records (as distinct from data objects) provide a modicum of support
+   for non-ELF systems, mapping a variable name to a CTF type ID.  The variable
+   names are sorted into ASCIIbetical order, permitting binary searching.
+
+   The data types section is a list of variable size records that represent each
+   type, in order by their ID.  The types themselves form a directed graph,
+   where each node may contain one or more outgoing edges to other type nodes,
+   denoted by their ID.
+
+   Strings are recorded as a string table ID (0 or 1) and a byte offset into the
+   string table.  String table 0 is the internal CTF string table.  String table
+   1 is the external string table, which is the string table associated with the
+   ELF symbol table for this object.  CTF does not record any strings that are
+   already in the symbol table, and the CTF string table does not contain any
+   duplicated strings.
+
+   If the CTF data has been merged with another parent CTF object, some outgoing
+   edges may refer to type nodes that exist in another CTF object.  The debugger
+   and libctf library are responsible for connecting the appropriate objects
+   together so that the full set of types can be explored and manipulated.
+
+   This connection is done purely using the ctf_import() function.  There is no
+   notation anywhere in the child CTF file indicating which parent it is
+   connected to: it is the debugger's responsibility to track this.  */
+
+#define CTF_MAX_TYPE	0xfffffffe	/* Max type identifier value.  */
+#define CTF_MAX_PTYPE	0x7fffffff	/* Max parent type identifier value.  */
+#define CTF_MAX_NAME 0x7fffffff		/* Max offset into a string table.  */
+#define CTF_MAX_VLEN	0xffffff /* Max struct, union, enum members or args.  */
+
+/* See ctf_type_t */
+#define CTF_MAX_SIZE	0xfffffffe	/* Max size of a v2 type in bytes. */
+#define CTF_LSIZE_SENT	0xffffffff	/* Sentinel for v2 ctt_size.  */
+
+  /* Start of actual data structure definitions.
+
+     Every field in these structures must have corresponding code in the
+     endianness-swapping machinery in libctf/ctf-open.c.  */
+
+typedef struct ctf_preamble
+{
+  unsigned short ctp_magic;	/* Magic number (CTF_MAGIC).  */
+  unsigned char ctp_version;	/* Data format version number (CTF_VERSION).  */
+  unsigned char ctp_flags;	/* Flags (see below).  */
+} ctf_preamble_t;
+
+typedef struct ctf_header
+{
+  ctf_preamble_t cth_preamble;
+  uint32_t cth_parlabel;	/* Ref to name of parent lbl uniq'd against.  */
+  uint32_t cth_parname;		/* Ref to basename of parent.  */
+  uint32_t cth_lbloff;		/* Offset of label section.  */
+  uint32_t cth_objtoff;		/* Offset of object section.  */
+  uint32_t cth_funcoff;		/* Offset of function section.  */
+  uint32_t cth_varoff;		/* Offset of variable section.  */
+  uint32_t cth_typeoff;		/* Offset of type section.  */
+  uint32_t cth_stroff;		/* Offset of string section.  */
+  uint32_t cth_strlen;		/* Length of string section in bytes.  */
+} ctf_header_t;
+
+#define cth_magic   cth_preamble.ctp_magic
+#define cth_version cth_preamble.ctp_version
+#define cth_flags   cth_preamble.ctp_flags
+
+#define CTF_MAGIC	0xdff2	/* Magic number identifying header.  */
+
+/* Data format version number.  */
+
+/* v1 upgraded to v2 is not quite the same as native v2 (the boundary between
+   parent and child types is different), and you can write it out again via
+   ctf_compress_write(), so we must track whether the thing was originally v1 or
+   not.  If we were writing the header from scratch, we would add a *pair* of
+   version number fields to allow for this, but this will do for now.  (A flag
+   will not do, because we need to encode both the version we came from and the
+   version we went to, not just "we were upgraded".) */
+
+# define CTF_VERSION_1 1
+# define CTF_VERSION_1_UPGRADED_3 2
+# define CTF_VERSION_2 3
+
+#define CTF_VERSION_3 4
+#define CTF_VERSION CTF_VERSION_3 /* Current version.  */
+
+#define CTF_F_COMPRESS	0x1	/* Data buffer is compressed by libctf.  */
+
+typedef struct ctf_lblent
+{
+  uint32_t ctl_label;		/* Ref to name of label.  */
+  uint32_t ctl_type;		/* Last type associated with this label.  */
+} ctf_lblent_t;
+
+typedef struct ctf_varent
+{
+  uint32_t ctv_name;		/* Reference to name in string table.  */
+  uint32_t ctv_type;		/* Index of type of this variable.  */
+} ctf_varent_t;
+
+/* In format v2, type sizes, measured in bytes, come in two flavours.  Nearly
+   all of them fit into a (UINT_MAX - 1), and thus can be stored in the ctt_size
+   member of a ctf_stype_t.  The maximum value for these sizes is CTF_MAX_SIZE.
+   Types larger than this must be stored in the ctf_lsize member of a
+   ctf_type_t.  Use of this member is indicated by the presence of
+   CTF_LSIZE_SENT in ctt_size.  */
+
+typedef struct ctf_stype
+{
+  uint32_t ctt_name;		/* Reference to name in string table.  */
+  uint32_t ctt_info;		/* Encoded kind, variant length (see below).  */
+#ifndef __GNUC__
+  union
+  {
+    uint32_t _size;		/* Size of entire type in bytes.  */
+    uint32_t _type;		/* Reference to another type.  */
+  } _u;
+#else
+  __extension__
+  union
+  {
+    uint32_t ctt_size;		/* Size of entire type in bytes.  */
+    uint32_t ctt_type;		/* Reference to another type.  */
+  };
+#endif
+} ctf_stype_t;
+
+typedef struct ctf_type
+{
+  uint32_t ctt_name;		/* Reference to name in string table.  */
+  uint32_t ctt_info;		/* Encoded kind, variant length (see below).  */
+#ifndef __GNUC__
+union
+  {
+    uint32_t _size;		/* Always CTF_LSIZE_SENT.  */
+    uint32_t _type;		/* Do not use.  */
+  } _u;
+#else
+  __extension__
+  union
+  {
+    uint32_t ctt_size;		/* Always CTF_LSIZE_SENT.  */
+    uint32_t ctt_type;		/* Do not use.  */
+  };
+#endif
+  uint32_t ctt_lsizehi;		/* High 32 bits of type size in bytes.  */
+  uint32_t ctt_lsizelo;		/* Low 32 bits of type size in bytes.  */
+} ctf_type_t;
+
+#ifndef __GNUC__
+#define ctt_size _u._size	/* For fundamental types that have a size.  */
+#define ctt_type _u._type	/* For types that reference another type.  */
+#endif
+
+/* The following macros and inline functions compose and decompose values for
+   ctt_info and ctt_name, as well as other structures that contain name
+   references.  Use outside libdtrace-ctf itself is explicitly for access to CTF
+   files directly: types returned from the library will always appear to be
+   CTF_V2.
+
+   v1: (transparently upgraded to v2 at open time: may be compiled out of the
+   library)
+               ------------------------
+   ctt_info:   | kind | isroot | vlen |
+               ------------------------
+               15   11    10    9     0
+
+   v2:
+               ------------------------
+   ctt_info:   | kind | isroot | vlen |
+               ------------------------
+               31    26    25  24     0
+
+   CTF_V1 and V2 _INFO_VLEN have the same interface:
+
+   kind = CTF_*_INFO_KIND(c.ctt_info);     <-- CTF_K_* value (see below)
+   vlen = CTF_*_INFO_VLEN(fp, c.ctt_info); <-- length of variable data list
+
+   stid = CTF_NAME_STID(c.ctt_name);     <-- string table id number (0 or 1)
+   offset = CTF_NAME_OFFSET(c.ctt_name); <-- string table byte offset
+
+   c.ctt_info = CTF_TYPE_INFO(kind, vlen);
+   c.ctt_name = CTF_TYPE_NAME(stid, offset);  */
+
+# define CTF_V1_INFO_KIND(info)		(((info) & 0xf800) >> 11)
+# define CTF_V1_INFO_ISROOT(info)	(((info) & 0x0400) >> 10)
+# define CTF_V1_INFO_VLEN(info)		(((info) & CTF_MAX_VLEN_V1))
+
+#define CTF_V2_INFO_KIND(info)		(((info) & 0xfc000000) >> 26)
+#define CTF_V2_INFO_ISROOT(info)	(((info) & 0x2000000) >> 25)
+#define CTF_V2_INFO_VLEN(info)		(((info) & CTF_MAX_VLEN))
+
+#define CTF_NAME_STID(name)		((name) >> 31)
+#define CTF_NAME_OFFSET(name)		((name) & CTF_MAX_NAME)
+
+/* V2 only. */
+#define CTF_TYPE_INFO(kind, isroot, vlen) \
+	(((kind) << 26) | (((isroot) ? 1 : 0) << 25) | ((vlen) & CTF_MAX_VLEN))
+
+#define CTF_TYPE_NAME(stid, offset) \
+	(((stid) << 31) | ((offset) & CTF_MAX_NAME))
+
+/* The next set of macros are for public consumption only.  Not used internally,
+   since the relevant type boundary is dependent upon the version of the file at
+   *opening* time, not the version after transparent upgrade.  Use
+   ctf_type_isparent() / ctf_type_ischild() for that.  */
+
+#define CTF_V2_TYPE_ISPARENT(fp, id)	((id) <= CTF_MAX_PTYPE)
+#define CTF_V2_TYPE_ISCHILD(fp, id)	((id) > CTF_MAX_PTYPE)
+#define CTF_V2_TYPE_TO_INDEX(id)	((id) & CTF_MAX_PTYPE)
+#define CTF_V2_INDEX_TO_TYPE(id, child) ((child) ? ((id) | (CTF_MAX_PTYPE+1)) : (id))
+
+# define CTF_V1_TYPE_ISPARENT(fp, id)	((id) <= CTF_MAX_PTYPE_V1)
+# define CTF_V1_TYPE_ISCHILD(fp, id)	((id) > CTF_MAX_PTYPE_V1)
+# define CTF_V1_TYPE_TO_INDEX(id)	((id) & CTF_MAX_PTYPE_V1)
+# define CTF_V1_INDEX_TO_TYPE(id, child) ((child) ? ((id) | (CTF_MAX_PTYPE_V1+1)) : (id))
+
+/* Valid for both V1 and V2. */
+#define CTF_TYPE_LSIZE(cttp) \
+	(((uint64_t)(cttp)->ctt_lsizehi) << 32 | (cttp)->ctt_lsizelo)
+#define CTF_SIZE_TO_LSIZE_HI(size)	((uint32_t)((uint64_t)(size) >> 32))
+#define CTF_SIZE_TO_LSIZE_LO(size)	((uint32_t)(size))
+
+#define CTF_STRTAB_0	0	/* String table id 0 (in-CTF).  */
+#define CTF_STRTAB_1	1	/* String table id 1 (ELF strtab).  */
+
+/* Values for CTF_TYPE_KIND().  If the kind has an associated data list,
+   CTF_INFO_VLEN() will extract the number of elements in the list, and
+   the type of each element is shown in the comments below. */
+
+#define CTF_K_UNKNOWN	0	/* Unknown type (used for padding).  */
+#define CTF_K_INTEGER	1	/* Variant data is CTF_INT_DATA (see below).  */
+#define CTF_K_FLOAT	2	/* Variant data is CTF_FP_DATA (see below).  */
+#define CTF_K_POINTER	3	/* ctt_type is referenced type.  */
+#define CTF_K_ARRAY	4	/* Variant data is single ctf_array_t.  */
+#define CTF_K_FUNCTION	5	/* ctt_type is return type, variant data is
+				   list of argument types (unsigned short's for v1,
+				   uint32_t's for v2).  */
+#define CTF_K_STRUCT	6	/* Variant data is list of ctf_member_t's.  */
+#define CTF_K_UNION	7	/* Variant data is list of ctf_member_t's.  */
+#define CTF_K_ENUM	8	/* Variant data is list of ctf_enum_t's.  */
+#define CTF_K_FORWARD	9	/* No additional data; ctt_name is tag.  */
+#define CTF_K_TYPEDEF	10	/* ctt_type is referenced type.  */
+#define CTF_K_VOLATILE	11	/* ctt_type is base type.  */
+#define CTF_K_CONST	12	/* ctt_type is base type.  */
+#define CTF_K_RESTRICT	13	/* ctt_type is base type.  */
+#define CTF_K_SLICE	14	/* Variant data is a ctf_slice_t.  */
+
+#define CTF_K_MAX	63	/* Maximum possible (V2) CTF_K_* value.  */
+
+/* Values for ctt_type when kind is CTF_K_INTEGER.  The flags, offset in bits,
+   and size in bits are encoded as a single word using the following macros.
+   (However, you can also encode the offset and bitness in a slice.)  */
+
+#define CTF_INT_ENCODING(data) (((data) & 0xff000000) >> 24)
+#define CTF_INT_OFFSET(data)   (((data) & 0x00ff0000) >> 16)
+#define CTF_INT_BITS(data)     (((data) & 0x0000ffff))
+
+#define CTF_INT_DATA(encoding, offset, bits) \
+       (((encoding) << 24) | ((offset) << 16) | (bits))
+
+#define CTF_INT_SIGNED	0x01	/* Integer is signed (otherwise unsigned).  */
+#define CTF_INT_CHAR	0x02	/* Character display format.  */
+#define CTF_INT_BOOL	0x04	/* Boolean display format.  */
+#define CTF_INT_VARARGS	0x08	/* Varargs display format.  */
+
+/* Use CTF_CHAR to produce a char that agrees with the system's native
+   char signedness.  */
+#if CHAR_MIN == 0
+# define CTF_CHAR (CTF_INT_CHAR)
+#else
+# define CTF_CHAR (CTF_INT_CHAR | CTF_INT_SIGNED)
+#endif
+
+/* Values for ctt_type when kind is CTF_K_FLOAT.  The encoding, offset in bits,
+   and size in bits are encoded as a single word using the following macros.
+   (However, you can also encode the offset and bitness in a slice.)  */
+
+#define CTF_FP_ENCODING(data)  (((data) & 0xff000000) >> 24)
+#define CTF_FP_OFFSET(data)    (((data) & 0x00ff0000) >> 16)
+#define CTF_FP_BITS(data)      (((data) & 0x0000ffff))
+
+#define CTF_FP_DATA(encoding, offset, bits) \
+       (((encoding) << 24) | ((offset) << 16) | (bits))
+
+/* Variant data when kind is CTF_K_FLOAT is an encoding in the top eight bits.  */
+#define CTF_FP_ENCODING(data)	(((data) & 0xff000000) >> 24)
+
+#define CTF_FP_SINGLE	1	/* IEEE 32-bit float encoding.  */
+#define CTF_FP_DOUBLE	2	/* IEEE 64-bit float encoding.  */
+#define CTF_FP_CPLX	3	/* Complex encoding.  */
+#define CTF_FP_DCPLX	4	/* Double complex encoding.  */
+#define CTF_FP_LDCPLX	5	/* Long double complex encoding.  */
+#define CTF_FP_LDOUBLE	6	/* Long double encoding.  */
+#define CTF_FP_INTRVL	7	/* Interval (2x32-bit) encoding.  */
+#define CTF_FP_DINTRVL	8	/* Double interval (2x64-bit) encoding.  */
+#define CTF_FP_LDINTRVL	9	/* Long double interval (2x128-bit) encoding.  */
+#define CTF_FP_IMAGRY	10	/* Imaginary (32-bit) encoding.  */
+#define CTF_FP_DIMAGRY	11	/* Long imaginary (64-bit) encoding.  */
+#define CTF_FP_LDIMAGRY	12	/* Long double imaginary (128-bit) encoding.  */
+
+#define CTF_FP_MAX	12	/* Maximum possible CTF_FP_* value */
+
+/* A slice increases the offset and reduces the bitness of the referenced
+   ctt_type, which must be a type which has an encoding (fp, int, or enum).  We
+   also store the referenced type in here, because it is easier to keep the
+   ctt_size correct for the slice than to shuffle the size into here and keep
+   the ctt_type where it is for other types.  */
+
+typedef struct ctf_slice
+{
+  uint32_t cts_type;
+  unsigned char cts_offset;
+  unsigned char cts_bits;
+} ctf_slice_t;
+
+typedef struct ctf_array
+{
+  uint32_t cta_contents;	/* Reference to type of array contents.  */
+  uint32_t cta_index;		/* Reference to type of array index.  */
+  uint32_t cta_nelems;		/* Number of elements.  */
+} ctf_array_t;
+
+/* Most structure members have bit offsets that can be expressed using a short.
+   Some don't.  ctf_member_t is used for structs which cannot contain any of
+   these large offsets, whereas ctf_lmember_t is used in the latter case.  If
+   any member of a given struct has an offset that cannot be expressed using a
+   uint32_t, all members will be stored as type ctf_lmember_t.  This is expected
+   to be very rare (but nonetheless possible).  */
+
+#define CTF_LSTRUCT_THRESH	536870912
+
+typedef struct ctf_member_v2
+{
+  uint32_t ctm_name;		/* Reference to name in string table.  */
+  uint32_t ctm_offset;		/* Offset of this member in bits.  */
+  uint32_t ctm_type;		/* Reference to type of member.  */
+} ctf_member_t;
+
+typedef struct ctf_lmember_v2
+{
+  uint32_t ctlm_name;		/* Reference to name in string table.  */
+  uint32_t ctlm_offsethi;	/* High 32 bits of member offset in bits.  */
+  uint32_t ctlm_type;		/* Reference to type of member.  */
+  uint32_t ctlm_offsetlo;	/* Low 32 bits of member offset in bits.  */
+} ctf_lmember_t;
+
+#define	CTF_LMEM_OFFSET(ctlmp) \
+	(((uint64_t)(ctlmp)->ctlm_offsethi) << 32 | (ctlmp)->ctlm_offsetlo)
+#define	CTF_OFFSET_TO_LMEMHI(offset)	((uint32_t)((uint64_t)(offset) >> 32))
+#define	CTF_OFFSET_TO_LMEMLO(offset)	((uint32_t)(offset))
+
+typedef struct ctf_enum
+{
+  uint32_t cte_name;		/* Reference to name in string table.  */
+  int32_t cte_value;		/* Value associated with this name.  */
+} ctf_enum_t;
+
+/* The ctf_archive is a collection of ctf_file_t's stored together. The format
+   is suitable for mmap()ing: this control structure merely describes the
+   mmap()ed archive (and overlaps the first few bytes of it), hence the
+   greater care taken with integral types.  All CTF files in an archive
+   must have the same data model.  (This is not validated.)
+
+   All integers in this structure are stored in little-endian byte order.
+
+   The code relies on the fact that everything in this header is a uint64_t
+   and thus the header needs no padding (in particular, that no padding is
+   needed between ctfa_ctfs and the unnamed ctfa_archive_modent array
+   that follows it).
+
+   This is *not* the same as the data structure returned by the ctf_arc_*()
+   functions:  this is the low-level on-disk representation.  */
+
+#define CTFA_MAGIC 0x8b47f2a4d7623eeb	/* Random.  */
+struct ctf_archive
+{
+  /* Magic number.  (In loaded files, overwritten with the file size
+     so ctf_arc_close() knows how much to munmap()).  */
+  uint64_t ctfa_magic;
+
+  /* CTF data model.  */
+  uint64_t ctfa_model;
+
+  /* Number of CTF files in the archive.  */
+  uint64_t ctfa_nfiles;
+
+  /* Offset of the name table.  */
+  uint64_t ctfa_names;
+
+  /* Offset of the CTF table.  Each element starts with a size (a uint64_t
+     in network byte order) then a ctf_file_t of that size.  */
+  uint64_t ctfa_ctfs;
+};
+
+/* An array of ctfa_nnamed of this structure lies at
+   ctf_archive[ctf_archive->ctfa_modents] and gives the ctfa_ctfs or
+   ctfa_names-relative offsets of each name or ctf_file_t.  */
+
+typedef struct ctf_archive_modent
+{
+  uint64_t name_offset;
+  uint64_t ctf_offset;
+} ctf_archive_modent_t;
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif				/* _CTF_H */
