Stop assuming no-debug-info variables have type int

An earlier commit made GDB no longer assume no-debug-info functions
return int.  This commit gives the same treatment to variables.

Currently, you can end misled by GDB over output like this:

  (gdb) p var
  $1 = -1
  (gdb) p /x var
  $2 = 0xffffffff

until you realize that GDB is assuming that the variable is an "int",
because:

  (gdb) ptype var
  type = <data variable, no debug info>

You may try to fix it by casting, but that doesn't really help:

  (gdb) p /x (unsigned long long) var
  $3 = 0xffffffffffffffff            # incorrect
         ^^

That's incorrect output, because the variable was defined like this:

  uint64_t var = 0x7fffffffffffffff;
                   ^^

What happened is that with the cast, GDB did an int -> 'unsigned long
long' conversion instead of reinterpreting the variable as the cast-to
type.  To get at the variable properly you have to reinterpret the
variable's address manually instead, with either:

  (gdb) p /x *(unsigned long long *) &var
  $4 = 0x7fffffffffffffff
  (gdb) p /x {unsigned long long} &var
  $5 = 0x7fffffffffffffff

After this commit GDB does it for you.  This is what you'll get
instead:

  (gdb) p var
  'var' has unknown type; cast it to its declared type
  (gdb) p /x (unsigned long long) var
  $1 = 0x7fffffffffffffff

As in the functions patch, the "compile" machinery doesn't currently
have the cast-to type handy, so it continues assuming no-debug
variables have int type, though now at least it warns.

The change to gdb.cp/m-static.exp deserves an explanation:

 - gdb_test "print 'gnu_obj_1::method()::sintvar'" "\\$\[0-9\]+ = 4" \
 + gdb_test "print (int) 'gnu_obj_1::method()::sintvar'" "\\$\[0-9\]+ = 4" \

That's printing the "sintvar" function local static of the
"gnu_obj_1::method()" method.

The problem with that test is that that "'S::method()::static_var'"
syntax doesn't really work in C++ as you'd expect.  The way to make it
work correctly currently is to quote the method part, not the whole
expression, like:

  (gdb) print 'gnu_obj_1::method()'::sintvar

If you wrap the whole expression in quotes, like in m-static.exp, what
really happens is that the parser considers the whole string as a
symbol name, but there's no debug symbol with that name.  However,
local statics have linkage and are given a mangled name that demangles
to the same string as the full expression, so that's what GDB prints.
After this commit, and without the cast, the print in m-static.exp
would error out saying that the variable has unknown type:

  (gdb) p 'gnu_obj_1::method()::sintvar'
  'gnu_obj_1::method()::sintvar' has unknown type; cast it to its declared type

TBC, if currently (even before this series) you try to print any
function local static variable of type other than int, you'll get
bogus results.  You can see that with m-static.cc as is, even.
Printing the "svar" local, which is a boolean (1 byte) still prints as
"int" (4 bytes):

  (gdb) p 'gnu_obj_1::method()::svar'
  $1 = 1
  (gdb) ptype 'gnu_obj_1::method()::svar'
  type = <data variable, no debug info>

This probably prints some random bogus value on big endian machines.

If 'svar' was of some aggregate type (etc.) we'd still print it as
int, so the problem would have been more obvious...  After this
commit, you'll get instead:

  (gdb) p 'gnu_obj_1::method()::svar'
  'gnu_obj_1::method()::svar' has unknown type; cast it to its declared type

... so at least GDB is no longer misleading.  Making GDB find the real
local static debug symbol is the subject of the following patches.  In
the end, it'll all "Just Work".

gdb/ChangeLog:
2017-09-04  Pedro Alves  <palves@redhat.com>

	* ax-gdb.c: Include "typeprint.h".
	(gen_expr_for_cast): New function.
	(gen_expr) <OP_CAST, OP_CAST_TYPE>: Use it.
	<OP_VAR_VALUE, OP_MSYM_VAR_VALUE>: Error out if the variable's
	type is unknown.
	* dwarf2read.c (new_symbol_full): Fallback to int instead of
	nodebug_data_symbol.
	* eval.c: Include "typeprint.h".
	(evaluate_subexp_standard) <OP_VAR_VALUE, OP_VAR_MSYM_VALUE>:
	Error out if symbol has unknown type.
	<UNOP_CAST, UNOP_CAST_TYPE>: Common bits factored out to
	evaluate_subexp_for_cast.
	(evaluate_subexp_for_address, evaluate_subexp_for_sizeof): Handle
	OP_VAR_MSYM_VALUE.
	(evaluate_subexp_for_cast): New function.
	* gdbtypes.c (init_nodebug_var_type): New function.
	(objfile_type): Use it to initialize types of variables with no
	debug info.
	* typeprint.c (error_unknown_type): New.
	* typeprint.h (error_unknown_type): New declaration.
	* compile/compile-c-types.c (convert_type_basic): Handle
	TYPE_CODE_ERROR; warn and fallback to int for variables with
	unknown type.

gdb/testsuite/ChangeLog:
2017-09-04  Pedro Alves  <palves@redhat.com>

	* gdb.asm/asm-source.exp: Add casts to int.
	* gdb.base/nodebug.c (dataglobal8, dataglobal32_1, dataglobal32_2)
	(dataglobal64_1, dataglobal64_2): New globals.
	* gdb.base/nodebug.exp: Test different expressions involving the
	new globals, with print, whatis and ptype.  Add casts to int.
	* gdb.base/solib-display.exp: Add casts to int.
	* gdb.compile/compile-ifunc.exp: Expect warning.  Add cast to int.
	* gdb.cp/m-static.exp: Add cast to int.
	* gdb.dwarf2/dw2-skip-prologue.exp: Add cast to int.
	* gdb.threads/tls-nodebug.exp: Check that gdb errors out printing
	tls variable with no debug info without a cast.  Test with a cast
	to int too.
	* gdb.trace/entry-values.exp: Add casts.

18 files changed, 343 insertions, 68 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7859c647316..4e08489c49d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,31 @@
 2017-09-04  Pedro Alves  <palves@redhat.com>
 
+	* ax-gdb.c: Include "typeprint.h".
+	(gen_expr_for_cast): New function.
+	(gen_expr) <OP_CAST, OP_CAST_TYPE>: Use it.
+	<OP_VAR_VALUE, OP_MSYM_VAR_VALUE>: Error out if the variable's
+	type is unknown.
+	* dwarf2read.c (new_symbol_full): Fallback to int instead of
+	nodebug_data_symbol.
+	* eval.c: Include "typeprint.h".
+	(evaluate_subexp_standard) <OP_VAR_VALUE, OP_VAR_MSYM_VALUE>:
+	Error out if symbol has unknown type.
+	<UNOP_CAST, UNOP_CAST_TYPE>: Common bits factored out to
+	evaluate_subexp_for_cast.
+	(evaluate_subexp_for_address, evaluate_subexp_for_sizeof): Handle
+	OP_VAR_MSYM_VALUE.
+	(evaluate_subexp_for_cast): New function.
+	* gdbtypes.c (init_nodebug_var_type): New function.
+	(objfile_type): Use it to initialize types of variables with no
+	debug info.
+	* typeprint.c (error_unknown_type): New.
+	* typeprint.h (error_unknown_type): New declaration.
+	* compile/compile-c-types.c (convert_type_basic): Handle
+	TYPE_CODE_ERROR; warn and fallback to int for variables with
+	unknown type.
+
+2017-09-04  Pedro Alves  <palves@redhat.com>
+
 	* eval.c (evaluate_var_value): New function, factored out from ...
 	(evaluate_subexp_standard): ... here.
 
diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 3fdf81afee5..2b5e481dc01 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -42,7 +42,7 @@
 #include "linespec.h"
 #include "location.h"
 #include "objfiles.h"
-
+#include "typeprint.h"
 #include "valprint.h"
 #include "c-lang.h"
 
@@ -1765,6 +1765,40 @@ gen_sizeof (struct expression *exp, union exp_element **pc,
 }
 
 
+/* Generate bytecode for a cast to TO_TYPE.  Advance *PC over the
+   subexpression.  */
+
+static void
+gen_expr_for_cast (struct expression *exp, union exp_element **pc,
+		   struct agent_expr *ax, struct axs_value *value,
+		   struct type *to_type)
+{
+  enum exp_opcode op = (*pc)[0].opcode;
+
+  /* Don't let symbols be handled with gen_expr because that throws an
+     "unknown type" error for no-debug data symbols.  Instead, we want
+     the cast to reinterpret such symbols.  */
+  if (op == OP_VAR_MSYM_VALUE || op == OP_VAR_VALUE)
+    {
+      if (op == OP_VAR_VALUE)
+	{
+	  gen_var_ref (ax, value, (*pc)[2].symbol);
+
+	  if (value->optimized_out)
+	    error (_("`%s' has been optimized out, cannot use"),
+		   SYMBOL_PRINT_NAME ((*pc)[2].symbol));
+	}
+      else
+	gen_msym_var_ref (ax, value, (*pc)[2].msymbol, (*pc)[1].objfile);
+      if (TYPE_CODE (value->type) == TYPE_CODE_ERROR)
+	value->type = to_type;
+      (*pc) += 4;
+    }
+  else
+    gen_expr (exp, pc, ax, value);
+  gen_cast (ax, value, to_type);
+}
+
 /* Generating bytecode from GDB expressions: general recursive thingy  */
 
 /* XXX: i18n */
@@ -1978,11 +2012,18 @@ gen_expr (struct expression *exp, union exp_element **pc,
 	error (_("`%s' has been optimized out, cannot use"),
 	       SYMBOL_PRINT_NAME ((*pc)[2].symbol));
 
+      if (TYPE_CODE (value->type) == TYPE_CODE_ERROR)
+	error_unknown_type (SYMBOL_PRINT_NAME ((*pc)[2].symbol));
+
       (*pc) += 4;
       break;
 
     case OP_VAR_MSYM_VALUE:
       gen_msym_var_ref (ax, value, (*pc)[2].msymbol, (*pc)[1].objfile);
+
+      if (TYPE_CODE (value->type) == TYPE_CODE_ERROR)
+	error_unknown_type (MSYMBOL_PRINT_NAME ((*pc)[2].msymbol));
+
       (*pc) += 4;
       break;
 
@@ -2043,8 +2084,7 @@ gen_expr (struct expression *exp, union exp_element **pc,
 	struct type *type = (*pc)[1].type;
 
 	(*pc) += 3;
-	gen_expr (exp, pc, ax, value);
-	gen_cast (ax, value, type);
+	gen_expr_for_cast (exp, pc, ax, value, type);
       }
       break;
 
@@ -2059,9 +2099,7 @@ gen_expr (struct expression *exp, union exp_element **pc,
 	val = evaluate_subexp (NULL, exp, &offset, EVAL_AVOID_SIDE_EFFECTS);
 	type = value_type (val);
 	*pc = &exp->elts[offset];
-
-	gen_expr (exp, pc, ax, value);
-	gen_cast (ax, value, type);
+	gen_expr_for_cast (exp, pc, ax, value, type);
       }
       break;
 
diff --git a/gdb/compile/compile-c-types.c b/gdb/compile/compile-c-types.c
index 2bfa72d2b8c..b53a3c45dcf 100644
--- a/gdb/compile/compile-c-types.c
+++ b/gdb/compile/compile-c-types.c
@@ -383,6 +383,21 @@ convert_type_basic (struct compile_c_instance *context, struct type *type)
 
     case TYPE_CODE_COMPLEX:
       return convert_complex (context, type);
+
+    case TYPE_CODE_ERROR:
+      {
+	/* Ideally, if we get here due to a cast expression, we'd use
+	   the cast-to type as the variable's type, like GDB's
+	   built-in parser does.  For now, assume "int" like GDB's
+	   built-in parser used to do, but at least warn.  */
+	struct type *fallback;
+	if (TYPE_OBJFILE_OWNED (type))
+	  fallback = objfile_type (TYPE_OWNER (type).objfile)->builtin_int;
+	else
+	  fallback = builtin_type (TYPE_OWNER (type).gdbarch)->builtin_int;
+	warning (_("variable has unknown type; assuming int"));
+	return convert_int (context, fallback);
+      }
     }
 
   return C_CTX (context)->c_ops->error (C_CTX (context),
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index ead4f3ca350..893e04d83f5 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -19139,8 +19139,7 @@ new_symbol_full (struct die_info *die, struct type *type, struct dwarf2_cu *cu,
 	     variables with missing type entries.  Change the
 	     misleading `void' type to something sensible.  */
 	  if (TYPE_CODE (SYMBOL_TYPE (sym)) == TYPE_CODE_VOID)
-	    SYMBOL_TYPE (sym)
-	      = objfile_type (objfile)->nodebug_data_symbol;
+	    SYMBOL_TYPE (sym) = objfile_type (objfile)->builtin_int;
 
 	  attr = dwarf2_attr (die, DW_AT_const_value, cu);
 	  /* In the case of DW_TAG_member, we should only be called for
diff --git a/gdb/eval.c b/gdb/eval.c
index a97f4a999e6..75d3c86f123 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -39,6 +39,7 @@
 #include "valprint.h"
 #include "gdb_obstack.h"
 #include "objfiles.h"
+#include "typeprint.h"
 #include <ctype.h>
 
 /* This is defined in valops.c */
@@ -52,6 +53,10 @@ static struct value *evaluate_subexp_for_sizeof (struct expression *, int *,
 static struct value *evaluate_subexp_for_address (struct expression *,
 						  int *, enum noside);
 
+static value *evaluate_subexp_for_cast (expression *exp, int *pos,
+					enum noside noside,
+					struct type *type);
+
 static struct value *evaluate_struct_tuple (struct value *,
 					    struct expression *, int *,
 					    enum noside, int);
@@ -796,14 +801,30 @@ evaluate_subexp_standard (struct type *expect_type,
       (*pos) += 3;
       if (noside == EVAL_SKIP)
 	return eval_skip_value (exp);
-      return evaluate_var_value (noside,
-				 exp->elts[pc + 1].block,
-				 exp->elts[pc + 2].symbol);
+
+      {
+	symbol *var = exp->elts[pc + 2].symbol;
+	if (TYPE_CODE (SYMBOL_TYPE (var)) == TYPE_CODE_ERROR)
+	  error_unknown_type (SYMBOL_PRINT_NAME (var));
+
+	return evaluate_var_value (noside, exp->elts[pc + 1].block, var);
+      }
+
     case OP_VAR_MSYM_VALUE:
-      (*pos) += 3;
-      return evaluate_var_msym_value (noside,
-				      exp->elts[pc + 1].objfile,
-				      exp->elts[pc + 2].msymbol);
+      {
+	(*pos) += 3;
+
+	minimal_symbol *msymbol = exp->elts[pc + 2].msymbol;
+	value *val = evaluate_var_msym_value (noside,
+					      exp->elts[pc + 1].objfile,
+					      msymbol);
+
+	type = value_type (val);
+	if (TYPE_CODE (type) == TYPE_CODE_ERROR
+	    && (noside != EVAL_AVOID_SIDE_EFFECTS || pc != 0))
+	  error_unknown_type (MSYMBOL_PRINT_NAME (msymbol));
+	return val;
+      }
 
     case OP_VAR_ENTRY_VALUE:
       (*pos) += 2;
@@ -2589,22 +2610,12 @@ evaluate_subexp_standard (struct type *expect_type,
     case UNOP_CAST:
       (*pos) += 2;
       type = exp->elts[pc + 1].type;
-      arg1 = evaluate_subexp (type, exp, pos, noside);
-      if (noside == EVAL_SKIP)
-	return eval_skip_value (exp);
-      if (type != value_type (arg1))
-	arg1 = value_cast (type, arg1);
-      return arg1;
+      return evaluate_subexp_for_cast (exp, pos, noside, type);
 
     case UNOP_CAST_TYPE:
       arg1 = evaluate_subexp (NULL, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
       type = value_type (arg1);
-      arg1 = evaluate_subexp (type, exp, pos, noside);
-      if (noside == EVAL_SKIP)
-	return eval_skip_value (exp);
-      if (type != value_type (arg1))
-	arg1 = value_cast (type, arg1);
-      return arg1;
+      return evaluate_subexp_for_cast (exp, pos, noside, type);
 
     case UNOP_DYNAMIC_CAST:
       arg1 = evaluate_subexp (NULL, exp, pos, EVAL_AVOID_SIDE_EFFECTS);
@@ -2927,6 +2938,22 @@ evaluate_subexp_for_address (struct expression *exp, int *pos,
       else
 	return address_of_variable (var, exp->elts[pc + 1].block);
 
+    case OP_VAR_MSYM_VALUE:
+      {
+	(*pos) += 4;
+
+	value *val = evaluate_var_msym_value (noside,
+					      exp->elts[pc + 1].objfile,
+					      exp->elts[pc + 2].msymbol);
+	if (noside == EVAL_AVOID_SIDE_EFFECTS)
+	  {
+	    struct type *type = lookup_pointer_type (value_type (val));
+	    return value_zero (type, not_lval);
+	  }
+	else
+	  return value_addr (val);
+      }
+
     case OP_SCOPE:
       tem = longest_to_int (exp->elts[pc + 2].longconst);
       (*pos) += 5 + BYTES_TO_EXP_ELEM (tem + 1);
@@ -3065,6 +3092,23 @@ evaluate_subexp_for_sizeof (struct expression *exp, int *pos,
 	(*pos) += 4;
       break;
 
+    case OP_VAR_MSYM_VALUE:
+      {
+	(*pos) += 4;
+
+	minimal_symbol *msymbol = exp->elts[pc + 2].msymbol;
+	value *val = evaluate_var_msym_value (noside,
+					      exp->elts[pc + 1].objfile,
+					      msymbol);
+
+	type = value_type (val);
+	if (TYPE_CODE (type) == TYPE_CODE_ERROR)
+	  error_unknown_type (MSYMBOL_PRINT_NAME (msymbol));
+
+	return value_from_longest (size_type, TYPE_LENGTH (type));
+      }
+      break;
+
       /* Deal with the special case if NOSIDE is EVAL_NORMAL and the resulting
 	 type of the subscript is a variable length array type. In this case we
 	 must re-evaluate the right hand side of the subcription to allow
@@ -3112,6 +3156,61 @@ evaluate_subexp_for_sizeof (struct expression *exp, int *pos,
   return value_from_longest (size_type, (LONGEST) TYPE_LENGTH (type));
 }
 
+/* Evaluate a subexpression of EXP, at index *POS, and return a value
+   for that subexpression cast to TO_TYPE.  Advance *POS over the
+   subexpression.  */
+
+static value *
+evaluate_subexp_for_cast (expression *exp, int *pos,
+			  enum noside noside,
+			  struct type *to_type)
+{
+  int pc = *pos;
+
+  /* Don't let symbols be evaluated with evaluate_subexp because that
+     throws an "unknown type" error for no-debug data symbols.
+     Instead, we want the cast to reinterpret the symbol.  */
+  if (exp->elts[pc].opcode == OP_VAR_MSYM_VALUE
+      || exp->elts[pc].opcode == OP_VAR_VALUE)
+    {
+      (*pos) += 4;
+
+      value *val;
+      if (exp->elts[pc].opcode == OP_VAR_MSYM_VALUE)
+	{
+	  if (noside == EVAL_AVOID_SIDE_EFFECTS)
+	    return value_zero (to_type, not_lval);
+
+	  val = evaluate_var_msym_value (noside,
+					 exp->elts[pc + 1].objfile,
+					 exp->elts[pc + 2].msymbol);
+	}
+      else
+	val = evaluate_var_value (noside,
+				  exp->elts[pc + 1].block,
+				  exp->elts[pc + 2].symbol);
+
+      if (noside == EVAL_SKIP)
+	return eval_skip_value (exp);
+
+      val = value_cast (to_type, val);
+
+      /* Don't allow e.g. '&(int)var_with_no_debug_info'.  */
+      if (VALUE_LVAL (val) == lval_memory)
+	{
+	  if (value_lazy (val))
+	    value_fetch_lazy (val);
+	  VALUE_LVAL (val) = not_lval;
+	}
+      return val;
+    }
+
+  value *val = evaluate_subexp (to_type, exp, pos, noside);
+  if (noside == EVAL_SKIP)
+    return eval_skip_value (exp);
+  return value_cast (to_type, val);
+}
+
 /* Parse a type expression in the string [P..P+LENGTH).  */
 
 struct type *
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index a22f0ca21e8..fc86225bf67 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -2770,6 +2770,16 @@ init_type (struct objfile *objfile, enum type_code code, int length,
   return type;
 }
 
+/* Allocate a TYPE_CODE_ERROR type structure associated with OBJFILE,
+   to use with variables that have no debug info.  NAME is the type
+   name.  */
+
+static struct type *
+init_nodebug_var_type (struct objfile *objfile, const char *name)
+{
+  return init_type (objfile, TYPE_CODE_ERROR, 0, name);
+}
+
 /* Allocate a TYPE_CODE_INT type structure associated with OBJFILE.
    BIT is the type size in bits.  If UNSIGNED_P is non-zero, set
    the type's TYPE_UNSIGNED flag.  NAME is the type name.  */
@@ -5325,14 +5335,11 @@ objfile_type (struct objfile *objfile)
 			 "<text from jump slot in .got.plt, no debug info>",
 			 objfile_type->nodebug_text_symbol);
   objfile_type->nodebug_data_symbol
-    = init_integer_type (objfile, gdbarch_int_bit (gdbarch), 0,
-			 "<data variable, no debug info>");
+    = init_nodebug_var_type (objfile, "<data variable, no debug info>");
   objfile_type->nodebug_unknown_symbol
-    = init_integer_type (objfile, TARGET_CHAR_BIT, 0,
-			 "<variable (not text or data), no debug info>");
+    = init_nodebug_var_type (objfile, "<variable (not text or data), no debug info>");
   objfile_type->nodebug_tls_symbol
-    = init_integer_type (objfile, gdbarch_int_bit (gdbarch), 0,
-			 "<thread local variable, no debug info>");
+    = init_nodebug_var_type (objfile, "<thread local variable, no debug info>");
 
   /* NOTE: on some targets, addresses and pointers are not necessarily
      the same.
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 5457aa12f59..072423deb79 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,21 @@
 2017-09-04  Pedro Alves  <palves@redhat.com>
 
+	* gdb.asm/asm-source.exp: Add casts to int.
+	* gdb.base/nodebug.c (dataglobal8, dataglobal32_1, dataglobal32_2)
+	(dataglobal64_1, dataglobal64_2): New globals.
+	* gdb.base/nodebug.exp: Test different expressions involving the
+	new globals, with print, whatis and ptype.  Add casts to int.
+	* gdb.base/solib-display.exp: Add casts to int.
+	* gdb.compile/compile-ifunc.exp: Expect warning.  Add cast to int.
+	* gdb.cp/m-static.exp: Add cast to int.
+	* gdb.dwarf2/dw2-skip-prologue.exp: Add cast to int.
+	* gdb.threads/tls-nodebug.exp: Check that gdb errors out printing
+	tls variable with no debug info without a cast.  Test with a cast
+	to int too.
+	* gdb.trace/entry-values.exp: Add casts.
+
+2017-09-04  Pedro Alves  <palves@redhat.com>
+
 	* gdb.base/nodebug.exp: Test that ptype's error about functions
 	with unknown return type includes the function name too.
 
diff --git a/gdb/testsuite/gdb.asm/asm-source.exp b/gdb/testsuite/gdb.asm/asm-source.exp
index e07e5543f20..138609a3c80 100644
--- a/gdb/testsuite/gdb.asm/asm-source.exp
+++ b/gdb/testsuite/gdb.asm/asm-source.exp
@@ -465,14 +465,14 @@ proc test_dis { command var } {
 }
 
 # See if we can look at a global variable, three ways
-gdb_test "print globalvar" ".* = 11" "look at global variable"
+gdb_test "print (int) globalvar" ".* = 11" "look at global variable"
 test_dis "x/i &globalvar" "globalvar"
-test_dis "disassem &globalvar, &globalvar+1" "globalvar"
+test_dis "disassem &globalvar, (int *) &globalvar+1" "globalvar"
 
 # See if we can look at a static variable, three ways
-gdb_test "print staticvar" ".* = 5" "look at static variable"
+gdb_test "print (int) staticvar" ".* = 5" "look at static variable"
 test_dis "x/i &staticvar" "staticvar"
-test_dis "disassem &staticvar, &staticvar+1" "staticvar"
+test_dis "disassem &staticvar, (int *) &staticvar+1" "staticvar"
 
 # See if we can look at a static function
 gdb_test "disassem foostatic" ".*<\\+0>:.*End of assembler dump." \
diff --git a/gdb/testsuite/gdb.base/nodebug.c b/gdb/testsuite/gdb.base/nodebug.c
index 99641e80121..c7bc93991b8 100644
--- a/gdb/testsuite/gdb.base/nodebug.c
+++ b/gdb/testsuite/gdb.base/nodebug.c
@@ -8,6 +8,13 @@ static int datalocal = 4;		/* Should go in local data */
 int bssglobal;				/* Should go in global bss */
 static int bsslocal;			/* Should go in local bss */
 
+/* Non-int-sized global data variables.  */
+uint8_t dataglobal8 = 0xff;
+uint32_t dataglobal32_1 = 0x7fffffff;
+uint32_t dataglobal32_2 = 0x000000ff;
+uint64_t dataglobal64_1 = 0x7fffffffffffffff;
+uint64_t dataglobal64_2 = 0x00000000000000ff;
+
 int
 inner (int x)
 {
diff --git a/gdb/testsuite/gdb.base/nodebug.exp b/gdb/testsuite/gdb.base/nodebug.exp
index da704f10370..2099456dde0 100644
--- a/gdb/testsuite/gdb.base/nodebug.exp
+++ b/gdb/testsuite/gdb.base/nodebug.exp
@@ -152,11 +152,57 @@ if [runto inner] then {
     # we may or may not have debug info for those (depending on
     # whether we have debug info for the C runtime, for example).
     gdb_test_no_output "macro define uint8 unsigned char"
-
-    gdb_test "p dataglobal" "= 3"
-    gdb_test "whatis dataglobal" \
-	"<(data variable|variable), no debug info>|int"
-    gdb_test "ptype dataglobal" "<(data variable|variable), no debug info>|int"
+    gdb_test_no_output "macro define uint32 unsigned int"
+    gdb_test_no_output "macro define uint64 unsigned long long"
+
+    set data_var_type "<data variable, no debug info>"
+    set unk_type_re "has unknown type.*to its declared type"
+    set ptr_math_re "Cannot perform pointer math on incomplete type \"$data_var_type\", try casting to a known type, or void \\*\\."
+    set not_mem_re "Attempt to take address of value not located in memory\\."
+
+    set dataglobal_unk_re "dataglobal.*$unk_type_re"
+
+	 #exp				#fmt #print						#ptype/whatis
+    foreach line {
+	{"dataglobal"			""   $dataglobal_unk_re					" = $data_var_type"}
+	{"(int) dataglobal"		""   "= 3"						" = int"}
+	{"sizeof(dataglobal)"		""   $dataglobal_unk_re					$dataglobal_unk_re}
+	{"sizeof(dataglobal + 1)"	""   $dataglobal_unk_re					$dataglobal_unk_re}
+	{"sizeof((int) dataglobal)"	""   " = $decimal"					" = int"}
+	{"dataglobal + 1"		""   $dataglobal_unk_re					$dataglobal_unk_re}
+	{"&dataglobal"			""   "\\($data_var_type \\*\\) $hex <dataglobal>"	" = $data_var_type \\*"}
+	{"&dataglobal + 1"		""   $ptr_math_re					$ptr_math_re}
+	{"(int *) &dataglobal + 1"	""   " = \\(int \\*\\) $hex <datalocal>"		"int \\*"}
+	{"&(int) dataglobal + 1"	""   $not_mem_re					$not_mem_re}
+	{"&dataglobal, &dataglobal"	""   "\\($data_var_type \\*\\) $hex <dataglobal>"	" = $data_var_type \\*"}
+	{"*dataglobal"			""   $dataglobal_unk_re					$dataglobal_unk_re}
+
+	{"dataglobal8"			"/x" $dataglobal_unk_re					" = $data_var_type"}
+	{"(uint8) dataglobal8"		"/x" " = 0xff"						"unsigned char"}
+
+	{"dataglobal32_1"		"/x" $dataglobal_unk_re					" = $data_var_type"}
+	{"(uint32) dataglobal32_1"	"/x" " = 0x7fffffff"					"unsigned int"}
+	{"dataglobal32_2"		"/x" $dataglobal_unk_re					" = $data_var_type"}
+	{"(uint32) dataglobal32_2"	"/x" " = 0xff"						"unsigned int"}
+
+	{"dataglobal64_1"		"/x" $dataglobal_unk_re					" = $data_var_type"}
+	{"(uint64) dataglobal64_1"	"/x" " = 0x7fffffffffffffff"				"unsigned long long"}
+	{"dataglobal64_2"		"/x" $dataglobal_unk_re					" = $data_var_type"}
+	{"(uint64) dataglobal64_2"	"/x" " = 0xff"						"unsigned long long"}
+    } {
+	set exp [lindex $line 0]
+	# Expand variables.
+	set fmt [subst -nobackslashes [lindex $line 1]]
+	set print [subst  -nobackslashes [lindex $line 2]]
+	set whatis [subst -nobackslashes [lindex $line 3]]
+	if {$fmt == ""} {
+	    gdb_test "p $exp" $print
+	} else {
+	    gdb_test "p $fmt $exp" $print
+	}
+	gdb_test "whatis $exp" $whatis
+	gdb_test "ptype $exp" $whatis
+    }
     
     # The only symbol xcoff puts out for statics is for the TOC entry.
     # Possible, but hairy, for gdb to deal.  Right now it doesn't, it
@@ -164,35 +210,39 @@ if [runto inner] then {
     setup_xfail "rs6000*-*-aix*"
     setup_xfail "powerpc*-*-aix*"
 
-    gdb_test "p datalocal" "= 4"
+    gdb_test "p datalocal" "datalocal.*$unk_type_re"
+    gdb_test "p (int) datalocal" "= 4"
 
     setup_xfail "rs6000*-*-aix*"
     setup_xfail "powerpc*-*-aix*"
 
-    gdb_test "whatis datalocal" "<(data variable|variable), no debug info>"
+    gdb_test "whatis datalocal" "datalocal.*$data_var_type"
 
     setup_xfail "rs6000*-*-aix*"
     setup_xfail "powerpc*-*-aix*"
 
-    gdb_test "ptype datalocal" "<(data variable|variable), no debug info>"
-    gdb_test "p bssglobal" "= 0"
-    gdb_test "whatis bssglobal" "<(data variable|variable), no debug info>|int"
-    gdb_test "ptype bssglobal" "<(data variable|variable), no debug info>|int"
+    gdb_test "ptype datalocal" "datalocal.*$data_var_type"
+
+    gdb_test "p bssglobal" "bssglobal.*$unk_type_re"
+    gdb_test "p (int) bssglobal" "= 0"
+    gdb_test "whatis bssglobal" $data_var_type
+    gdb_test "ptype bssglobal" $data_var_type
 
     setup_xfail "rs6000*-*-aix*"
     setup_xfail "powerpc*-*-aix*"
 
-    gdb_test "p bsslocal" "= 0"
+    gdb_test "p bsslocal" "bsslocal.*$unk_type_re"
+    gdb_test "p (int) bsslocal" "= 0"
 
     setup_xfail "rs6000*-*-aix*"
     setup_xfail "powerpc*-*-aix*"
 
-    gdb_test "whatis bsslocal" "<(data variable|variable), no debug info>"
+    gdb_test "whatis bsslocal" $data_var_type
 
     setup_xfail "rs6000*-*-aix*"
     setup_xfail "powerpc*-*-aix*"
 
-    gdb_test "ptype bsslocal" "<(data variable|variable), no debug info>"
+    gdb_test "ptype bsslocal" $data_var_type
 
     gdb_test "backtrace 10" "#0.*inner.*#1.*middle.*#2.*top.*#3.*main.*" \
 	"backtrace from inner in nodebug.exp"
diff --git a/gdb/testsuite/gdb.base/solib-display.exp b/gdb/testsuite/gdb.base/solib-display.exp
index 1e2685315b5..6df9f260215 100644
--- a/gdb/testsuite/gdb.base/solib-display.exp
+++ b/gdb/testsuite/gdb.base/solib-display.exp
@@ -94,9 +94,9 @@ foreach libsepdebug {NO IN SEP} { with_test_prefix "$libsepdebug" {
       return 0
     }
 
-    gdb_test "display a_global" "1: a_global = 41"
-    gdb_test "display b_global" "2: b_global = 42"
-    gdb_test "display c_global" "3: c_global = 43"
+    gdb_test "display (int) a_global" "1: \\(int\\) a_global = 41"
+    gdb_test "display (int) b_global" "2: \\(int\\) b_global = 42"
+    gdb_test "display (int) c_global" "3: \\(int\\) c_global = 43"
 
     if { [gdb_start_cmd] < 0 } {
 	fail "can't run to main (2)"
@@ -104,9 +104,9 @@ foreach libsepdebug {NO IN SEP} { with_test_prefix "$libsepdebug" {
     }
 
     gdb_test "" [multi_line \
-		     "1: a_global = 41" \
-		     "2: b_global = 42"  \
-		     "3: c_global = 43" \
+		     "1: \\(int\\) a_global = 41" \
+		     "2: \\(int\\) b_global = 42"  \
+		     "3: \\(int\\) c_global = 43" \
 		    ] "after rerun"
 
     # Now rebuild the library without b_global
@@ -132,9 +132,9 @@ foreach libsepdebug {NO IN SEP} { with_test_prefix "$libsepdebug" {
 
 
     gdb_test "" [multi_line \
-		     "1: a_global = 41" \
+		     "1: \\(int\\) a_global = 41" \
 		     "warning: .*b_global.*"  \
-		     "3: c_global = 43" \
+		     "3: \\(int\\) c_global = 43" \
 		    ] "after rerun (2)"
 
     # Now verify that displays which are not in the shared library
diff --git a/gdb/testsuite/gdb.compile/compile-ifunc.exp b/gdb/testsuite/gdb.compile/compile-ifunc.exp
index dc442ffc8ac..b591939d89b 100644
--- a/gdb/testsuite/gdb.compile/compile-ifunc.exp
+++ b/gdb/testsuite/gdb.compile/compile-ifunc.exp
@@ -36,9 +36,10 @@ with_test_prefix "nodebug" {
 	return -1
     }
 
-    gdb_test_no_output "compile code resultvar = gnu_ifunc (10);"
+    gdb_test "compile code resultvar = gnu_ifunc (10);" \
+	"warning: variable has unknown type; assuming int"
 
-    gdb_test "p resultvar" " = 11"
+    gdb_test "p (int) resultvar" " = 11"
 
 }
 
diff --git a/gdb/testsuite/gdb.cp/m-static.exp b/gdb/testsuite/gdb.cp/m-static.exp
index 52eea1ad80e..eeb88e978fb 100644
--- a/gdb/testsuite/gdb.cp/m-static.exp
+++ b/gdb/testsuite/gdb.cp/m-static.exp
@@ -54,8 +54,8 @@ gdb_continue_to_breakpoint "end of constructors"
 
 # simple object, static const int, accessing via 'class::method::variable'
 # Regression test for PR c++/15203 and PR c++/15210
-gdb_test "print 'gnu_obj_1::method()::sintvar'" "\\$\[0-9\]+ = 4" \
-    "simple object, static const int, accessing via 'class::method::variable"
+gdb_test "print (int) 'gnu_obj_1::method()::sintvar'" "\\$\[0-9\]+ = 4" \
+    "simple object, static int, accessing via 'class::method::variable'"
 
 # simple object, static const bool
 gdb_test "print test1.test" "\\$\[0-9\]* = true" "simple object, static const bool"
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-skip-prologue.exp b/gdb/testsuite/gdb.dwarf2/dw2-skip-prologue.exp
index 458809b4b17..6338e6db523 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-skip-prologue.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-skip-prologue.exp
@@ -79,4 +79,4 @@ gdb_continue_to_breakpoint "func"
 # Sanity check GDB has really found 2 locations
 gdb_test {info break $bpnum} "\r\n2\\.1\[ \t\]\[^\n\]*\r\n2\\.2\[ \t\]\[^\n\]*" "2 locations found"
 
-gdb_test "p v" " = 0" "no statement got executed"
+gdb_test "p (int) v" " = 0" "no statement got executed"
diff --git a/gdb/testsuite/gdb.threads/tls-nodebug.exp b/gdb/testsuite/gdb.threads/tls-nodebug.exp
index 8dc9444c4ad..e7187365567 100644
--- a/gdb/testsuite/gdb.threads/tls-nodebug.exp
+++ b/gdb/testsuite/gdb.threads/tls-nodebug.exp
@@ -33,7 +33,10 @@ if ![runto_main] then {
 }
 
 # Formerly: Cannot access memory at address 0x0
-gdb_test "p thread_local" "= 42" "thread local storage"
+gdb_test "p thread_local" "'thread_local' has unknown type; cast it to its declared type" \
+    "thread local storage, unknown type"
+gdb_test "p (int) thread_local" "= 42" \
+    "thread local storage, cast"
 
 # Done!
 #
diff --git a/gdb/testsuite/gdb.trace/entry-values.exp b/gdb/testsuite/gdb.trace/entry-values.exp
index b2650c6d2e5..baf93714ee7 100644
--- a/gdb/testsuite/gdb.trace/entry-values.exp
+++ b/gdb/testsuite/gdb.trace/entry-values.exp
@@ -194,8 +194,8 @@ gdb_test_sequence "bt" "bt (1)" {
 # Update global variables 'global1' and 'global2' and test that the
 # entry values are updated too.
 
-gdb_test_no_output "set var global1=10"
-gdb_test_no_output "set var global2=11"
+gdb_test_no_output "set var *(int *) &global1=10"
+gdb_test_no_output "set var *(int *) &global2=11"
 
 gdb_test_sequence "bt" "bt (2)" {
     "\[\r\n\]#0 .* foo \\(i=[-]?[0-9]+, i@entry=10, j=[-]?[0-9]+, j@entry=11\\)"
@@ -226,7 +226,7 @@ gdb_test "trace foo" "Tracepoint $decimal at .*"
 # argument j.
 
 gdb_trace_setactions "set action for tracepoint 1" "" \
-    "collect i, j, global1, \(\*\(void \*\*\) \(\$$spreg\)\) @ 128" "^$"
+    "collect i, j, (int) global1, \(\*\(void \*\*\) \(\$$spreg\)\) @ 128" "^$"
 
 gdb_test_no_output "tstart"
 
diff --git a/gdb/typeprint.c b/gdb/typeprint.c
index 8e58bf9b5f8..0cc6821cf5a 100644
--- a/gdb/typeprint.c
+++ b/gdb/typeprint.c
@@ -394,6 +394,15 @@ type_print_unknown_return_type (struct ui_file *stream)
   fprintf_filtered (stream, _("<unknown return type>"));
 }
 
+/* See typeprint.h.  */
+
+void
+error_unknown_type (const char *sym_print_name)
+{
+  error (_("'%s' has unknown type; cast it to its declared type"),
+	 sym_print_name);
+}
+
 /* Print type of EXP, or last thing in value history if EXP == NULL.
    show is passed to type_print.  */
 
diff --git a/gdb/typeprint.h b/gdb/typeprint.h
index d4e19e5b881..a458aa4e2f3 100644
--- a/gdb/typeprint.h
+++ b/gdb/typeprint.h
@@ -78,6 +78,11 @@ void c_type_print_args (struct type *, struct ui_file *, int, enum language,
 
 void type_print_unknown_return_type (struct ui_file *stream);
 
+/* Throw an error indicating that the user tried to use a symbol that
+   has unknown type.  SYM_PRINT_NAME is the name of the symbol, to be
+   included in the error message.  */
+extern void error_unknown_type (const char *sym_print_name);
+
 extern void val_print_not_allocated (struct ui_file *stream);
 
 extern void val_print_not_associated (struct ui_file *stream);