Merge GDB 7.5.1

gdb/go-lang.c

+/* Go language support routines for GDB, the GNU debugger.
+
+   Copyright (C) 2012 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* TODO:
+   - split stacks
+   - printing of native types
+   - goroutines
+   - lots more
+   - gccgo mangling needs redoing
+     It's too hard, for example, to know whether one is looking at a mangled
+     Go symbol or not, and their are ambiguities, e.g., the demangler may
+     get passed *any* symbol, including symbols from other languages
+     and including symbols that are already demangled.
+     One thought is to at least add an _G prefix.
+   - 6g mangling isn't supported yet
+*/
+
+#include "defs.h"
+#include "gdb_assert.h"
+#include "gdb_obstack.h"
+#include "gdb_string.h"
+#include "block.h"
+#include "symtab.h"
+#include "language.h"
+#include "go-lang.h"
+#include "c-lang.h"
+#include "parser-defs.h"
+
+#include <ctype.h>
+
+/* The main function in the main package.  */
+static const char GO_MAIN_MAIN[] = "main.main";
+
+/* Function returning the special symbol name used by Go for the main
+   procedure in the main program if it is found in minimal symbol list.
+   This function tries to find minimal symbols so that it finds them even
+   if the program was compiled without debugging information.  */
+
+const char *
+go_main_name (void)
+{
+  struct minimal_symbol *msym;
+
+  msym = lookup_minimal_symbol (GO_MAIN_MAIN, NULL, NULL);
+  if (msym != NULL)
+    return GO_MAIN_MAIN;
+
+  /* No known entry procedure found, the main program is probably not Go.  */
+  return NULL;
+}
+
+/* Return non-zero if TYPE is a gccgo string.
+   We assume CHECK_TYPEDEF has already been done.  */
+
+static int
+gccgo_string_p (struct type *type)
+{
+  /* gccgo strings don't necessarily have a name we can use.  */
+
+  if (TYPE_NFIELDS (type) == 2)
+    {
+      struct type *type0 = TYPE_FIELD_TYPE (type, 0);
+      struct type *type1 = TYPE_FIELD_TYPE (type, 1);
+
+      CHECK_TYPEDEF (type0);
+      CHECK_TYPEDEF (type1);
+
+      if (TYPE_CODE (type0) == TYPE_CODE_PTR
+          && strcmp (TYPE_FIELD_NAME (type, 0), "__data") == 0
+          && TYPE_CODE (type1) == TYPE_CODE_INT
+          && strcmp (TYPE_FIELD_NAME (type, 1), "__length") == 0)
+        {
+          struct type *target_type = TYPE_TARGET_TYPE (type0);
+
+          CHECK_TYPEDEF (target_type);
+
+          if (TYPE_CODE (target_type) == TYPE_CODE_INT
+              && TYPE_LENGTH (target_type) == 1
+              && strcmp (TYPE_NAME (target_type), "uint8") == 0)
+            return 1;
+        }
+    }
+
+  return 0;
+}
+
+/* Return non-zero if TYPE is a 6g string.
+   We assume CHECK_TYPEDEF has already been done.  */
+
+static int
+sixg_string_p (struct type *type)
+{
+  if (TYPE_NFIELDS (type) == 2
+      && TYPE_TAG_NAME (type) != NULL
+      && strcmp (TYPE_TAG_NAME (type), "string") == 0)
+    return 1;
+
+  return 0;
+}
+
+/* Classify the kind of Go object that TYPE is.
+   TYPE is a TYPE_CODE_STRUCT, used to represent a Go object.  */
+
+enum go_type
+go_classify_struct_type (struct type *type)
+{
+  CHECK_TYPEDEF (type);
+
+  /* Recognize strings as they're useful to be able to print without
+     pretty-printers.  */
+  if (gccgo_string_p (type)
+      || sixg_string_p (type))
+    return GO_TYPE_STRING;
+
+  return GO_TYPE_NONE;
+}
+
+/* Subroutine of unpack_mangled_go_symbol to simplify it.
+   Given "[foo.]bar.baz", store "bar" in *PACKAGEP and "baz" in *OBJECTP.
+   We stomp on the last '.' to nul-terminate "bar".
+   The caller is responsible for memory management.  */
+
+static void
+unpack_package_and_object (char *buf,
+                           const char **packagep, const char **objectp)
+{
+  char *last_dot;
+
+  last_dot = strrchr (buf, '.');
+  gdb_assert (last_dot != NULL);
+  *objectp = last_dot + 1;
+  *last_dot = '\0';
+  last_dot = strrchr (buf, '.');
+  if (last_dot != NULL)
+    *packagep = last_dot + 1;
+  else
+    *packagep = buf;
+}
+
+/* Given a mangled Go symbol, find its package name, object name, and
+   method type (if present).
+   E.g., for "libgo_net.textproto.String.N33_libgo_net.textproto.ProtocolError"
+   *PACKAGEP = "textproto"
+   *OBJECTP = "String"
+   *METHOD_TYPE_PACKAGEP = "textproto"
+   *METHOD_TYPE_OBJECTP = "ProtocolError"
+
+   Space for the resulting strings is malloc'd in one buffer.
+   PACKAGEP,OBJECTP,METHOD_TYPE* will (typically) point into this buffer.
+   [There are a few exceptions, but the caller is still responsible for
+   freeing the resulting pointer.]
+   A pointer to this buffer is returned, or NULL if symbol isn't a
+   mangled Go symbol.
+   The caller is responsible for freeing the result.
+
+   *METHOD_TYPE_IS_POINTERP is set to a boolean indicating if
+   the method type is a pointer.
+
+   There may be value in returning the outer container,
+   i.e., "net" in the above example, but for now it's not needed.
+   Plus it's currently not straightforward to compute,
+   it comes from -fgo-prefix, and there's no algorithm to compute it.
+
+   If we ever need to unpack the method type, this routine should work
+   for that too.  */
+
+static char *
+unpack_mangled_go_symbol (const char *mangled_name,
+                          const char **packagep,
+                          const char **objectp,
+                          const char **method_type_packagep,
+                          const char **method_type_objectp,
+                          int *method_type_is_pointerp)
+{
+  char *buf;
+  char *p;
+  int len = strlen (mangled_name);
+  /* Pointer to last digit in "N<digit(s)>_".  */
+  char *saw_digit;
+  /* Pointer to "N" if valid "N<digit(s)>_" found.  */
+  char *method_type;
+  /* Pointer to the first '.'.  */
+  char *first_dot;
+  /* Pointer to the last '.'.  */
+  char *last_dot;
+  /* Non-zero if we saw a pointer indicator.  */
+  int saw_pointer;
+
+  *packagep = *objectp = NULL;
+  *method_type_packagep = *method_type_objectp = NULL;
+  *method_type_is_pointerp = 0;
+
+  /* main.init is mangled specially.  */
+  if (strcmp (mangled_name, "__go_init_main") == 0)
+    {
+      char *package = xstrdup ("main");
+
+      *packagep = package;
+      *objectp = "init";
+      return package;
+    }
+
+  /* main.main is mangled specially (missing prefix).  */
+  if (strcmp (mangled_name, "main.main") == 0)
+    {
+      char *package = xstrdup ("main");
+
+      *packagep = package;
+      *objectp = "main";
+      return package;
+    }
+
+  /* We may get passed, e.g., "main.T.Foo", which is *not* mangled.
+     Alas it looks exactly like "prefix.package.object."
+     To cope for now we only recognize the following prefixes:
+
+     go: the default
+     libgo_.*: used by gccgo's runtime
+
+     Thus we don't support -fgo-prefix (except as used by the runtime).  */
+  if (strncmp (mangled_name, "go.", 3) != 0
+      && strncmp (mangled_name, "libgo_", 6) != 0)
+    return NULL;
+
+  /* Quick check for whether a search may be fruitful.  */
+  /* Ignore anything with @plt, etc. in it.  */
+  if (strchr (mangled_name, '@') != NULL)
+    return NULL;
+  /* It must have at least two dots.  */
+  first_dot = strchr (mangled_name, '.');
+  if (first_dot == NULL)
+    return NULL;
+  /* Treat "foo.bar" as unmangled.  It can collide with lots of other
+     languages and it's not clear what the consequences are.
+     And except for main.main, all gccgo symbols are at least
+     prefix.package.object.  */
+  last_dot = strrchr (mangled_name, '.');
+  if (last_dot == first_dot)
+    return NULL;
+
+  /* More quick checks.  */
+  if (last_dot[1] == '\0' /* foo. */
+      || last_dot[-1] == '.') /* foo..bar */
+    return NULL;
+
+  /* At this point we've decided we have a mangled Go symbol.  */
+
+  buf = xstrdup (mangled_name);
+
+  /* Search backwards looking for "N<digit(s)>".  */
+  p = buf + len;
+  saw_digit = method_type = NULL;
+  saw_pointer = 0;
+  while (p > buf)
+    {
+      int current = *(const unsigned char *) --p;
+      int current_is_digit = isdigit (current);
+
+      if (saw_digit)
+        {
+          if (current_is_digit)
+            continue;
+          if (current == 'N'
+              && ((p > buf && p[-1] == '.')
+                  || (p > buf + 1 && p[-1] == 'p' && p[-2] == '.')))
+            {
+              if (atoi (p + 1) == strlen (saw_digit + 2))
+                {
+                  if (p[-1] == '.')
+                    method_type = p - 1;
+                  else
+                    {
+                      gdb_assert (p[-1] == 'p');
+                      saw_pointer = 1;
+                      method_type = p - 2;
+                    }
+                  break;
+                }
+            }
+          /* Not what we're looking for, reset and keep looking.  */
+          saw_digit = NULL;
+          saw_pointer = 0;
+          continue;
+        }
+      if (current_is_digit && p[1] == '_')
+        {
+          /* Possible start of method "this" [sic] type.  */
+          saw_digit = p;
+          continue;
+        }
+    }
+
+  if (method_type != NULL
+      /* Ensure not something like "..foo".  */
+      && (method_type > buf && method_type[-1] != '.'))
+    {
+      unpack_package_and_object (saw_digit + 2,
+                                 method_type_packagep, method_type_objectp);
+      *method_type = '\0';
+      *method_type_is_pointerp = saw_pointer;
+    }
+
+  unpack_package_and_object (buf, packagep, objectp);
+  return buf;
+}
+
+/* Implements the la_demangle language_defn routine for language Go.
+
+   N.B. This may get passed *any* symbol, including symbols from other
+   languages and including symbols that are already demangled.
+   Both of these situations are kinda unfortunate, but that's how things
+   are today.
+
+   N.B. This currently only supports gccgo's mangling.
+
+   N.B. gccgo's mangling needs, I think, changing.
+   This demangler can't work in all situations,
+   thus not too much effort is currently put into it.  */
+
+char *
+go_demangle (const char *mangled_name, int options)
+{
+  struct obstack tempbuf;
+  char *result;
+  char *name_buf;
+  const char *package_name;
+  const char *object_name;
+  const char *method_type_package_name;
+  const char *method_type_object_name;
+  int method_type_is_pointer;
+
+  if (mangled_name == NULL)
+    return NULL;
+
+  name_buf = unpack_mangled_go_symbol (mangled_name,
+                                       &package_name, &object_name,
+                                       &method_type_package_name,
+                                       &method_type_object_name,
+                                       &method_type_is_pointer);
+  if (name_buf == NULL)
+    return NULL;
+
+  obstack_init (&tempbuf);
+
+  /* Print methods as they appear in "method expressions".  */
+  if (method_type_package_name != NULL)
+    {
+      /* FIXME: Seems like we should include package_name here somewhere.  */
+      if (method_type_is_pointer)
+          obstack_grow_str (&tempbuf, "(*");
+      obstack_grow_str (&tempbuf, method_type_package_name);
+      obstack_grow_str (&tempbuf, ".");
+      obstack_grow_str (&tempbuf, method_type_object_name);
+      if (method_type_is_pointer)
+        obstack_grow_str (&tempbuf, ")");
+      obstack_grow_str (&tempbuf, ".");
+      obstack_grow_str (&tempbuf, object_name);
+    }
+  else
+    {
+      obstack_grow_str (&tempbuf, package_name);
+      obstack_grow_str (&tempbuf, ".");
+      obstack_grow_str (&tempbuf, object_name);
+    }
+  obstack_grow_str0 (&tempbuf, "");
+
+  result = xstrdup (obstack_finish (&tempbuf));
+  obstack_free (&tempbuf, NULL);
+  xfree (name_buf);
+  return result;
+}
+
+/* Given a Go symbol, return its package or NULL if unknown.
+   Space for the result is malloc'd, caller must free.  */
+
+char *
+go_symbol_package_name (const struct symbol *sym)
+{
+  const char *mangled_name = SYMBOL_LINKAGE_NAME (sym);
+  const char *package_name;
+  const char *object_name;
+  const char *method_type_package_name;
+  const char *method_type_object_name;
+  int method_type_is_pointer;
+  char *name_buf;
+  char *result;
+
+  gdb_assert (SYMBOL_LANGUAGE (sym) == language_go);
+  name_buf = unpack_mangled_go_symbol (mangled_name,
+                                       &package_name, &object_name,
+                                       &method_type_package_name,
+                                       &method_type_object_name,
+                                       &method_type_is_pointer);
+  /* Some Go symbols don't have mangled form we interpret (yet).  */
+  if (name_buf == NULL)
+    return NULL;
+  result = xstrdup (package_name);
+  xfree (name_buf);
+  return result;
+}
+
+/* Return the package that BLOCK is in, or NULL if there isn't one.
+   Space for the result is malloc'd, caller must free.  */
+
+char *
+go_block_package_name (const struct block *block)
+{
+  while (block != NULL)
+    {
+      struct symbol *function = BLOCK_FUNCTION (block);
+
+      if (function != NULL)
+        {
+          char *package_name = go_symbol_package_name (function);
+
+          if (package_name != NULL)
+            return package_name;
+
+          /* Stop looking if we find a function without a package name.
+             We're most likely outside of Go and thus the concept of the
+             "current" package is gone.  */
+          return NULL;
+        }
+
+      block = BLOCK_SUPERBLOCK (block);
+    }
+
+  return NULL;
+}
+
+/* Table mapping opcodes into strings for printing operators
+   and precedences of the operators.
+   TODO(dje): &^ ?  */
+
+static const struct op_print go_op_print_tab[] =
+{
+  {",", BINOP_COMMA, PREC_COMMA, 0},
+  {"=", BINOP_ASSIGN, PREC_ASSIGN, 1},
+  {"||", BINOP_LOGICAL_OR, PREC_LOGICAL_OR, 0},
+  {"&&", BINOP_LOGICAL_AND, PREC_LOGICAL_AND, 0},
+  {"|", BINOP_BITWISE_IOR, PREC_BITWISE_IOR, 0},
+  {"^", BINOP_BITWISE_XOR, PREC_BITWISE_XOR, 0},
+  {"&", BINOP_BITWISE_AND, PREC_BITWISE_AND, 0},
+  {"==", BINOP_EQUAL, PREC_EQUAL, 0},
+  {"!=", BINOP_NOTEQUAL, PREC_EQUAL, 0},
+  {"<=", BINOP_LEQ, PREC_ORDER, 0},
+  {">=", BINOP_GEQ, PREC_ORDER, 0},
+  {">", BINOP_GTR, PREC_ORDER, 0},
+  {"<", BINOP_LESS, PREC_ORDER, 0},
+  {">>", BINOP_RSH, PREC_SHIFT, 0},
+  {"<<", BINOP_LSH, PREC_SHIFT, 0},
+  {"+", BINOP_ADD, PREC_ADD, 0},
+  {"-", BINOP_SUB, PREC_ADD, 0},
+  {"*", BINOP_MUL, PREC_MUL, 0},
+  {"/", BINOP_DIV, PREC_MUL, 0},
+  {"%", BINOP_REM, PREC_MUL, 0},
+  {"@", BINOP_REPEAT, PREC_REPEAT, 0},
+  {"-", UNOP_NEG, PREC_PREFIX, 0},
+  {"!", UNOP_LOGICAL_NOT, PREC_PREFIX, 0},
+  {"^", UNOP_COMPLEMENT, PREC_PREFIX, 0},
+  {"*", UNOP_IND, PREC_PREFIX, 0},
+  {"&", UNOP_ADDR, PREC_PREFIX, 0},
+  {"unsafe.Sizeof ", UNOP_SIZEOF, PREC_PREFIX, 0},
+  {"++", UNOP_POSTINCREMENT, PREC_SUFFIX, 0},
+  {"--", UNOP_POSTDECREMENT, PREC_SUFFIX, 0},
+  {NULL, 0, 0, 0}
+};
+
+enum go_primitive_types {
+  go_primitive_type_void,
+  go_primitive_type_char,
+  go_primitive_type_bool,
+  go_primitive_type_int,
+  go_primitive_type_uint,
+  go_primitive_type_uintptr,
+  go_primitive_type_int8,
+  go_primitive_type_int16,
+  go_primitive_type_int32,
+  go_primitive_type_int64,
+  go_primitive_type_uint8,
+  go_primitive_type_uint16,
+  go_primitive_type_uint32,
+  go_primitive_type_uint64,
+  go_primitive_type_float32,
+  go_primitive_type_float64,
+  go_primitive_type_complex64,
+  go_primitive_type_complex128,
+  nr_go_primitive_types
+};
+
+static void
+go_language_arch_info (struct gdbarch *gdbarch,
+                       struct language_arch_info *lai)
+{
+  const struct builtin_go_type *builtin = builtin_go_type (gdbarch);
+
+  lai->string_char_type = builtin->builtin_char;
+
+  lai->primitive_type_vector
+    = GDBARCH_OBSTACK_CALLOC (gdbarch, nr_go_primitive_types + 1,
+                              struct type *);
+
+  lai->primitive_type_vector [go_primitive_type_void]
+    = builtin->builtin_void;
+  lai->primitive_type_vector [go_primitive_type_char]
+    = builtin->builtin_char;
+  lai->primitive_type_vector [go_primitive_type_bool]
+    = builtin->builtin_bool;
+  lai->primitive_type_vector [go_primitive_type_int]
+    = builtin->builtin_int;
+  lai->primitive_type_vector [go_primitive_type_uint]
+    = builtin->builtin_uint;
+  lai->primitive_type_vector [go_primitive_type_uintptr]
+    = builtin->builtin_uintptr;
+  lai->primitive_type_vector [go_primitive_type_int8]
+    = builtin->builtin_int8;
+  lai->primitive_type_vector [go_primitive_type_int16]
+    = builtin->builtin_int16;
+  lai->primitive_type_vector [go_primitive_type_int32]
+    = builtin->builtin_int32;
+  lai->primitive_type_vector [go_primitive_type_int64]
+    = builtin->builtin_int64;
+  lai->primitive_type_vector [go_primitive_type_uint8]
+    = builtin->builtin_uint8;
+  lai->primitive_type_vector [go_primitive_type_uint16]
+    = builtin->builtin_uint16;
+  lai->primitive_type_vector [go_primitive_type_uint32]
+    = builtin->builtin_uint32;
+  lai->primitive_type_vector [go_primitive_type_uint64]
+    = builtin->builtin_uint64;
+  lai->primitive_type_vector [go_primitive_type_float32]
+    = builtin->builtin_float32;
+  lai->primitive_type_vector [go_primitive_type_float64]
+    = builtin->builtin_float64;
+  lai->primitive_type_vector [go_primitive_type_complex64]
+    = builtin->builtin_complex64;
+  lai->primitive_type_vector [go_primitive_type_complex128]
+    = builtin->builtin_complex128;
+
+  lai->bool_type_symbol = "bool";
+  lai->bool_type_default = builtin->builtin_bool;
+}
+
+static const struct language_defn go_language_defn =
+{
+  "go",
+  language_go,
+  range_check_off,
+  type_check_off,
+  case_sensitive_on,
+  array_row_major,
+  macro_expansion_no,
+  &exp_descriptor_c,
+  go_parse,
+  go_error,
+  null_post_parser,
+  c_printchar,                  /* Print a character constant.  */
+  c_printstr,                   /* Function to print string constant.  */
+  c_emit_char,                  /* Print a single char.  */
+  go_print_type,                /* Print a type using appropriate syntax.  */
+  c_print_typedef,              /* Print a typedef using appropriate
+                                   syntax.  */
+  go_val_print,                 /* Print a value using appropriate syntax.  */
+  c_value_print,                /* Print a top-level value.  */
+  default_read_var_value,       /* la_read_var_value */
+  NULL,                         /* Language specific skip_trampoline.  */
+  NULL,                         /* name_of_this */
+  basic_lookup_symbol_nonlocal, 
+  basic_lookup_transparent_type,
+  go_demangle,                  /* Language specific symbol demangler.  */
+  NULL,                         /* Language specific
+                                   class_name_from_physname.  */
+  go_op_print_tab,              /* Expression operators for printing.  */
+  1,                            /* C-style arrays.  */
+  0,                            /* String lower bound.  */
+  default_word_break_characters,
+  default_make_symbol_completion_list,
+  go_language_arch_info,
+  default_print_array_index,
+  default_pass_by_reference,
+  c_get_string,
+  NULL,
+  iterate_over_symbols,
+  LANG_MAGIC
+};
+
+static void *
+build_go_types (struct gdbarch *gdbarch)
+{
+  struct builtin_go_type *builtin_go_type
+    = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct builtin_go_type);
+
+  builtin_go_type->builtin_void
+    = arch_type (gdbarch, TYPE_CODE_VOID, 1, "void");
+  builtin_go_type->builtin_char
+    = arch_character_type (gdbarch, 8, 1, "char");
+  builtin_go_type->builtin_bool
+    = arch_boolean_type (gdbarch, 8, 0, "bool");
+  builtin_go_type->builtin_int
+    = arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch), 0, "int");
+  builtin_go_type->builtin_uint
+    = arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch), 1, "uint");
+  builtin_go_type->builtin_uintptr
+    = arch_integer_type (gdbarch, gdbarch_ptr_bit (gdbarch), 1, "uintptr");
+  builtin_go_type->builtin_int8
+    = arch_integer_type (gdbarch, 8, 0, "int8");
+  builtin_go_type->builtin_int16
+    = arch_integer_type (gdbarch, 16, 0, "int16");
+  builtin_go_type->builtin_int32
+    = arch_integer_type (gdbarch, 32, 0, "int32");
+  builtin_go_type->builtin_int64
+    = arch_integer_type (gdbarch, 64, 0, "int64");
+  builtin_go_type->builtin_uint8
+    = arch_integer_type (gdbarch, 8, 1, "uint8");
+  builtin_go_type->builtin_uint16
+    = arch_integer_type (gdbarch, 16, 1, "uint16");
+  builtin_go_type->builtin_uint32
+    = arch_integer_type (gdbarch, 32, 1, "uint32");
+  builtin_go_type->builtin_uint64
+    = arch_integer_type (gdbarch, 64, 1, "uint64");
+  builtin_go_type->builtin_float32
+    = arch_float_type (gdbarch, 32, "float32", NULL);
+  builtin_go_type->builtin_float64
+    = arch_float_type (gdbarch, 64, "float64", NULL);
+  builtin_go_type->builtin_complex64
+    = arch_complex_type (gdbarch, "complex64",
+                         builtin_go_type->builtin_float32);
+  builtin_go_type->builtin_complex128
+    = arch_complex_type (gdbarch, "complex128",
+                         builtin_go_type->builtin_float64);
+
+  return builtin_go_type;
+}
+
+static struct gdbarch_data *go_type_data;
+
+const struct builtin_go_type *
+builtin_go_type (struct gdbarch *gdbarch)
+{
+  return gdbarch_data (gdbarch, go_type_data);
+}
+
+extern initialize_file_ftype _initialize_go_language;
+
+void
+_initialize_go_language (void)
+{
+  go_type_data = gdbarch_data_register_post_init (build_go_types);
+
+  add_language (&go_language_defn);
+}