Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/tests/varlocs.c b/tests/varlocs.c
new file mode 100644
index 0000000..0e43229
--- /dev/null
+++ b/tests/varlocs.c
@@ -0,0 +1,1074 @@
+/* Test program for dwarf location functions.
+ Copyright (C) 2013, 2015 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_Addr cfi_debug_bias;
+Dwarf_CFI *cfi_eh;
+Dwarf_Addr cfi_eh_bias;
+
+bool is_ET_REL;
+
+// 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 DWARF_ONE_KNOWN_DW_ATE(NAME, CODE) [CODE] = #NAME,
+ DWARF_ALL_KNOWN_DW_ATE
+#undef DWARF_ONE_KNOWN_DW_ATE
+ };
+
+ if (likely (code < sizeof (known) / sizeof (known[0])))
+ return known[code];
+
+ return NULL;
+}
+
+static const char *
+dwarf_tag_string (unsigned int tag)
+{
+ switch (tag)
+ {
+#define DWARF_ONE_KNOWN_DW_TAG(NAME, CODE) case CODE: return #NAME;
+ DWARF_ALL_KNOWN_DW_TAG
+#undef DWARF_ONE_KNOWN_DW_TAG
+ default:
+ return NULL;
+ }
+}
+
+static const char *
+dwarf_attr_string (unsigned int attrnum)
+{
+ switch (attrnum)
+ {
+#define DWARF_ONE_KNOWN_DW_AT(NAME, CODE) case CODE: return #NAME;
+ DWARF_ALL_KNOWN_DW_AT
+#undef DWARF_ONE_KNOWN_DW_AT
+ default:
+ return NULL;
+ }
+}
+
+static const char *
+dwarf_form_string (unsigned int form)
+{
+ switch (form)
+ {
+#define DWARF_ONE_KNOWN_DW_FORM(NAME, CODE) case CODE: return #NAME;
+ DWARF_ALL_KNOWN_DW_FORM
+#undef DWARF_ONE_KNOWN_DW_FORM
+ default:
+ 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 = 0;
+ 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 DWARF_ONE_KNOWN_DW_OP(NAME, CODE) [CODE] = #NAME,
+ DWARF_ALL_KNOWN_DW_OP
+#undef DWARF_ONE_KNOWN_DW_OP
+ };
+
+ 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 + cfi_debug_bias,
+ &frame) == 0)
+ {
+ 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);
+ }
+ else if (is_ET_REL)
+ {
+ /* XXX In ET_REL files there might be an .eh_frame with relocations
+ we don't handle (e.g. X86_64_PC32). Maybe we should? */
+ printf ("{...}\n");
+ }
+ else
+ error (EXIT_FAILURE, 0, "dwarf_cfi_addrframe 0x%" PRIx64 ": %s",
+ addr, dwarf_errmsg (-1));
+ 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_die: %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>"); // This means "optimized out".
+ 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_variable_value:
+ /* Special, DIE 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_attr (attr, expr, &attrval) != 0)
+ error (EXIT_FAILURE, 0, "dwarf_getlocation_attr: %s",
+ dwarf_errmsg (-1));
+
+ Dwarf_Die impl_die;
+ if (dwarf_getlocation_die (attr, expr, &impl_die) != 0)
+ error (EXIT_FAILURE, 0, "dwarf_getlocation_die: %s",
+ dwarf_errmsg (-1));
+
+ printf ("%s([%" PRIx64 "]) ", opname, dwarf_dieoffset (&impl_die));
+
+ 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>"); // This means "optimized out".
+ 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, ¶m) != 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 (¶m));
+ assert (expr->number == dwarf_cuoffset (¶m));
+ assert (dwarf_tag (¶m) == 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;
+}
+
+struct attr_arg
+{
+ int depth;
+ Dwarf_Addr entrypc;
+};
+
+static int
+handle_attr (Dwarf_Attribute *attr, void *arg)
+{
+ int depth = ((struct attr_arg *) arg)->depth;
+ Dwarf_Addr entrypc = ((struct attr_arg *) arg)->entrypc;
+
+ unsigned int code = dwarf_whatattr (attr);
+ unsigned int form = dwarf_whatform (attr);
+
+ printf ("%*s%s (%s)", depth * 2, "",
+ dwarf_attr_string (code), dwarf_form_string (form));
+
+ /* If we can get an DWARF expression (or location lists) from this
+ attribute we'll print it, otherwise we'll ignore it. But if
+ there is an error while the attribute has the "correct" form then
+ we'll report an error (we can only really check DW_FORM_exprloc
+ other forms can be ambiguous). */
+ Dwarf_Op *expr;
+ size_t exprlen;
+ bool printed = false;
+ int res = dwarf_getlocation (attr, &expr, &exprlen);
+ if (res == 0)
+ {
+ printf (" ");
+ print_expr_block (attr, expr, exprlen, entrypc);
+ printf ("\n");
+ printed = true;
+ }
+ else if (form == DW_FORM_exprloc)
+ {
+ error (0, 0, "%s dwarf_getlocation failed: %s",
+ dwarf_attr_string (code), dwarf_errmsg (-1));
+ return DWARF_CB_ABORT;
+ }
+ else
+ {
+ Dwarf_Addr base, begin, end;
+ ptrdiff_t offset = 0;
+ while ((offset = dwarf_getlocations (attr, offset,
+ &base, &begin, &end,
+ &expr, &exprlen)) > 0)
+ {
+ if (! printed)
+ printf ("\n");
+ printf ("%*s", depth * 2, "");
+ print_expr_block_addrs (attr, begin, end, expr, exprlen);
+ printed = true;
+ }
+ }
+
+ if (! printed)
+ printf ("\n");
+
+ return DWARF_CB_OK;
+}
+
+static void
+handle_die (Dwarf_Die *die, int depth, bool outer_has_frame_base,
+ Dwarf_Addr outer_entrypc)
+{
+ /* CU DIE already printed. */
+ if (depth > 0)
+ {
+ const char *name = dwarf_diename (die);
+ if (name != NULL)
+ printf ("%*s[%" PRIx64 "] %s \"%s\"\n", depth * 2, "",
+ dwarf_dieoffset (die), dwarf_tag_string (dwarf_tag (die)),
+ name);
+ else
+ printf ("%*s[%" PRIx64 "] %s\n", depth * 2, "",
+ dwarf_dieoffset (die), dwarf_tag_string (dwarf_tag (die)));
+ }
+
+ struct attr_arg arg;
+ arg.depth = depth + 1;
+
+ /* The (lowest) address to use for (looking up) operands that depend
+ on address. */
+ Dwarf_Addr die_entrypc;
+ if (dwarf_entrypc (die, &die_entrypc) != 0 || die_entrypc == 0)
+ {
+ /* Try to get the lowest address of the first range covered. */
+ Dwarf_Addr base, start, end;
+ if (dwarf_ranges (die, 0, &base, &start, &end) <= 0 || start == 0)
+ die_entrypc = outer_entrypc;
+ else
+ die_entrypc = start;
+ }
+ arg.entrypc = die_entrypc;
+
+ /* Whether this or the any outer DIE has a frame base. Used as
+ sanity check when printing experssions that use DW_OP_fbreg. */
+ bool die_has_frame_base = dwarf_hasattr (die, DW_AT_frame_base);
+ die_has_frame_base |= outer_has_frame_base;
+ has_frame_base = die_has_frame_base;
+
+ /* Look through all attributes to find those that contain DWARF
+ expressions and print those. We expect to handle all attributes,
+ anything else is an error. */
+ if (dwarf_getattrs (die, handle_attr, &arg, 0) != 1)
+ error (EXIT_FAILURE, 0, "Couldn't get all attributes: %s",
+ dwarf_errmsg (-1));
+
+ /* Handle children and siblings recursively depth first. */
+ Dwarf_Die child;
+ if (dwarf_haschildren (die) != 0 && dwarf_child (die, &child) == 0)
+ handle_die (&child, depth + 1, die_has_frame_base, die_entrypc);
+
+ Dwarf_Die sibling;
+ if (dwarf_siblingof (die, &sibling) == 0)
+ handle_die (&sibling, depth, outer_has_frame_base, outer_entrypc);
+}
+
+int
+main (int argc, char *argv[])
+{
+ /* With --exprlocs we process all DIEs looking for any attribute
+ which contains an DWARF expression (but not location lists) and
+ print those. Otherwise we process all function DIEs and print
+ all DWARF expressions and location lists associated with
+ parameters and variables). */
+ bool exprlocs = false;
+ if (argc > 1 && strcmp ("--exprlocs", argv[1]) == 0)
+ {
+ exprlocs = true;
+ argv[1] = "";
+ }
+
+ 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;
+ bool found_cu = false;
+ while ((cu = dwfl_nextcu (dwfl, cu, &dwbias)) != NULL)
+ {
+ /* Only walk actual compile units (not partial units) that
+ contain code if we are only interested in the function variable
+ locations. */
+ Dwarf_Addr cubase;
+ if (dwarf_tag (cu) == DW_TAG_compile_unit
+ && (exprlocs || dwarf_lowpc (cu, &cubase) == 0))
+ {
+ found_cu = true;
+
+ 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 = dwfl_module_dwarf_cfi (mod, &cfi_debug_bias);
+ cfi_eh = dwfl_module_eh_cfi (mod, &cfi_eh_bias);
+
+ assert (cfi_debug_bias == 0); // No bias needed, same file.
+
+ // We are a bit forgiving for object files. There might be
+ // relocations we don't handle that are needed in some
+ // places...
+ GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (elf, &ehdr_mem);
+ is_ET_REL = ehdr->e_type == ET_REL;
+
+ // Get the actual CU DIE and walk all all DIEs (or just the
+ // 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 (exprlocs)
+ {
+ Dwarf_Addr entrypc;
+ if (dwarf_entrypc (cu, &entrypc) != 0)
+ entrypc = 0;
+
+ /* XXX - Passing true for has_frame_base is not really true.
+ We do it because we want to resolve all DIEs and all
+ attributes. Technically we should check that the DIE
+ (types) are referenced from variables that are defined in
+ a context (function) that has a frame base. */
+ handle_die (cu, 0, true /* Should be false */, entrypc);
+ }
+ else if (dwarf_getfuncs (cu, handle_function, NULL, 0) != 0)
+ error (EXIT_FAILURE, 0, "dwarf_getfuncs %s",
+ dwarf_errmsg (-1));
+ }
+ }
+
+ if (! found_cu)
+ error (EXIT_FAILURE, 0, "No DWARF CU found?");
+
+ dwfl_end (dwfl);
+ return 0;
+}