Fix gdb.base/completion.exp with --target_board=dwarf4-gdb-index

This is the same patch as posted at
<https://sourceware.org/ml/gdb-patches/2017-02/msg00644.html>, with
the test at
<https://sourceware.org/ml/gdb-patches/2017-02/msg00687.html> squashed
in.

This patch fixes:

 -FAIL: gdb.base/completion.exp: tab complete break break.c:ma (timeout)
 -FAIL: gdb.base/completion.exp: complete break break.c:ma
 +PASS: gdb.base/completion.exp: tab complete break break.c:ma
 +PASS: gdb.base/completion.exp: delete breakpoint for tab complete break break.c:ma
 +PASS: gdb.base/completion.exp: complete break break.c:ma

When run with --target_board=dwarf4-gdb-index.

The issue here is that make_file_symbol_completion_list_1, used when
completing a symbol restricted to a given source file, uses
lookup_symtab to look up the symtab with the given name, and search
for matching symbols inside.  This assumes that there's only one
symtab for the given source file.  This is an incorrect assumption
with (for example) -fdebug-types-section, where we'll have an extra
extra symtab containing the types.  lookup_symtab finds that symtab,
and inside that symtab there are no functions...

gdb/ChangeLog:
2017-07-14  Pedro Alves  <palves@redhat.com>

	* symtab.c (make_file_symbol_completion_list_1): Iterate over
	symtabs matching all symtabs with SRCFILE as file name instead of
	only considering the first hit, with lookup_symtab.

gdb/testsuite/ChangeLog:
2017-07-14  Pedro Alves  <palves@redhat.com>

	* gdb.linespec/base/one/thefile.cc (z1): New function.
	* gdb.linespec/base/two/thefile.cc (z2): New function.
	* gdb.linespec/linespec.exp: Add tests.

3 files changed, 100 insertions, 3 deletions

diff --git a/gdb/testsuite/gdb.linespec/base/one/thefile.cc b/gdb/testsuite/gdb.linespec/base/one/thefile.cc
index 0417b7a7a4..34bc54704c 100644
--- a/gdb/testsuite/gdb.linespec/base/one/thefile.cc
+++ b/gdb/testsuite/gdb.linespec/base/one/thefile.cc
@@ -23,3 +23,8 @@ int NameSpace::overload(int x)
 {
   return x + 23;
 }
+
+int z1 ()
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.linespec/base/two/thefile.cc b/gdb/testsuite/gdb.linespec/base/two/thefile.cc
index 88188a5e0d..264ae97869 100644
--- a/gdb/testsuite/gdb.linespec/base/two/thefile.cc
+++ b/gdb/testsuite/gdb.linespec/base/two/thefile.cc
@@ -24,3 +24,8 @@ int NameSpace::overload(double x)
 {
   return (int) x - 23;
 }
+
+int z2 ()
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.linespec/linespec.exp b/gdb/testsuite/gdb.linespec/linespec.exp
index ccb73c801b..b30ac10836 100644
--- a/gdb/testsuite/gdb.linespec/linespec.exp
+++ b/gdb/testsuite/gdb.linespec/linespec.exp
@@ -43,6 +43,9 @@ if {$l1 != $l2} {
     error "somebody incompatibly modified the source files needed by linespec.exp"
 }
 
+gdb_test_no_output "set breakpoint pending off" \
+    "disable pending breakpoints for linespec tests"
+
 # Copying files to a remote host loses the directory prefix during
 # compilation.
 if { [is_remote host] } {
@@ -55,6 +58,93 @@ if { [is_remote host] } {
     gdb_test "clear one/thefile.cc:$l1" \
         "Deleted breakpoint $decimal *" \
         "clear breakpoint using dir/file:line"
+
+    if { [readline_is_used] } {
+	# There are functions named 'twodup' in both source files.
+	# Both should be found if we restrict the linespec to the
+	# ambiguous "thefile.cc" source filename.  Check both
+	# completion and setting the breakpoint.
+	set tst "complete unique function name in two source files"
+	send_gdb "break thefile.cc:t\t"
+	gdb_test_multiple "" $tst {
+	    -re "break thefile.cc:twodup\\(\\) " {
+		pass $tst
+
+		send_gdb "\n"
+		gdb_test "" \
+		    "Breakpoint $decimal at $hex: thefile.cc:twodup\\(\\). \[(\]2 locations\[)\]" \
+		    "set break at unique function name in two source files"
+	    }
+	}
+
+	# Check both completing and setting a breakpoint on a linespec
+	# with a source component, where there's more than one source
+	# file with the same basename.  We should find the functions
+	# in all matching sources -- one/thefile.cc and
+	# two/thefile.cc.  The "one" file has "z1()", while the "two"
+	# file has "z2()".
+	set tst "complete non-unique function name in two source files"
+	send_gdb "break thefile.cc:z\t"
+	gdb_test_multiple "" $tst {
+	    -re "break thefile.cc:z\\\x07" {
+		send_gdb "\t"
+		gdb_test_multiple "" $tst {
+		    -re "\r\nz1\\(\\)\[ \t\]+z2\\(\\)\[ \t\]+\r\n$gdb_prompt " {
+			pass $tst
+
+			send_gdb "\n"
+			gdb_test "" \
+			    "Function \"z\" not defined in \"thefile.cc\"." \
+			    "set break at non-unique function name in two source files"
+		    }
+		}
+	    }
+	}
+
+	# Now check that disambiguating the source path makes GDB only
+	# match the symbols in that file.  "z" should now have a
+	# unique completion to "z1()", and setting the breakpoint
+	# should find only one location.
+	set tst "complete unique function name in disambiguated source file"
+	send_gdb "break one/thefile.cc:z\t"
+	gdb_test_multiple "" $tst {
+	    -re "break one/thefile.cc:z1\\(\\) " {
+		pass $tst
+
+		send_gdb "\n"
+		gdb_test "" \
+		    "Breakpoint $decimal at $hex: file .*thefile.cc, line \[^\r\n\]*" \
+		    "set break at unique function name in disambiguated source file"
+		}
+	}
+
+	# Check that using a non-existing source path does not confuse
+	# GDB.  It should not match any symbol.
+	set dir_file "one/thefile.cc"
+	set non_existing "/some/non-existing/absolute/path/prefix/$dir_file"
+	set non_existing_re [string_to_regexp $non_existing]
+
+	set tst "complete functions in non-existing absolute path"
+	send_gdb "break $non_existing:\t"
+	gdb_test_multiple "" $tst {
+	    -re "break $non_existing_re:\\\x07" {
+		send_gdb "\t\t"
+		gdb_test_multiple "" $tst {
+		    -re "^\\\x07\\\x07" {
+			pass $tst
+
+			# There's a function called 'twodup' in each
+			# of the thefile.cc files.  Make sure none is
+			# picked.
+			send_gdb "twodup\n"
+			gdb_test "" \
+			    "No source file named $non_existing_re." \
+			    "set break in function in non-existing absolute path"
+		    }
+		}
+	    }
+	}
+    }
 }
 
 gdb_test "break thefile.cc:$l1" \
@@ -73,9 +163,6 @@ gdb_test "break dupname:label" \
 # not the locations.
 gdb_test "complete condition " "condition $decimal\r\ncondition $decimal\r\ncondition $decimal"
 
-gdb_test_no_output "set breakpoint pending off" \
-    "disable pending breakpoints for linespec tests"
-
 # This is PR breakpoints/12856.
 gdb_test "break lspec.cc:nosuchfunction" \
     "Function \"nosuchfunction\" not defined in \"lspec.cc\"." \