PR 18303, Tolerate malformed input for lookup_symbol-called functions

lookup_symbol is often called with user input.  Consequently, any
function called from lookup_symbol{,_in_language} should attempt to
deal with malformed input gracefully.  After all, malformed user
input is not a programming/API error.

This patch does not attempt to find/correct all instances of this.  It
only fixes locations in the code that trigger test suite failures.

This patch fixes PR breakpoints/18303, "Assertion: -breakpoint-insert
with windows paths of file in non-current directory".

The patch includes three new tests related to this.  One is just
gdb.linespec/ls-errs.exp copied and converted to use C++ instead of C, and
to add a case using a file name containing a Windows-style logical drive
specifier.  The others include an MI test to provide a regression test for
the specific case reported in PR 18303, and a C++ test for proper error
handling of access to a program variable when using a file scope specifier
that refers to a non-existent file.

Tested on x86_64 native Linux.

gdb/ChangeLog
2016-01-28  Keith Seitz  <keiths@redhat.com>

	PR breakpoints/18303
	* cp-namespace.c (cp_lookup_bare_symbol): Change assertion to
	look for "::" instead of simply ":".
	(cp_search_static_and_baseclasses): Return null_block_symbol for
	malformed input.
	Remove assertions.
	* cp-support.c (cp_find_first_component_aux): Do not return
	a prefix length for ':' unless the next character is also ':'.

gdb/testsuite/ChangeLog
2016-01-28  Don Breazeal  <donb@codesourcery.com>

	* gdb.cp/scope-err.cc: New test program.
	* gdb.cp/scope-err.exp: New test script.
	* gdb.linespec/ls-errs.c (myfunction): Expanded to have multiple
	lines and "set breakpoint here" comment.
	* gdb.linespec/ls-errs.exp: Added C++ testing and new test case.
	Fixed some whitespace and format issues.
	* gdb.mi/mi-linespec-err-cp.cc: New test program.
	* gdb.mi/mi-linespec-err-cp.exp: New test script.

10 files changed, 433 insertions, 182 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 35e7eee..63909dd 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,14 @@
+2016-03-15  Keith Seitz  <keiths@redhat.com>
+
+	PR breakpoints/18303
+	* cp-namespace.c (cp_lookup_bare_symbol): Change assertion to
+	look for "::" instead of simply ":".
+	(cp_search_static_and_baseclasses): Return null_block_symbol for
+	malformed input.
+	Remove assertions.
+	* cp-support.c (cp_find_first_component_aux): Do not return
+	a prefix length for ':' unless the next character is also ':'.
+
 2016-03-15  Doug Evans  <dje@google.com>
 
 	* features/aarch64-core.xml (cpsr_flags): New flags type.
diff --git a/gdb/cp-namespace.c b/gdb/cp-namespace.c
index 72002d6..016a42f 100644
--- a/gdb/cp-namespace.c
+++ b/gdb/cp-namespace.c
@@ -170,7 +170,7 @@ cp_lookup_bare_symbol (const struct language_defn *langdef,
      ':' may be in the args of a template spec.  This isn't intended to be
      a complete test, just cheap and documentary.  */
   if (strchr (name, '<') == NULL && strchr (name, '(') == NULL)
-    gdb_assert (strchr (name, ':') == NULL);
+    gdb_assert (strstr (name, "::") == NULL);
 
   sym = lookup_symbol_in_static_block (name, block, domain);
   if (sym.symbol != NULL)
@@ -246,10 +246,9 @@ cp_search_static_and_baseclasses (const char *name,
   struct block_symbol klass_sym;
   struct type *klass_type;
 
-  /* The test here uses <= instead of < because Fortran also uses this,
-     and the module.exp testcase will pass "modmany::" for NAME here.  */
-  gdb_assert (prefix_len + 2 <= strlen (name));
-  gdb_assert (name[prefix_len + 1] == ':');
+  /* Check for malformed input.  */
+  if (prefix_len + 2 > strlen (name) || name[prefix_len + 1] != ':')
+    return null_block_symbol;
 
   /* Find the name of the class and the name of the method, variable, etc.  */
 
diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index df127c4..a71c6ad 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -1037,8 +1037,13 @@ cp_find_first_component_aux (const char *name, int permissive)
 	      return strlen (name);
 	    }
 	case '\0':
-	case ':':
 	  return index;
+	case ':':
+	  /* ':' marks a component iff the next character is also a ':'.
+	     Otherwise it is probably malformed input.  */
+	  if (name[index + 1] == ':')
+	    return index;
+	  break;
 	case 'o':
 	  /* Operator names can screw up the recursion.  */
 	  if (operator_possible
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 25154c6..aa5422b 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,14 @@
+2016-03-15  Don Breazeal  <donb@codesourcery.com>
+
+	* gdb.cp/scope-err.cc: New test program.
+	* gdb.cp/scope-err.exp: New test script.
+	* gdb.linespec/ls-errs.c (myfunction): Expanded to have multiple
+	lines and "set breakpoint here" comment.
+	* gdb.linespec/ls-errs.exp: Added C++ testing and new test case.
+	Fixed some whitespace and format issues.
+	* gdb.mi/mi-linespec-err-cp.cc: New test program.
+	* gdb.mi/mi-linespec-err-cp.exp: New test script.
+
 2016-03-15  Doug Evans  <dje@google.com>
 
 	* gdb.xml/extra-regs.xml: Add enum, mixed_flags values.
diff --git a/gdb/testsuite/gdb.cp/scope-err.cc b/gdb/testsuite/gdb.cp/scope-err.cc
new file mode 100644
index 0000000..19c92d8
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/scope-err.cc
@@ -0,0 +1,35 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int
+myfunction (int aa)
+{
+  int i;
+
+  i = aa + 42;
+  return i;    /* set breakpoint here */
+}
+
+int
+main (void)
+{
+  int a;
+
+  a = myfunction (a);
+
+  return a;
+}
diff --git a/gdb/testsuite/gdb.cp/scope-err.exp b/gdb/testsuite/gdb.cp/scope-err.exp
new file mode 100644
index 0000000..b197829
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/scope-err.exp
@@ -0,0 +1,49 @@
+# Copyright 2012-2016 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Tests for linespec errors with C++.
+# Derived from gdb.linespec/ls-errs.exp.
+
+if {[skip_cplus_tests]} {
+    continue
+}
+
+standard_testfile .cc
+set exefile $testfile
+
+if {[prepare_for_testing $testfile $exefile $srcfile {debug c++}]} {
+    return -1
+}
+
+if {![runto_main]} {
+    fail "Can't run to main"
+    return 0
+}
+
+# Run to a location in the file.
+set bp_location [gdb_get_line_number "set breakpoint here"]
+
+gdb_test "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line $bp_location\\." \
+    "breakpoint line number in file"
+
+gdb_continue_to_breakpoint "$bp_location"
+
+# Try to access a variable using scope that is a non-existent filename
+# with a Windows-style logical drive in the name.
+set nonexistent_file C:/does/not/exist.cc
+gdb_test "print '$nonexistent_file'::var" \
+	 ".*No symbol \"$nonexistent_file\" in current context.*" \
+	 "print var from \"$nonexistent_file\""
diff --git a/gdb/testsuite/gdb.linespec/ls-errs.c b/gdb/testsuite/gdb.linespec/ls-errs.c
index ca41342..a3a43db 100644
--- a/gdb/testsuite/gdb.linespec/ls-errs.c
+++ b/gdb/testsuite/gdb.linespec/ls-errs.c
@@ -15,14 +15,21 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-int myfunction (void) { return 0; }
+int
+myfunction (int aa)
+{
+  int i;
+
+  i = aa + 42;
+  return i;    /* set breakpoint here */
+}
 
 int
 main (void)
-{  
+{
   int a;
 
-  a = myfunction ();
+  a = myfunction (a);
 
  here:
   return a;
diff --git a/gdb/testsuite/gdb.linespec/ls-errs.exp b/gdb/testsuite/gdb.linespec/ls-errs.exp
index 16d4574..bc4ca26 100644
--- a/gdb/testsuite/gdb.linespec/ls-errs.exp
+++ b/gdb/testsuite/gdb.linespec/ls-errs.exp
@@ -13,209 +13,249 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Tests for linespec error conditions
+# Tests for linespec errors with C and C++.
 
-standard_testfile
-set exefile $testfile
+# The test proper.  LANG is either C or C++.
 
-if {[prepare_for_testing $testfile $exefile $srcfile \
-	 {debug nowarnings}]} {
-    return -1
-}
+proc do_test {lang} {
+    global testfile srcfile error_messages compiler_info
 
-# Turn off the pending breakpoint queries.
-gdb_test_no_output "set breakpoint pending off"
+    standard_testfile
+    set exefile $testfile
+    if [info exists compiler_info] {
+	# Unsetting compiler_info allows us to switch compilers
+	# used by prepare_for_testing.
+        unset compiler_info
+    }
+    set options {debug}
+
+    if {$lang == "C++"} {
+	if {[skip_cplus_tests]} {
+	    return 0
+	}
+	# Build ".c" source file with g++.
+	lappend options "c++"
+    }
 
-# Turn off completion limiting
-gdb_test_no_output "set max-completions unlimited"
+    if {[prepare_for_testing $testfile $exefile $srcfile $options]} {
+	return -1
+    }
 
-# We intentionally do not use gdb_breakpoint for these tests.
+    # Turn off the pending breakpoint queries.
+    gdb_test_no_output "set breakpoint pending off"
 
-# Break at 'linespec' and expect the message in ::error_messages indexed by
-# msg_id with the associated args.
-proc test_break {linespec msg_id args} {
-    global error_messages
+    # Turn off completion limiting
+    gdb_test_no_output "set max-completions unlimited"
 
-    gdb_test "break $linespec" [string_to_regexp \
-				[eval format \$error_messages($msg_id) $args]]
-}
+    if {![runto_main]} {
+	fail "Can't run to main"
+	return 0
+    }
 
-# Common error message format strings.
-array set error_messages {
-    invalid_file "No source file named %s."
-    invalid_function "Function \"%s\" not defined."
-    invalid_var_or_func "Undefined convenience variable or function \"%s\" not defined."
-    invalid_function_f "Function \"%s\" not defined in \"%s\"."
-    invalid_var_or_func_f \
-	"Undefined convenience variable or function \"%s\" not defined in \"%s\"."
-    invalid_label "No label \"%s\" defined in function \"%s\"."
-    invalid_parm "invalid linespec argument, \"%s\""
-    invalid_offset "No line %d in the current file."
-    invalid_offset_f "No line %d in file \"%s\"."
-    malformed_line_offset "malformed line offset: \"%s\""
-    source_incomplete \
-	"Source filename requires function, label, or line offset."
-    unexpected "malformed linespec error: unexpected %s"
-    unexpected_opt "malformed linespec error: unexpected %s, \"%s\""
-    unmatched_quote "unmatched quote"
-    garbage "Garbage '%s' at end of command"
-}
+    # Run to a location in the file.
+    set bp_location [gdb_get_line_number "set breakpoint here"]
+
+    gdb_test "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line $bp_location\\." \
+    "breakpoint line number in file"
+
+    gdb_continue_to_breakpoint "$bp_location"
+
+    # Common error message format strings.
+    array set error_messages {
+	invalid_file "No source file named %s."
+	invalid_function "Function \"%s\" not defined."
+	invalid_var_or_func
+	    "Undefined convenience variable or function \"%s\" not defined."
+	invalid_function_f "Function \"%s\" not defined in \"%s\"."
+	invalid_var_or_func_f \
+	    "Undefined convenience variable or function \"%s\" not defined in \"%s\"."
+	invalid_label "No label \"%s\" defined in function \"%s\"."
+	invalid_parm "invalid linespec argument, \"%s\""
+	invalid_offset "No line %d in the current file."
+	invalid_offset_f "No line %d in file \"%s\"."
+	malformed_line_offset "malformed line offset: \"%s\""
+	source_incomplete \
+	    "Source filename requires function, label, or line offset."
+	unexpected "malformed linespec error: unexpected %s"
+	unexpected_opt "malformed linespec error: unexpected %s, \"%s\""
+	unmatched_quote "unmatched quote"
+	garbage "Garbage '%s' at end of command"
+    }
 
-# Some commonly used whitespace tests around ':'.
-set spaces [list ":" ": " " :" " : " "\t:  " "  :\t" "\t:\t" " \t:\t " \
-		"\t  \t:\t  \t  \t"]
+    # We intentionally do not use gdb_breakpoint for these tests.
 
-# A list of invalid offsets.
-set invalid_offsets [list -100 +500 1000]
+    # Break at 'linespec' and expect the message in ::error_messages
+    # indexed by msg_id with the associated args.
+    proc test_break {linespec msg_id args} {
+	global error_messages
 
-# Try some simple, invalid linespecs involving spaces.
-foreach x $spaces {
-    test_break $x unexpected "colon"
-}
+	gdb_test "break $linespec" [string_to_regexp \
+				    [eval format \$error_messages($msg_id) \
+				     $args]]
+    }
 
-# Test invalid filespecs starting with offset.  This is done
-# first so that default offsets are tested.
-foreach x $invalid_offsets {
-    set offset $x
+    # Some commonly used whitespace tests around ':'.
+    set spaces [list ":" ": " " :" " : " "\t:  " "  :\t" "\t:\t" \
+		     " \t:\t " "\t  \t:\t  \t  \t"]
 
-    # Relative offsets are relative to line 16.  Adjust
-    # expected offset from error message accordingly.
-    if {[string index $x 0] == "+" ||
-	[string index $x 0] == "-"} {
-	incr offset 16
-    }
-    test_break $x invalid_offset $offset
-    test_break "-line $x" invalid_offset $offset
-}
+    # A list of invalid offsets.
+    set invalid_offsets [list -100 +500 1000]
 
-# Test offsets with trailing tokens w/ and w/o spaces.
-foreach x $spaces {
-    test_break "3$x" unexpected "colon"
-    test_break "+10$x" unexpected "colon"
-    test_break "-10$x" unexpected "colon"
-}
+    # Try some simple, invalid linespecs involving spaces.
+    foreach x $spaces {
+	test_break $x unexpected "colon"
+    }
 
-foreach x {1 +1 +100 -10} {
-    test_break "3 $x" unexpected_opt "number" $x
-    test_break "-line 3 $x" garbage $x
-    test_break "+10 $x" unexpected_opt "number" $x
-    test_break "-line +10 $x" garbage $x
-    test_break "-10 $x" unexpected_opt "number" $x
-    test_break "-line -10 $x" garbage $x
-}
+    # Test invalid filespecs starting with offset.  This is done
+    # first so that default offsets are tested.
+    foreach x $invalid_offsets {
+	set offset $x
+
+	# Relative offsets are relative to line 16.  Adjust
+	# expected offset from error message accordingly.
+	if {[string index $x 0] == "+" || [string index $x 0] == "-"} {
+	    incr offset 24
+	}
+	test_break $x invalid_offset $offset
+	test_break "-line $x" invalid_offset $offset
+    }
 
-foreach x {3 +10 -10} {
-    test_break "$x foo" unexpected_opt "string" "foo"
-    test_break "-line $x foo" garbage "foo"
-}
+    # Test offsets with trailing tokens w/ and w/o spaces.
+    foreach x $spaces {
+	test_break "3$x" unexpected "colon"
+	test_break "+10$x" unexpected "colon"
+	test_break "-10$x" unexpected "colon"
+    }
 
-# Test invalid linespecs starting with filename.
-foreach x [list "this_file_doesn't_exist.c" \
-	       "this file has spaces.c" \
-	       "\"file::colons.c\"" \
-	       "'file::colons.c'" \
-	       "\"this \"file\" has quotes.c\"" \
-	       "'this \"file\" has quotes.c'" \
-	       "'this 'file' has quotes.c'" \
-	       "\"this 'file' has quotes.c\"" \
-	       "\"spaces: and :colons.c\"" \
-	       "'more: :spaces: :and  colons::.c'"] {
-    # Remove any quoting from FILENAME for the error message.
-    test_break "$x:3" invalid_file [string trim $x \"']
-}
-foreach x [list "this_file_doesn't_exist.c" \
-	       "file::colons.c" \
-	       "'file::colons.c'"] {
-    test_break "-source $x -line 3" \
-	invalid_file [string trim $x \"']
-}
+    foreach x {1 +1 +100 -10} {
+	test_break "3 $x" unexpected_opt "number" $x
+	test_break "-line 3 $x" garbage $x
+	test_break "+10 $x" unexpected_opt "number" $x
+	test_break "-line +10 $x" garbage $x
+	test_break "-10 $x" unexpected_opt "number" $x
+	test_break "-line -10 $x" garbage $x
+    }
 
-# Test that option lexing stops at whitespace boundaries
-test_break "-source this file has spaces.c -line 3" \
-    invalid_file "this"
+    foreach x {3 +10 -10} {
+	test_break "$x foo" unexpected_opt "string" "foo"
+	test_break "-line $x foo" garbage "foo"
+    }
 
-test_break "-function function whitespace" \
-    invalid_function "function"
+    # Test invalid linespecs starting with filename.
+    # It's OK to use the ".c" extension for the C++ test
+    # since the extension doesn't affect GDB's lookup.
+    set invalid_files [list "this_file_doesn't_exist.c" \
+			    "this file has spaces.c" \
+			    "\"file::colons.c\"" \
+			    "'file::colons.c'" \
+			    "\"this \"file\" has quotes.c\"" \
+			    "'this \"file\" has quotes.c'" \
+			    "'this 'file' has quotes.c'" \
+			    "\"this 'file' has quotes.c\"" \
+			    "\"spaces: and :colons.c\"" \
+			    "'more: :spaces: :and  colons::.c'" \
+			    "C:/nonexist-with-windrive.c"]
+
+    foreach x $invalid_files {
+	# Remove any quoting from FILENAME for the error message.
+	test_break "$x:3" invalid_file [string trim $x \"']
+    }
+    foreach x [list "this_file_doesn't_exist.c" \
+		    "file::colons.c" \
+		    "'file::colons.c'"] {
+	test_break "-source $x -line 3" invalid_file [string trim $x \"']
+    }
 
-test_break "-source $srcfile -function function whitespace" \
-    invalid_function_f "function" $srcfile
+    # Test that option lexing stops at whitespace boundaries
+    test_break "-source this file has spaces.c -line 3" invalid_file "this"
+    test_break "-function function whitespace" invalid_function "function"
+    test_break "-source $srcfile -function function whitespace" \
+	       invalid_function_f "function" $srcfile
 
-test_break "-function main -label label whitespace" \
-    invalid_label "label" "main"
+    test_break "-function main -label label whitespace" \
+	       invalid_label "label" "main"
 
-# Test unmatched quotes.
-foreach x {"\"src-file.c'" "'src-file.c"} {
-    test_break "$x:3" unmatched_quote
-}
+    # Test unmatched quotes.
+    foreach x {"\"src-file.c'" "'src-file.c"} {
+	test_break "$x:3" unmatched_quote
+    }
 
-test_break $srcfile invalid_function $srcfile
-foreach x {"foo" " foo" " foo "} {
-    # Trim any leading/trailing whitespace for error messages.
-    test_break "$srcfile:$x" invalid_function_f [string trim $x] $srcfile
-    test_break "-source $srcfile -function $x" \
-	invalid_function_f [string trim $x] $srcfile
-    test_break "$srcfile:main:$x" invalid_label [string trim $x] "main"
-    test_break "-source $srcfile -function main -label $x" \
-	invalid_label [string trim $x] "main"
-}
+    test_break $srcfile invalid_function $srcfile
+    foreach x {"foo" " foo" " foo "} {
+	# Trim any leading/trailing whitespace for error messages.
+	test_break "$srcfile:$x" invalid_function_f [string trim $x] $srcfile
+	test_break "-source $srcfile -function $x" \
+		   invalid_function_f [string trim $x] $srcfile
+	test_break "$srcfile:main:$x" invalid_label [string trim $x] "main"
+	test_break "-source $srcfile -function main -label $x" \
+		   invalid_label [string trim $x] "main"
+    }
 
-foreach x $spaces {
-    test_break "$srcfile$x" unexpected "end of input"
-    test_break "$srcfile:main$x" unexpected "end of input"
-}
+    foreach x $spaces {
+	test_break "$srcfile$x" unexpected "end of input"
+	test_break "$srcfile:main$x" unexpected "end of input"
+    }
 
-test_break "${srcfile}::" invalid_function "${srcfile}::"
-test_break "$srcfile:3 1" unexpected_opt "number" "1"
-test_break "-source $srcfile -line 3 1" garbage "1"
-test_break "$srcfile:3 +100" unexpected_opt "number" "+100"
-test_break "-source $srcfile -line 3 +100" garbage "+100"
-test_break "$srcfile:3 -100" unexpected_opt "number" "-100"
-test_break "$srcfile:3 foo" unexpected_opt "string" "foo"
-test_break "-source $srcfile -line 3 foo" garbage "foo"
-
-foreach x $invalid_offsets {
-    test_break "$srcfile:$x" invalid_offset_f $x $srcfile
-    test_break "\"$srcfile:$x\"" invalid_offset_f $x $srcfile
-    test_break "'$srcfile:$x'" invalid_offset_f $x $srcfile
-    test_break "-source $srcfile -line $x" invalid_offset_f $x $srcfile
-}
-test_break "-source $srcfile -line -x" malformed_line_offset "-x"
+    test_break "${srcfile}::" invalid_function "${srcfile}::"
+    test_break "$srcfile:3 1" unexpected_opt "number" "1"
+    test_break "-source $srcfile -line 3 1" garbage "1"
+    test_break "$srcfile:3 +100" unexpected_opt "number" "+100"
+    test_break "-source $srcfile -line 3 +100" garbage "+100"
+    test_break "$srcfile:3 -100" unexpected_opt "number" "-100"
+    test_break "$srcfile:3 foo" unexpected_opt "string" "foo"
+    test_break "-source $srcfile -line 3 foo" garbage "foo"
+
+    foreach x $invalid_offsets {
+	test_break "$srcfile:$x" invalid_offset_f $x $srcfile
+	test_break "\"$srcfile:$x\"" invalid_offset_f $x $srcfile
+	test_break "'$srcfile:$x'" invalid_offset_f $x $srcfile
+	test_break "-source $srcfile -line $x" invalid_offset_f $x $srcfile
+    }
+    test_break "-source $srcfile -line -x" malformed_line_offset "-x"
 
-# Test invalid filespecs starting with function.
-foreach x {"foobar" "foo::bar" "foo.bar" "foo ." "foo bar" "foo 1" \
+    # Test invalid filespecs starting with function.
+    foreach x {"foobar" "foo::bar" "foo.bar" "foo ." "foo bar" "foo 1" \
 	       "foo 0" "foo +10" "foo -10" "foo +100" "foo -100"} {
-    test_break $x invalid_function $x
-    test_break "-function \"$x\"" invalid_function $x
-}
+	test_break $x invalid_function $x
+	test_break "-function \"$x\"" invalid_function $x
+    }
 
-foreach x $spaces {
-    test_break "main${x}there" invalid_label "there" "main"
-    if {[test_compiler_info {clang-*-*}]} {  setup_xfail clang/14500 *-*-* }
-    test_break "main:here${x}" unexpected "end of input"
-}
+    foreach x $spaces {
+	test_break "main${x}there" invalid_label "there" "main"
+	if {[test_compiler_info {clang-*-*}]} {
+	    setup_xfail clang/14500 *-*-*
+	}
+	test_break "main:here${x}" unexpected "end of input"
+    }
 
-foreach x {"3" "+100" "-100" "foo"} {
-    test_break "main 3" invalid_function "main 3"
-    test_break "-function \"main $x\"" invalid_function "main $x"
-    test_break "main:here $x" invalid_label "here $x" "main"
-    test_break "-function main -label \"here $x\"" \
-	invalid_label "here $x" "main"
-}
+    foreach x {"3" "+100" "-100" "foo"} {
+	test_break "main 3" invalid_function "main 3"
+	test_break "-function \"main $x\"" invalid_function "main $x"
+	test_break "main:here $x" invalid_label "here $x" "main"
+	test_break "-function main -label \"here $x\"" \
+		   invalid_label "here $x" "main"
+    }
 
-foreach x {"if" "task" "thread"} {
-    test_break $x invalid_function $x
-}
+    foreach x {"if" "task" "thread"} {
+	test_break $x invalid_function $x
+    }
 
-test_break "'main.c'flubber" unexpected_opt "string" "flubber"
-test_break "'main.c',21" invalid_function "main.c"
-test_break "'main.c' " invalid_function "main.c"
-test_break "'main.c'3" unexpected_opt "number" "3"
-test_break "'main.c'+3" unexpected_opt "number" "+3"
+    test_break "'main.c'flubber" unexpected_opt "string" "flubber"
+    test_break "'main.c',21" invalid_function "main.c"
+    test_break "'main.c' " invalid_function "main.c"
+    test_break "'main.c'3" unexpected_opt "number" "3"
+    test_break "'main.c'+3" unexpected_opt "number" "+3"
 
-# Test undefined convenience variables.
-set x {$zippo}
-test_break $x invalid_var_or_func $x
-test_break "$srcfile:$x" invalid_var_or_func_f $x $srcfile
+    # Test undefined convenience variables.
+    set x {$zippo}
+    test_break $x invalid_var_or_func $x
+    test_break "$srcfile:$x" invalid_var_or_func_f $x $srcfile
 
-# Explicit linespec-specific tests
-test_break "-source $srcfile" source_incomplete
+    # Explicit linespec-specific tests
+    test_break "-source $srcfile" source_incomplete
+}
+
+foreach_with_prefix lang {"C" "C++"} {
+    do_test ${lang}
+}
diff --git a/gdb/testsuite/gdb.mi/mi-linespec-err-cp.cc b/gdb/testsuite/gdb.mi/mi-linespec-err-cp.cc
new file mode 100644
index 0000000..19c92d8
--- /dev/null
+++ b/gdb/testsuite/gdb.mi/mi-linespec-err-cp.cc
@@ -0,0 +1,35 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int
+myfunction (int aa)
+{
+  int i;
+
+  i = aa + 42;
+  return i;    /* set breakpoint here */
+}
+
+int
+main (void)
+{
+  int a;
+
+  a = myfunction (a);
+
+  return a;
+}
diff --git a/gdb/testsuite/gdb.mi/mi-linespec-err-cp.exp b/gdb/testsuite/gdb.mi/mi-linespec-err-cp.exp
new file mode 100644
index 0000000..3435508
--- /dev/null
+++ b/gdb/testsuite/gdb.mi/mi-linespec-err-cp.exp
@@ -0,0 +1,59 @@
+# Copyright 2016 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Regression test for PR breakpoints/18303.  Tests that the correct
+# errors is generated when setting a breakpoint in a non-existent
+# file with a Windows-style logical drive names and C++.
+
+if {[skip_cplus_tests]} {
+    continue
+}
+
+load_lib mi-support.exp
+set MIFLAGS "-i=mi"
+
+standard_testfile .cc
+set exefile $testfile
+
+if {[prepare_for_testing $testfile $exefile $srcfile {debug c++}]} {
+    return -1
+}
+
+gdb_exit
+if {[mi_gdb_start]} {
+    continue
+}
+
+# Turn off the pending breakpoint queries.
+mi_gdb_test "-interpreter-exec console \"set breakpoint pending off\"" \
+  {=cmd-param-changed,param=\"breakpoint pending\",.*\^done} \
+  "-interpreter-exec console \"set breakpoint pending off\""
+
+mi_run_to_main
+
+# Run to a location in the file.
+set bp_location [gdb_get_line_number "set breakpoint here"]
+
+mi_gdb_test "-break-insert ${srcfile}:${bp_location}" \
+    {\^done,bkpt=.number="2",type="breakpoint".*\}} "set breakpoint"
+
+mi_execute_to "exec-continue" "breakpoint-hit" "myfunction" ".*" ".*" "24" \
+    { "" "disp=\"keep\"" } "breakpoint hit"
+
+# Set a breakpoint in a C++ source file whose name contains a
+# Windows-style logical drive.
+mi_gdb_test \
+    "-break-insert -f \"c:/uu.cpp:13\"" \
+    ".*No source file named c:/uu.cpp.*"