tests: Add new varlocs test for dwarf_getlocation* functions.

This tests the new dwarf_getlocations, dwarf_getlocation_attr and
dwarf_getlocation_die functions. But it is also an example of how
to handle location expressions and which libdw functions can be
used to access all information required to interpret each DW_OP.

It might make sense to extend this test/example into a program
that verifies various properties of DWARF expressions.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

14 files changed, 1064 insertions, 3 deletions

diff --git a/tests/ChangeLog b/tests/ChangeLog
index b11f27bd..9ea285f7 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,26 @@
+2013-08-30  Mark Wielaard  <mjw@redhat.com>
+
+	* Makefile.am (check_PROGRAMS): Add varlocs.
+	(TESTS): Add run-varlocs.sh.
+	(EXTRA_DIST): Add run-varlocs.sh, testfile_const_type.c,
+	testfile_const_type.bz2, testfile_implicit_pointer.c,
+	testfile_implicit_pointer.bz2, testfile_parameter_ref.c,
+	testfile_entry_value.c, testfile_entry_value.bz2,
+	testfile_implicit_value.c and testfile_implicit_value.bz2.
+	(varlocs_LDADD): New.
+	* run-varlocs: New test.
+	* testfile_const_type.c: New test source file.
+	* testfile_entry_value.c: Likewise.
+	* testfile_implicit_pointer.c: Likewise.
+	* testfile_implicit_value.c: Likewise.
+	* testfile_parameter_ref.c: Likewise.
+	* testfile_const_type.bz2: New test file.
+	* testfile_entry_value.bz2: Likewise.
+	* testfile_implicit_pointer.bz2: Likewise.
+	* testfile_implicit_value.bz2: Likewise.
+	* testfile_parameter_ref.bz2: Likewise.
+	* varlocs.c: New test source.
+
 2013-08-29  Mark Wielaard  <mjw@redhat.com>
 
 	* run-addrcfi.sh: Add case for EM_ARM.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 251ebc4a..e06d914d 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -52,7 +52,7 @@ check_PROGRAMS = arextract arsymtest newfile saridx scnnames sectiondump \
 		  test-flag-nobits dwarf-getstring rerequest_tag \
 		  alldts md5-sha1-test typeiter low_high_pc \
 		  test-elf_cntl_gelf_getshdr dwflsyms dwfllines \
-		  dwfl-report-elf-align
+		  dwfl-report-elf-align varlocs
 asm_TESTS = asm-tst1 asm-tst2 asm-tst3 asm-tst4 asm-tst5 \
 	    asm-tst6 asm-tst7 asm-tst8 asm-tst9
 
@@ -89,7 +89,7 @@ TESTS = run-arextract.sh run-arsymtest.sh newfile test-nlist \
 	run-test-archive64.sh run-readelf-vmcoreinfo.sh \
 	run-readelf-mixed-corenote.sh run-dwfllines.sh \
 	run-dwfl-report-elf-align.sh run-addr2line-test.sh \
-	run-addr2line-i-test.sh
+	run-addr2line-i-test.sh run-varlocs.sh
 
 if !STANDALONE
 check_PROGRAMS += msg_tst md5-sha1-test
@@ -205,7 +205,13 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh \
 	     run-addr2line-i-test.sh testfile-inlines.bz2 \
 	     testfileppc32.bz2 testfileppc64.bz2 \
 	     testfiles390.bz2 testfiles390x.bz2 \
-	     testfilearm.bz2
+	     testfilearm.bz2 \
+	     run-varlocs.sh \
+	     testfile_const_type.c testfile_const_type.bz2 \
+	     testfile_implicit_pointer.c testfile_implicit_pointer.bz2 \
+	     testfile_parameter_ref.c testfile_parameter_ref.bz2 \
+	     testfile_entry_value.c testfile_entry_value.bz2 \
+	     testfile_implicit_value.c testfile_implicit_value.bz2
 
 if USE_VALGRIND
 valgrind_cmd='valgrind -q --trace-children=yes --error-exitcode=1 --run-libc-freeres=no'
@@ -330,6 +336,7 @@ test_elf_cntl_gelf_getshdr_LDADD = $(libelf) $(libmudflap)
 dwflsyms_LDADD = $(libdw) $(libelf) $(libmudflap)
 dwfllines_LDADD = $(libdw) $(libelf) $(libmudflap)
 dwfl_report_elf_align_LDADD = $(libdw) $(libmudflap)
+varlocs_LDADD = $(libdw) $(libelf) $(libmudflap)
 
 if GCOV
 check: check-am coverage
diff --git a/tests/run-varlocs.sh b/tests/run-varlocs.sh
new file mode 100755
index 00000000..9c4b313e
--- /dev/null
+++ b/tests/run-varlocs.sh
@@ -0,0 +1,128 @@
+#! /bin/sh
+# Copyright (C) 2013 Red Hat, Inc.
+# This file is part of elfutils.
+#
+# This file 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.
+#
+# elfutils 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, see <http://www.gnu.org/licenses/>.
+
+. $srcdir/test-subr.sh
+
+# See the source files testfile_const_type.c testfile_implicit_value.c
+# testfile_entry_value.c testfile_parameter_ref.c testfile_implicit_pointer.c
+# how to regenerate the test files (needs GCC 4.8+).
+
+testfiles testfile_const_type testfile_implicit_value testfile_entry_value
+testfiles testfile_parameter_ref testfile_implicit_pointer
+
+testrun_compare ${abs_top_builddir}/tests/varlocs -e testfile_const_type <<\EOF
+module 'testfile_const_type'
+[b] CU 'const_type.c'@0
+  [33] function 'f1'@80483f0
+    frame_base: {call_frame_cfa {bregx(4,4)}}
+    [4b] parameter 'd'
+      [80483f0,804841b) {fbreg(0)}
+    [57] variable 'w'
+      [80483f0,804841b) {fbreg(0), GNU_deref_type(8){long long int,signed,64@[25]}, GNU_const_type{long long int,signed,64@[25]}(8)[0000806745230100], div, GNU_convert{long long unsigned int,unsigned,64@[2c]}, stack_value}
+  [7d] function 'main'@80482f0
+    frame_base: {call_frame_cfa {bregx(4,4)}}
+EOF
+
+testrun_compare ${abs_top_builddir}/tests/varlocs -e testfile_implicit_value <<\EOF
+module 'testfile_implicit_value'
+[b] CU 'implicit_value.c'@0
+  [25] function 'foo'@80483f0
+    frame_base: {call_frame_cfa {bregx(4,4)}}
+    [3e] variable 'a'
+      [80483f0,80483f6) {implicit_value(8){0200000000000000}, piece(8), implicit_value(8){1500000000000000}, piece(8)}
+  [86] function 'main'@80482f0
+    frame_base: {call_frame_cfa {bregx(4,4)}}
+EOF
+
+testrun_compare ${abs_top_builddir}/tests/varlocs -e testfile_entry_value <<\EOF
+module 'testfile_entry_value'
+[b] CU 'entry_value.c'@0
+  [29] function 'foo'@400500
+    frame_base: {call_frame_cfa {bregx(7,8)}}
+    [4a] parameter 'x'
+      [400500,400504) {reg5}
+    [55] parameter 'y'
+      [400500,400504) {reg4}
+  [68] function 'bar'@400510
+    frame_base: {call_frame_cfa {bregx(7,8)}}
+    [89] parameter 'x'
+      [400510,40051c) {reg5}
+      [40051c,40052b) {reg6}
+      [40052b,400531) {GNU_entry_value(1) {reg5}, stack_value}
+    [96] parameter 'y'
+      [400510,40051c) {reg4}
+      [40051c,40052a) {reg3}
+      [40052a,400531) {GNU_entry_value(1) {reg4}, stack_value}
+    [a3] variable 'z'
+      [400524,400528) {reg0}
+      [400528,400529) {reg12}
+      [400529,40052e) {breg0(0), breg12(0), plus, stack_value}
+      [40052e,400531) {reg0}
+  [e9] function 'main'@400400
+    frame_base: {call_frame_cfa {bregx(7,8)}}
+    [10a] parameter 'argc'
+      [400400,400406) {reg5}
+      [400406,40040a) {breg5(-1), stack_value}
+      [40040a,40040b) {GNU_entry_value(1) {reg5}, stack_value}
+    [119] parameter 'argv'
+      [400400,400403) {reg4}
+      [400403,40040b) {GNU_entry_value(1) {reg4}, stack_value}
+EOF
+
+testrun_compare ${abs_top_builddir}/tests/varlocs -e testfile_parameter_ref <<\EOF
+module 'testfile_parameter_ref'
+[b] CU 'parameter_ref.c'@0
+  [77] function 'foo'@400510
+    frame_base: {call_frame_cfa {bregx(7,8)}}
+    [92] parameter 'x'
+      [400510,400523) {reg5}
+    [99] parameter 'y'
+      [400510,400523) {GNU_parameter_ref[42], stack_value}
+    [a5] variable 'a'
+      [400510,400523) {breg5(0), lit1, shl, stack_value}
+    [b0] variable 'b'
+      [400510,400523) {GNU_parameter_ref[42], lit1, shl, stack_value}
+    [be] variable 'c'
+      <constant value>
+    [c4] parameter 'z'
+      <constant value>
+  [cb] function 'main'@400400
+    frame_base: {call_frame_cfa {bregx(7,8)}}
+    [ec] parameter 'x'
+      [400400,400408) {reg5}
+      [400408,400421) {reg3}
+      [400421,400423) {GNU_entry_value(1) {reg5}, stack_value}
+    [f9] parameter 'argv'
+      [400400,400408) {reg4}
+      [400408,400423) {GNU_entry_value(1) {reg4}, stack_value}
+EOF
+
+testrun_compare ${abs_top_builddir}/tests/varlocs -e testfile_implicit_pointer <<\EOF
+module 'testfile_implicit_pointer'
+[b] CU 'implicit_pointer.c'@0
+  [29] function 'foo'@400500
+    frame_base: {call_frame_cfa {bregx(7,8)}}
+    [4a] parameter 'i'
+      [400500,400503) {reg5}
+    [55] variable 'p'
+      [400500,400503) {GNU_implicit_pointer([4a],0) {reg5}}
+  [73] function 'main'@400400
+    frame_base: {call_frame_cfa {bregx(7,8)}}
+EOF
+
+
+exit 0
diff --git a/tests/testfile_const_type.bz2 b/tests/testfile_const_type.bz2
new file mode 100755
index 00000000..fea4a9cb
--- /dev/null
+++ b/tests/testfile_const_type.bz2
diff --git a/tests/testfile_const_type.c b/tests/testfile_const_type.c
new file mode 100644
index 00000000..259007d0
--- /dev/null
+++ b/tests/testfile_const_type.c
@@ -0,0 +1,14 @@
+// gcc -m32 -g -O2 -o const_type const_type.c
+
+__attribute__((noinline, noclone)) int
+f1 (long long d)
+{
+  long long w = d / 0x1234567800000LL;
+  return w;
+}
+
+int
+main ()
+{
+  return f1 (4LL) - f1 (4LL);
+}
diff --git a/tests/testfile_entry_value.bz2 b/tests/testfile_entry_value.bz2
new file mode 100755
index 00000000..fde86c61
--- /dev/null
+++ b/tests/testfile_entry_value.bz2
diff --git a/tests/testfile_entry_value.c b/tests/testfile_entry_value.c
new file mode 100644
index 00000000..d2f232b2
--- /dev/null
+++ b/tests/testfile_entry_value.c
@@ -0,0 +1,19 @@
+// gcc -g -O2 -o entry_value entry_value.c
+int __attribute__((noinline, noclone)) foo (int x, int y)
+{
+  return x + y;
+}
+
+int __attribute__((noinline, noclone)) bar (int x, int y)
+{
+  int z;
+  z = foo (x, y);
+  z += foo (y, x);
+  return z;
+}
+
+int
+main (int argc, char **argv)
+{
+  return bar (argc + 1, argc - 1);
+}
diff --git a/tests/testfile_implicit_pointer.bz2 b/tests/testfile_implicit_pointer.bz2
new file mode 100755
index 00000000..72f6a694
--- /dev/null
+++ b/tests/testfile_implicit_pointer.bz2
diff --git a/tests/testfile_implicit_pointer.c b/tests/testfile_implicit_pointer.c
new file mode 100644
index 00000000..d7e28a0e
--- /dev/null
+++ b/tests/testfile_implicit_pointer.c
@@ -0,0 +1,12 @@
+// gcc -g -O2 -o implicit_pointer implicit_pointer.c
+
+static __attribute__((noinline, noclone)) int foo (int i)
+{
+  int *p = &i;
+  return *p;
+}
+
+int main (void)
+{
+  return foo (23) - 23;
+}
diff --git a/tests/testfile_implicit_value.bz2 b/tests/testfile_implicit_value.bz2
new file mode 100755
index 00000000..c365a99d
--- /dev/null
+++ b/tests/testfile_implicit_value.bz2
diff --git a/tests/testfile_implicit_value.c b/tests/testfile_implicit_value.c
new file mode 100644
index 00000000..8885bbf3
--- /dev/null
+++ b/tests/testfile_implicit_value.c
@@ -0,0 +1,12 @@
+// gcc -m32 -g -O2 -o implicit_value implicit_value.c
+
+static __attribute__((noinline, noclone)) int foo ()
+{
+  unsigned long long a[] = { 2, 21 };
+  return a[0] * a[1];
+}
+
+int main (void)
+{
+  return foo () - 42;
+}
diff --git a/tests/testfile_parameter_ref.bz2 b/tests/testfile_parameter_ref.bz2
new file mode 100755
index 00000000..8ff900de
--- /dev/null
+++ b/tests/testfile_parameter_ref.bz2
diff --git a/tests/testfile_parameter_ref.c b/tests/testfile_parameter_ref.c
new file mode 100644
index 00000000..7fe985f3
--- /dev/null
+++ b/tests/testfile_parameter_ref.c
@@ -0,0 +1,20 @@
+// gcc -g -O2 -o parameter_ref parameter_ref.c
+
+volatile int vv;
+
+/* Don't inline, but do allow clone to create specialized versions.  */
+static __attribute__((noinline)) int
+foo (int x, int y, int z)
+{
+  int a = x * 2;
+  int b = y * 2;
+  int c = z * 2;
+  vv++;
+  return x + z;
+}
+
+int
+main (int x, char **argv)
+{
+  return foo (x, 2, 3) + foo (x, 4, 3) + foo (x + 6, x, 3) + x;
+}
diff --git a/tests/varlocs.c b/tests/varlocs.c
new file mode 100644
index 00000000..6f4d4901
--- /dev/null
+++ b/tests/varlocs.c
@@ -0,0 +1,826 @@
+/* Test program for dwarf location functions.
+   Copyright (C) 2013 Red Hat, Inc.
+   This file is part of elfutils.
+
+   This file 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.
+
+   elfutils 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, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+#include <assert.h>
+#include <argp.h>
+#include <inttypes.h>
+#include <errno.h>
+#include ELFUTILS_HEADER(dw)
+#include ELFUTILS_HEADER(dwfl)
+#include <dwarf.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <error.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "../libdw/known-dwarf.h"
+
+// The Dwarf, Dwarf_CFIs and address bias of
+// cfi table to adjust DWARF addresses against.
+// Needed for DW_OP_call_frame_cfa.
+static Dwarf *dw;
+Dwarf_CFI *cfi_debug;
+Dwarf_CFI *cfi_eh;
+Dwarf_Addr cfi_eh_bias;
+
+// Whether the current function has a DW_AT_frame_base defined.
+// Needed for DW_OP_fbreg.
+bool has_frame_base;
+
+static void
+print_die (Dwarf_Die *die, const char *what, int indent)
+{
+  Dwarf_Addr entrypc;
+  const char *name = dwarf_diename (die) ?: "<unknown>";
+  if (dwarf_entrypc (die, &entrypc) == 0)
+    printf ("%*s[%" PRIx64 "] %s '%s'@%" PRIx64 "\n", indent * 2, "",
+	    dwarf_dieoffset (die), what, name, entrypc);
+  else
+    printf ("%*s[%" PRIx64 "] %s '%s'\n", indent * 2, "",
+	    dwarf_dieoffset (die), what, name);
+}
+
+static const char *
+dwarf_encoding_string (unsigned int code)
+{
+  static const char *const known[] =
+    {
+#define ONE_KNOWN_DW_ATE(NAME, CODE) [CODE] = #NAME,
+      ALL_KNOWN_DW_ATE
+#undef ONE_KNOWN_DW_ATE
+    };
+
+  if (likely (code < sizeof (known) / sizeof (known[0])))
+    return known[code];
+
+  return NULL;
+}
+
+/* BASE must be a base type DIE referenced by a typed DWARF expression op.  */
+static void
+print_base_type (Dwarf_Die *base)
+{
+  assert (dwarf_tag (base) == DW_TAG_base_type);
+
+  Dwarf_Attribute encoding;
+  Dwarf_Word enctype;
+  if (dwarf_attr (base, DW_AT_encoding, &encoding) == NULL
+      || dwarf_formudata (&encoding, &enctype) != 0)
+    error (EXIT_FAILURE, 0, "base type without encoding");
+
+  Dwarf_Attribute bsize;
+  Dwarf_Word bits;
+  if (dwarf_attr (base, DW_AT_byte_size, &bsize) != NULL
+      && dwarf_formudata (&bsize, &bits) == 0)
+    bits *= 8;
+  else if (dwarf_attr (base, DW_AT_bit_size, &bsize) == NULL
+	   || dwarf_formudata (&bsize, &bits) != 0)
+    error (EXIT_FAILURE, 0, "base type without byte or bit size");
+
+  printf ("{%s,%s,%" PRIu64 "@[%" PRIx64 "]}",
+	  dwarf_diename (base),
+	  dwarf_encoding_string (enctype),
+	  bits,
+	  dwarf_dieoffset (base));
+}
+
+static const char *
+dwarf_opcode_string (unsigned int code)
+{
+  static const char *const known[] =
+    {
+#define ONE_KNOWN_DW_OP_DESC(NAME, CODE, DESC) ONE_KNOWN_DW_OP (NAME, CODE)
+#define ONE_KNOWN_DW_OP(NAME, CODE) [CODE] = #NAME,
+      ALL_KNOWN_DW_OP
+#undef ONE_KNOWN_DW_OP
+#undef ONE_KNOWN_DW_OP_DESC
+    };
+
+  if (likely (code < sizeof (known) / sizeof (known[0])))
+    return known[code];
+
+  return NULL;
+}
+
+// Forward reference for print_expr_block.
+static void print_expr (Dwarf_Attribute *, Dwarf_Op *, Dwarf_Addr);
+
+static void
+print_expr_block (Dwarf_Attribute *attr, Dwarf_Op *exprs, int len,
+		  Dwarf_Addr addr)
+{
+  printf ("{");
+  for (int i = 0; i < len; i++)
+    {
+      print_expr (attr, &exprs[i], addr);
+      printf ("%s", (i + 1 < len ? ", " : ""));
+    }
+  printf ("}");
+}
+
+static void
+print_expr_block_addrs (Dwarf_Attribute *attr,
+			Dwarf_Addr begin, Dwarf_Addr end,
+			Dwarf_Op *exprs, int len)
+{
+  printf ("      [%" PRIx64 ",%" PRIx64 ") ", begin, end);
+  print_expr_block (attr, exprs, len, begin);
+  printf ("\n");
+}
+
+static void
+print_expr (Dwarf_Attribute *attr, Dwarf_Op *expr, Dwarf_Addr addr)
+{
+  uint8_t atom = expr->atom;
+  const char *opname = dwarf_opcode_string (atom);
+  assert (opname != NULL);
+
+  switch (atom)
+    {
+    case DW_OP_deref:
+    case DW_OP_dup:
+    case DW_OP_drop:
+    case DW_OP_over:
+    case DW_OP_swap:
+    case DW_OP_rot:
+    case DW_OP_xderef:
+    case DW_OP_abs:
+    case DW_OP_and:
+    case DW_OP_div:
+    case DW_OP_minus:
+    case DW_OP_mod:
+    case DW_OP_mul:
+    case DW_OP_neg:
+    case DW_OP_not:
+    case DW_OP_or:
+    case DW_OP_plus:
+    case DW_OP_shl:
+    case DW_OP_shr:
+    case DW_OP_shra:
+    case DW_OP_xor:
+    case DW_OP_eq:
+    case DW_OP_ge:
+    case DW_OP_gt:
+    case DW_OP_le:
+    case DW_OP_lt:
+    case DW_OP_ne:
+    case DW_OP_lit0 ... DW_OP_lit31:
+    case DW_OP_reg0 ... DW_OP_reg31:
+    case DW_OP_nop:
+    case DW_OP_stack_value:
+      /* No arguments. */
+      printf ("%s", opname);
+      break;
+
+    case DW_OP_form_tls_address:
+      /* No arguments. Special. Pops an address and pushes the
+	 corresponding address in the current thread local
+	 storage. Uses the thread local storage block of the defining
+	 module (executable, shared library). */
+      printf ("%s", opname);
+      break;
+
+    case DW_OP_GNU_push_tls_address:
+      /* No arguments. Special. Not the same as DW_OP_form_tls_address.
+	 Pops an offset into the current thread local strorage and
+	 pushes back the actual address. */
+      printf ("%s", opname);
+      break;
+
+    case DW_OP_call_frame_cfa:
+      /* No arguments. Special. Pushes Call Frame Address as computed
+	 by CFI data (dwarf_cfi_addrframe will fetch that info (either from
+	 the .eh_frame or .debug_frame CFI) and dwarf_frame_cfa translatesr
+         the CFI instructions into a plain DWARF expression.
+	 Never used in CFI itself. */
+
+      if (attr == NULL)
+	error (EXIT_FAILURE, 0, "%s used in CFI", opname);
+
+      printf ("%s ", opname);
+      if (cfi_eh == NULL && cfi_debug == NULL)
+	error (EXIT_FAILURE, 0, "DW_OP_call_frame_cfa used but no cfi found.");
+
+      Dwarf_Frame *frame;
+      if (dwarf_cfi_addrframe (cfi_eh, addr + cfi_eh_bias, &frame) != 0
+	  && dwarf_cfi_addrframe (cfi_debug, addr, &frame) != 0)
+	error (EXIT_FAILURE, 0, "dwarf_cfi_addrframe 0x%" PRIx64 ": %s",
+	       addr, dwarf_errmsg (-1));
+
+      Dwarf_Op *cfa_ops;
+      size_t cfa_nops;
+      if (dwarf_frame_cfa (frame, &cfa_ops, &cfa_nops) != 0)
+	error (EXIT_FAILURE, 0, "dwarf_frame_cfa 0x%" PRIx64 ": %s",
+	       addr, dwarf_errmsg (-1));
+      if (cfa_nops < 1)
+	error (EXIT_FAILURE, 0, "dwarf_frame_cfa no ops");
+      print_expr_block (NULL, cfa_ops, cfa_nops, 0);
+      free (frame);
+      break;
+
+    case DW_OP_push_object_address:
+      /* No arguments. Special. Pushes object address explicitly.
+       Normally only done implicitly by DW_AT_data_member_location.
+       Never used in CFI. */
+      if (attr == NULL)
+	error (EXIT_FAILURE, 0, "%s used in CFI", opname);
+      printf ("%s", opname);
+      break;
+
+    case DW_OP_addr:
+      /* 1 address argument. */
+      printf ("%s(0x%" PRIx64 ")", opname, (Dwarf_Addr) expr->number);
+      break;
+
+    case DW_OP_const1u:
+    case DW_OP_const2u:
+    case DW_OP_const4u:
+    case DW_OP_const8u:
+    case DW_OP_constu:
+    case DW_OP_pick:
+    case DW_OP_plus_uconst:
+    case DW_OP_regx:
+    case DW_OP_piece:
+    case DW_OP_deref_size:
+    case DW_OP_xderef_size:
+      /* 1 numeric unsigned argument. */
+      printf ("%s(%" PRIu64 ")", opname, expr->number);
+      break;
+
+    case DW_OP_call2:
+    case DW_OP_call4:
+    case DW_OP_call_ref:
+      /* 1 DIE offset argument for more ops in location attribute of DIE.
+         Never used in CFI.  */
+      {
+	if (attr == NULL)
+	  error (EXIT_FAILURE, 0, "%s used in CFI", opname);
+
+	Dwarf_Attribute call_attr;
+	if (dwarf_getlocation_attr (attr, expr, &call_attr) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_attr for %s error %s",
+		 opname, dwarf_errmsg (-1));
+
+	Dwarf_Die call_die;
+	if (dwarf_getlocation_die (attr, expr, &call_die) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_die for %s error %s",
+		 opname, dwarf_errmsg (-1));
+
+	Dwarf_Op *call_ops;
+	size_t call_len;
+	if (dwarf_getlocation (&call_attr, &call_ops, &call_len) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation for entry: %s",
+		 dwarf_errmsg (-1));
+
+	printf ("%s([%" PRIx64 "]) ", opname, dwarf_dieoffset (&call_die));
+	print_expr_block (&call_attr, call_ops, call_len, addr);
+      }
+      break;
+
+    case DW_OP_const1s:
+    case DW_OP_const2s:
+    case DW_OP_const4s:
+    case DW_OP_const8s:
+    case DW_OP_consts:
+    case DW_OP_skip:
+    case DW_OP_bra:
+    case DW_OP_breg0 ... DW_OP_breg31:
+      /* 1 numeric signed argument. */
+      printf ("%s(%" PRId64 ")", opname, (Dwarf_Sword) expr->number);
+      break;
+
+    case DW_OP_fbreg:
+      /* 1 numeric signed argument. Offset from frame base. */
+      if (attr == NULL)
+	  error (EXIT_FAILURE, 0, "%s used in CFI", opname);
+
+      if (! has_frame_base)
+	error (EXIT_FAILURE, 0, "DW_OP_fbreg used without a frame base");
+
+      printf ("%s(%" PRId64 ")", opname, (Dwarf_Sword) expr->number);
+      break;
+
+    case DW_OP_bregx:
+      /* 2 arguments, unsigned register number, signed offset. */
+      printf ("%s(%" PRIu64 ",%" PRId64 ")", opname,
+	      expr->number, (Dwarf_Sword) expr->number2);
+      break;
+
+    case DW_OP_bit_piece:
+      /* 2 arguments, unsigned size, unsigned offset. */
+      printf ("%s(%" PRIu64 ",%" PRIu64 ")", opname,
+	      expr->number, expr->number2);
+      break;
+
+    case DW_OP_implicit_value:
+      /* Special, unsigned size plus block. */
+      {
+	Dwarf_Attribute const_attr;
+	Dwarf_Block block;
+	if (dwarf_getlocation_attr (attr, expr, &const_attr) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_attr: %s",
+		 dwarf_errmsg (-1));
+
+	if (dwarf_formblock (&const_attr, &block) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_formblock: %s",
+		 dwarf_errmsg (-1));
+
+	/* This is the "old" way. Check they result in the same.  */
+	Dwarf_Block block_impl;
+	if (dwarf_getlocation_implicit_value (attr, expr, &block_impl) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_implicit_value: %s",
+		 dwarf_errmsg (-1));
+
+	assert (expr->number == block.length);
+	assert (block.length == block_impl.length);
+	printf ("%s(%" PRIu64 "){", opname, block.length);
+	for (size_t i = 0; i < block.length; i++)
+	  {
+	    printf ("%02x", block.data[i]);
+	    assert (block.data[i] == block_impl.data[i]);
+	  }
+	printf("}");
+      }
+      break;
+
+    case DW_OP_GNU_implicit_pointer:
+      /* Special, DIE offset, signed offset. Referenced DIE has a
+	 location or const_value attribute. */
+      {
+	if (attr == NULL)
+	  error (EXIT_FAILURE, 0, "%s used in CFI", opname);
+
+	Dwarf_Attribute attrval;
+	if (dwarf_getlocation_implicit_pointer (attr, expr, &attrval) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_implicit_pointer: %s",
+		 dwarf_errmsg (-1));
+
+	// Sanity check, results should be the same.
+	Dwarf_Attribute attrval2;
+	if (dwarf_getlocation_attr (attr, expr, &attrval2) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_attr: %s",
+		 dwarf_errmsg (-1));
+
+	assert (dwarf_whatattr (&attrval) == dwarf_whatattr (&attrval2));
+	assert (dwarf_whatform (&attrval) == dwarf_whatform (&attrval2));
+	// In theory two different valp pointers could point to the same
+	// value. But here we really expect them to be the equal.
+	assert (attrval.valp == attrval2.valp);
+
+	Dwarf_Die impl_die;
+	if (dwarf_getlocation_die (attr, expr, &impl_die) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_due: %s",
+		 dwarf_errmsg (-1));
+
+	printf ("%s([%" PRIx64 "],%" PRId64 ") ", opname,
+		dwarf_dieoffset (&impl_die), expr->number2);
+
+	if (dwarf_whatattr (&attrval) == DW_AT_const_value)
+	  printf ("<constant value>"); // Lookup type...
+	else
+	  {
+	    // Lookup the location description at the current address.
+	    Dwarf_Op *exprval;
+	    size_t exprval_len;
+	    int locs = dwarf_getlocation_addr (&attrval, addr,
+					       &exprval, &exprval_len, 1);
+	    if (locs == 0)
+	      printf ("<no location>"); // XXX should that be flagged?
+	    else if (locs == 1)
+	      print_expr_block (&attrval, exprval, exprval_len, addr);
+	    else
+	      error (EXIT_FAILURE, 0,
+		     "dwarf_getlocation_addr attrval at addr 0x%" PRIx64
+		     ", locs (%d): %s", addr, locs, dwarf_errmsg (-1));
+	  }
+      }
+      break;
+
+    case DW_OP_GNU_entry_value:
+      /* Special, unsigned size plus expression block. All registers
+	 inside the block should be interpreted as they had on
+	 entering the function. dwarf_getlocation_attr will return an
+	 attribute containing the block as locexpr which can be
+	 retrieved with dwarf_getlocation.  */
+      {
+	Dwarf_Attribute entry_attr;
+	if (dwarf_getlocation_attr (attr, expr, &entry_attr) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_attr: %s",
+		 dwarf_errmsg (-1));
+
+	Dwarf_Op *entry_ops;
+	size_t entry_len;
+	if (dwarf_getlocation (&entry_attr, &entry_ops, &entry_len) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation for entry: %s",
+		 dwarf_errmsg (-1));
+
+	printf ("%s(%zd) ", opname, entry_len);
+	print_expr_block (attr, entry_ops, entry_len, addr);
+      }
+      break;
+
+    case DW_OP_GNU_parameter_ref:
+      /* Special, unsigned CU relative DIE offset pointing to a
+	 DW_TAG_formal_parameter. The value that parameter had at the
+	 call site of the current function will be put on the DWARF
+	 stack. The value can be retrieved by finding the
+	 DW_TAG_GNU_call_site_parameter which has as
+	 DW_AT_abstract_origin the same formal parameter DIE. */
+      {
+	Dwarf_Die param;
+	if (dwarf_getlocation_die (attr, expr, &param) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_die: %s",
+		 dwarf_errmsg (-1));
+	// XXX actually lookup DW_TAG_GNU_call_site_parameter
+	printf ("%s[%" PRIx64 "]", opname, dwarf_dieoffset (&param));
+	assert (expr->number == dwarf_cuoffset (&param));
+	assert (dwarf_tag (&param) == DW_TAG_formal_parameter);
+      }
+      break;
+
+    case DW_OP_GNU_convert:
+    case DW_OP_GNU_reinterpret:
+      /* Special, unsigned CU relative DIE offset pointing to a
+	 DW_TAG_base_type. Pops a value, converts or reinterprets the
+	 value to the given type. When the argument is zero the value
+	 becomes untyped again. */
+      {
+	Dwarf_Die type;
+	Dwarf_Off off = expr->number;
+	if (off != 0)
+	  {
+	    if (dwarf_getlocation_die (attr, expr, &type) != 0)
+	      error (EXIT_FAILURE, 0, "dwarf_getlocation_die: %s",
+		     dwarf_errmsg (-1));
+	    off = dwarf_dieoffset (&type);
+	    assert (expr->number == dwarf_cuoffset (&type));
+	    printf ("%s", opname);
+	    print_base_type (&type);
+	  }
+	else
+	  printf ("%s[%" PRIu64 "]", opname, off);
+
+      }
+      break;
+
+    case DW_OP_GNU_regval_type:
+      /* Special, unsigned register number plus unsigned CU relative
+         DIE offset pointing to a DW_TAG_base_type. */
+      {
+	Dwarf_Die type;
+	if (dwarf_getlocation_die (attr, expr, &type) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_die: %s",
+		 dwarf_errmsg (-1));
+	assert (expr->number2 == dwarf_cuoffset (&type));
+	// XXX check size against base_type size?
+	printf ("%s(reg%" PRIu64 ")", opname, expr->number);
+	print_base_type (&type);
+      }
+      break;
+
+    case DW_OP_GNU_deref_type:
+      /* Special, unsigned size plus unsigned CU relative DIE offset
+	 pointing to a DW_TAG_base_type. */ 
+      {
+	Dwarf_Die type;
+	if (dwarf_getlocation_die (attr, expr, &type) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_die: %s",
+		 dwarf_errmsg (-1));
+	assert (expr->number2 == dwarf_cuoffset (&type));
+	// XXX check size against base_type size?
+	printf ("%s(%" PRIu64 ")", opname, expr->number);
+	print_base_type (&type);
+      }
+      break;
+
+    case DW_OP_GNU_const_type:
+      /* Special, unsigned CU relative DIE offset pointing to a
+	 DW_TAG_base_type, an unsigned size length plus a block with
+	 the constant value. */
+      {
+	Dwarf_Die type;
+	if (dwarf_getlocation_die (attr, expr, &type) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_die: %s",
+		 dwarf_errmsg (-1));
+	assert (expr->number == dwarf_cuoffset (&type));
+
+	Dwarf_Attribute const_attr;
+	if (dwarf_getlocation_attr (attr, expr, &const_attr) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_getlocation_attr for type: %s",
+		 dwarf_errmsg (-1));
+	  
+	Dwarf_Block block;
+	if (dwarf_formblock (&const_attr, &block) != 0)
+	  error (EXIT_FAILURE, 0, "dwarf_formblock for type: %s",
+		 dwarf_errmsg (-1));
+
+	printf ("%s", opname);
+	print_base_type (&type);
+	printf ("(%" PRIu64 ")[", block.length);
+	for (size_t i = 0; i < block.length; i++)
+	  printf ("%02x", block.data[i]);
+	printf("]");
+      }
+      break;
+
+    default:
+      error (EXIT_FAILURE, 0, "unhandled opcode: DW_OP_%s (0x%x)",
+	     opname, atom);
+    }
+}
+
+/* Get all variables and print their value expressions. */
+static void
+print_varlocs (Dwarf_Die *funcdie)
+{
+  // Display frame base for function if it exists.
+  // Should be used for DW_OP_fbreg.
+  has_frame_base = dwarf_hasattr (funcdie, DW_AT_frame_base);
+  if (has_frame_base)
+    {
+      Dwarf_Attribute fb_attr;
+      if (dwarf_attr (funcdie, DW_AT_frame_base, &fb_attr) == NULL)
+	error (EXIT_FAILURE, 0, "dwarf_attr fb: %s", dwarf_errmsg (-1));
+
+      Dwarf_Op *fb_expr;
+      size_t fb_exprlen;
+      if (dwarf_getlocation (&fb_attr, &fb_expr, &fb_exprlen) == 0)
+	{
+	  // Covers all of function.
+	  Dwarf_Addr entrypc;
+	  if (dwarf_entrypc (funcdie, &entrypc) != 0)
+	    error (EXIT_FAILURE, 0, "dwarf_entrypc: %s", dwarf_errmsg (-1));
+
+	  printf ("    frame_base: ");
+	  if (entrypc == 0)
+	    printf ("XXX zero address"); // XXX bad DWARF?
+	  else
+	    print_expr_block (&fb_attr, fb_expr, fb_exprlen, entrypc);
+	  printf ("\n");
+	}
+      else
+	{
+	  Dwarf_Addr base, start, end;
+	  ptrdiff_t off = 0;
+	  printf ("    frame_base:\n");
+          while ((off = dwarf_getlocations (&fb_attr, off, &base,
+					    &start, &end,
+					    &fb_expr, &fb_exprlen)) > 0)
+	    {
+	      printf ("      (%" PRIx64 ",%" PRIx64 ") ", start, end);
+	      print_expr_block (&fb_attr, fb_expr, fb_exprlen, start);
+	      printf ("\n");
+	    }
+
+	  if (off < 0)
+	    error (EXIT_FAILURE, 0, "dwarf_getlocations fb: %s",
+		   dwarf_errmsg (-1));
+	}
+    }
+  else if (dwarf_tag (funcdie) == DW_TAG_inlined_subroutine)
+    {
+      // See whether the subprogram we are inlined into has a frame
+      // base we should use.
+      Dwarf_Die *scopes;
+      int n = dwarf_getscopes_die (funcdie, &scopes);
+      if (n <= 0)
+	error (EXIT_FAILURE, 0, "dwarf_getscopes_die: %s", dwarf_errmsg (-1));
+
+      while (n-- > 0)
+	if (dwarf_tag (&scopes[n]) == DW_TAG_subprogram
+	    && dwarf_hasattr (&scopes[n], DW_AT_frame_base))
+	  {
+	    has_frame_base = true;
+	    break;
+	  }
+      free (scopes);
+    }
+
+  if (! dwarf_haschildren (funcdie))
+    return;
+
+  Dwarf_Die child;
+  int res = dwarf_child (funcdie, &child);
+  if (res < 0)
+    error (EXIT_FAILURE, 0, "dwarf_child: %s", dwarf_errmsg (-1));
+
+  /* We thought there was a child, but the child list was actually
+     empty. This isn't technically an error in the DWARF, but it is
+     certainly non-optimimal.  */
+  if (res == 1)
+    return;
+
+  do
+    {
+      int tag = dwarf_tag (&child);
+      if (tag == DW_TAG_variable || tag == DW_TAG_formal_parameter)
+	{
+	  const char *what = tag == DW_TAG_variable ? "variable" : "parameter";
+	  print_die (&child, what, 2);
+
+	  if (dwarf_hasattr (&child, DW_AT_location))
+	    {
+	      Dwarf_Attribute attr;
+	      if (dwarf_attr (&child, DW_AT_location, &attr) == NULL)
+		error (EXIT_FAILURE, 0, "dwarf_attr: %s", dwarf_errmsg (-1));
+
+	      Dwarf_Op *expr;
+	      size_t exprlen;
+	      if (dwarf_getlocation (&attr, &expr, &exprlen) == 0)
+		{
+		  // Covers all ranges of the function.
+		  // Evaluate the expression block for each range.
+		  ptrdiff_t offset = 0;
+		  Dwarf_Addr base, begin, end;
+		  do
+		    {
+		      offset = dwarf_ranges (funcdie, offset, &base,
+					     &begin, &end);
+		      if (offset < 0)
+			error (EXIT_FAILURE, 0, "dwarf_ranges: %s",
+			       dwarf_errmsg (-1));
+
+		      if (offset > 0)
+			{
+			  if (exprlen == 0)
+			    printf ("      (%"
+				    PRIx64 ",%" PRIx64
+				    ") <empty expression>\n", begin, end);
+			  else
+			    print_expr_block_addrs (&attr, begin, end,
+						    expr, exprlen);
+			}
+		    }
+		  while (offset > 0);
+
+		  if (offset < 0)
+		    error (EXIT_FAILURE, 0, "dwarf_ranges: %s",
+			   dwarf_errmsg (-1));
+		}
+	      else
+		{
+		  Dwarf_Addr base, begin, end;
+		  ptrdiff_t offset = 0;
+		  while ((offset = dwarf_getlocations (&attr, offset,
+						       &base, &begin, &end,
+						       &expr, &exprlen)) > 0)
+		    if (begin >= end)
+		      printf ("      (%" PRIx64 ",%" PRIx64
+			      ") <empty range>\n", begin, end); // XXX report?
+		    else
+		      {
+			print_expr_block_addrs (&attr, begin, end,
+						expr, exprlen);
+
+			// Extra sanity check for dwarf_getlocation_addr
+			// Must at least find one range for begin and end-1.
+			Dwarf_Op *expraddr;
+			size_t expraddr_len;
+			int locs = dwarf_getlocation_addr (&attr, begin,
+							   &expraddr,
+							   &expraddr_len, 1);
+			assert (locs == 1);
+			locs = dwarf_getlocation_addr (&attr, end - 1,
+						       &expraddr,
+						       &expraddr_len, 1);
+			assert (locs == 1);
+		      }
+
+		  if (offset < 0)
+		    error (EXIT_FAILURE, 0, "dwarf_getlocations: %s",
+			   dwarf_errmsg (-1));
+		}
+	    }
+	  else if (dwarf_hasattr (&child, DW_AT_const_value))
+	    {
+	      printf ("      <constant value>\n"); // Lookup type and print.
+	    }
+	  else
+	    {
+	      printf ("      <no value>\n");
+	    }
+	}
+    }
+  while (dwarf_siblingof (&child, &child) == 0);
+}
+
+static int
+handle_instance (Dwarf_Die *funcdie, void *arg __attribute__ ((unused)))
+{
+  print_die (funcdie, "inlined function", 1);
+  print_varlocs (funcdie);
+
+  return DWARF_CB_OK;
+}
+
+static int
+handle_function (Dwarf_Die *funcdie, void *arg __attribute__((unused)))
+{
+  if (dwarf_func_inline (funcdie) > 0)
+    {
+      // abstract inline definition, find all inlined instances.
+
+      // Note this is convenient for listing all instances together
+      // so you can easily compare the location expressions describing
+      // the variables and parameters, but it isn't very efficient
+      // since it will walk the DIE tree multiple times.
+      if (dwarf_func_inline_instances (funcdie, &handle_instance, NULL) != 0)
+	error (EXIT_FAILURE, 0, "dwarf_func_inline_instances: %s",
+	       dwarf_errmsg (-1));
+    }
+  else
+    {
+      // Contains actual code, not just a declaration?
+      Dwarf_Addr entrypc;
+      if (dwarf_entrypc (funcdie, &entrypc) == 0)
+	{
+	  print_die (funcdie, "function", 1);
+	  print_varlocs (funcdie);
+	}
+    }
+
+  return DWARF_CB_OK;
+}
+
+int
+main (int argc, char *argv[])
+{
+  int remaining;
+  Dwfl *dwfl;
+  (void) argp_parse (dwfl_standard_argp (), argc, argv, 0, &remaining,
+                     &dwfl);
+  assert (dwfl != NULL);
+
+  Dwarf_Die *cu = NULL;
+  Dwarf_Addr dwbias;
+  while ((cu = dwfl_nextcu (dwfl, cu, &dwbias)) != NULL)
+    {
+      /* Only walk actual compile units (not partial units) that
+	 contain code.  */
+      Dwarf_Addr cubase;
+      if (dwarf_tag (cu) == DW_TAG_compile_unit
+	  && dwarf_lowpc (cu, &cubase) == 0)
+	{
+	  Dwfl_Module *mod = dwfl_cumodule (cu);
+	  Dwarf_Addr modbias;
+	  dw = dwfl_module_getdwarf (mod, &modbias);
+	  assert (dwbias == modbias);
+
+	  const char *mainfile;
+	  const char *modname = dwfl_module_info (mod, NULL,
+						  NULL, NULL,
+						  NULL, NULL,
+						  &mainfile,
+						  NULL);
+	  if (modname == NULL)
+	    error (EXIT_FAILURE, 0, "dwfl_module_info: %s", dwarf_errmsg (-1));
+
+	  const char *name = (modname[0] != '\0'
+			      ? modname
+			      :  basename (mainfile));
+	  printf ("module '%s'\n", name);
+	  print_die (cu, "CU", 0);
+
+	  Dwarf_Addr elfbias;
+	  Elf *elf = dwfl_module_getelf (mod, &elfbias);
+
+	  // CFI. We need both since sometimes neither is complete.
+	  cfi_debug = dwarf_getcfi (dw); // No bias needed, same file.
+	  cfi_eh = dwarf_getcfi_elf (elf);
+	  cfi_eh_bias = dwbias - elfbias;
+
+	  // Get the actual CU DIE and walk all functions inside it.
+	  Dwarf_Die cudie;
+	  uint8_t offsize;
+	  uint8_t addrsize;
+	  if (dwarf_diecu (cu, &cudie, &addrsize, &offsize) == NULL)
+	    error (EXIT_FAILURE, 0, "dwarf_diecu %s", dwarf_errmsg (-1));
+
+	  if (dwarf_getfuncs (cu, handle_function, NULL, 0) != 0)
+	    error (EXIT_FAILURE, 0, "dwarf_getfuncs %s",
+		   dwarf_errmsg (-1));
+	}
+    }
+
+  dwfl_end (dwfl);
+  return 0;
+}