Handle TYPE_CODE_PTR when printing Rust types

This changes the Rust type printers to handle TYPE_CODE_PTR.  The
current approach is not ideal, because currently the code can't
distinguish between mut and const, or between pointers and references.
(These are debuginfo deficiencies, for which there are rustc bugs on
file.)

Meanwhile, this at least clears up the case seen in PR rust/23625.

Tested on x86-64 Fedora 28.  The nightly compiler gives the best
results, but I regression-tested with stable and beta as well.

gdb/ChangeLog
2018-11-16  Tom Tromey  <tom@tromey.com>

	PR rust/23625:
	* rust-lang.c (rust_internal_print_type): Handle TYPE_CODE_PTR.

gdb/testsuite/ChangeLog
2018-11-19  Tom Tromey  <tom@tromey.com>

	PR rust/23625:
	* gdb.rust/simple.exp: Add ptype test.  Update expected output.
	* gdb.rust/expr.exp: Update expected output.  Change one test.

3 files changed, 15 insertions, 8 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index e7693a0..daa2839 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2018-11-19  Tom Tromey  <tom@tromey.com>
 
+	PR rust/23625:
+	* gdb.rust/simple.exp: Add ptype test.  Update expected output.
+	* gdb.rust/expr.exp: Update expected output.  Change one test.
+
+2018-11-19  Tom Tromey  <tom@tromey.com>
+
 	* gdb.rust/simple.rs: Don't initialize empty_enum_value.
 
 2018-11-19  Pedro Alves  <palves@redhat.com>
diff --git a/gdb/testsuite/gdb.rust/expr.exp b/gdb/testsuite/gdb.rust/expr.exp
index 22e6b49..ec230c1 100644
--- a/gdb/testsuite/gdb.rust/expr.exp
+++ b/gdb/testsuite/gdb.rust/expr.exp
@@ -134,8 +134,8 @@ gdb_test "ptype \[23usize; 4\]" " = \\\[usize; 4\\\]"
 gdb_test "print \[mut 23usize; 4\]" " = \\\[23, 23, 23, 23\\\]"
 
 # Test lexer corner cases.
-gdb_test "print 0x0 as *const ()" " = \\\(\\\(\\\) \\*\\\) 0x0"
-gdb_test "print 0x0 as fn(i64) -> ()" " = \\\(\\\(\\\) \\\(\\*\\\)\\\(i64\\\)\\\) 0x0"
+gdb_test "print 0x0 as *mut ()" " = \\\(\\*mut \\\(\\\)\\\) 0x0"
+gdb_test "print 0x0 as fn(i64) -> ()" " = \\\(\\*mut fn \\\(i64\\\) -> \\\(\\\)\\\) 0x0"
 gdb_test "print r#" "syntax error in expression, near `#'\\."
 
 gdb_test "printf \"%d %d\\n\", 23+1, 23-1" "24 22"
diff --git a/gdb/testsuite/gdb.rust/simple.exp b/gdb/testsuite/gdb.rust/simple.exp
index 956a6ca..f02ff67 100644
--- a/gdb/testsuite/gdb.rust/simple.exp
+++ b/gdb/testsuite/gdb.rust/simple.exp
@@ -54,6 +54,7 @@ gdb_test "print *&c" " = 0"
 gdb_test "print *(&c as &i32)" " = 0"
 gdb_test "print *(&c as *const i32)" " = 0"
 gdb_test "print *(&c as *mut i32)" " = 0"
+gdb_test "ptype &c as *mut i32" "\\*mut i32"
 
 gdb_test "print/c f\[0\]" " = 104 'h'"
 
@@ -68,8 +69,8 @@ gdb_test "print f" " = \"hi bob\""
 gdb_test "print fslice" " = \"bob\""
 gdb_test "print &f\[3..\]" " = \"bob\""
 
-gdb_test "print g" " = \\(u8 \\(\\*\\)\\\[6\\\]\\) $hex b\"hi bob\""
-gdb_test "ptype g" " = u8 \\(\\*\\)\\\[6\\\]"
+gdb_test "print g" " = \\(\\*mut \\\[u8; 6\\\]\\) $hex b\"hi bob\""
+gdb_test "ptype g" " = \\*mut \\\[u8; 6\\\]"
 
 gdb_test "print v" " = simple::Something::Three"
 gdb_test_sequence "ptype v" "" {
@@ -91,19 +92,19 @@ gdb_test "print slice as &\[i32\]\[0\]" " = 3"
 
 gdb_test_sequence "ptype slice" "" {
     " = struct &\\\[i32\\\] \\{"
-    "  data_ptr: i32 \\*,"
+    "  data_ptr: \\*mut i32,"
     "  length: usize,"
     "\\}"
 }
 gdb_test_sequence "ptype &slice\[..\]" "" {
     " = struct &\\\[i32\\\] \\{"
-    "  data_ptr: i32 \\*,"
+    "  data_ptr: \\*mut i32,"
     "  length: usize,"
     "\\}"
 }
 gdb_test_sequence "ptype &b\[..\]" "" {
     " = struct &\\\[\\*gdb\\*\\\] \\{"
-    "  data_ptr: i32 \\*,"
+    "  data_ptr: \\*mut i32,"
     "  length: usize,"
     "\\}"
 }
@@ -281,7 +282,7 @@ gdb_test "print 23..97.0" "Range expression with different types"
 gdb_test "print (*parametrized.next.val)" \
     " = simple::ParametrizedStruct<i32> {next: simple::ParametrizedEnum<\[a-z:\]*Box<simple::ParametrizedStruct<i32>>>::Empty, value: 1}"
 gdb_test "print parametrized.next.val" \
-    " = \\(simple::ParametrizedStruct<i32> \\*\\) $hex"
+    " = \\(\\*mut simple::ParametrizedStruct<i32>\\) $hex"
 gdb_test "print parametrized" \
     " = simple::ParametrizedStruct<i32> \\{next: simple::ParametrizedEnum<\[a-z:\]*Box<simple::ParametrizedStruct<i32>>>::Val\\{val: $hex\\}, value: 0\\}"