Special case "&str" in Rust parser
Commit Message
"&str" is an important type in Rust -- it's the type of string
literals. However, the compiler puts it in the DWARF in a funny way.
The slice itself is present and named "&str". However, the Rust
parser doesn't look for types with names like this, but instead tries
to construct them from components. In this case it tries to make a
pointer-to-"str" -- but "str" isn't always available, and in any case
that wouldn't yield the best result.
This patch adds a special case for &str.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=22251
---
gdb/rust-parse.c | 10 ++++++++++
gdb/testsuite/gdb.rust/simple.exp | 3 +++
2 files changed, 13 insertions(+)
Comments
Tom Tromey <tom@tromey.com> writes:
> "&str" is an important type in Rust -- it's the type of string
> literals. However, the compiler puts it in the DWARF in a funny way.
> The slice itself is present and named "&str". However, the Rust
> parser doesn't look for types with names like this, but instead tries
> to construct them from components. In this case it tries to make a
> pointer-to-"str" -- but "str" isn't always available, and in any case
> that wouldn't yield the best result.
>
> This patch adds a special case for &str.
>
> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=22251
LGTM.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Thanks,
Andrew
> ---
> gdb/rust-parse.c | 10 ++++++++++
> gdb/testsuite/gdb.rust/simple.exp | 3 +++
> 2 files changed, 13 insertions(+)
>
> diff --git a/gdb/rust-parse.c b/gdb/rust-parse.c
> index 648e48dda40..427169611d3 100644
> --- a/gdb/rust-parse.c
> +++ b/gdb/rust-parse.c
> @@ -1682,6 +1682,16 @@ rust_parser::parse_slice_type ()
> {
> assume ('&');
>
> + /* Handle &str specially. This is an important type in Rust. While
> + the compiler does emit the "&str" type in the DWARF, just "str"
> + itself isn't always available -- but it's handy if this works
> + seamlessly. */
> + if (current_token == IDENT && get_string () == "str")
> + {
> + lex ();
> + return rust_slice_type ("&str", get_type ("u8"), get_type ("usize"));
> + }
> +
> bool is_slice = current_token == '[';
> if (is_slice)
> lex ();
> diff --git a/gdb/testsuite/gdb.rust/simple.exp b/gdb/testsuite/gdb.rust/simple.exp
> index 08ebed3f103..a615b92ec47 100644
> --- a/gdb/testsuite/gdb.rust/simple.exp
> +++ b/gdb/testsuite/gdb.rust/simple.exp
> @@ -68,6 +68,9 @@ gdb_test "print simple::Unit{23}" "'}', '\.\.', or identifier expected"
> gdb_test "print f" " = \"hi bob\""
> gdb_test "print fslice" " = \"bob\""
> gdb_test "print &f\[3..\]" " = \"bob\""
> +gdb_test "whatis f" "type = &str"
> +gdb_test "print *(&f as *mut &str)" " = \"hi bob\"" \
> + "print via cast to &str"
>
> gdb_test "print g" " = \\(\\*mut \\\[u8; 6\\\]\\) $hex b\"hi bob\""
> gdb_test "ptype g" " = \\*mut \\\[u8; 6\\\]"
> --
> 2.39.2
@@ -1682,6 +1682,16 @@ rust_parser::parse_slice_type ()
{
assume ('&');
+ /* Handle &str specially. This is an important type in Rust. While
+ the compiler does emit the "&str" type in the DWARF, just "str"
+ itself isn't always available -- but it's handy if this works
+ seamlessly. */
+ if (current_token == IDENT && get_string () == "str")
+ {
+ lex ();
+ return rust_slice_type ("&str", get_type ("u8"), get_type ("usize"));
+ }
+
bool is_slice = current_token == '[';
if (is_slice)
lex ();
@@ -68,6 +68,9 @@ gdb_test "print simple::Unit{23}" "'}', '\.\.', or identifier expected"
gdb_test "print f" " = \"hi bob\""
gdb_test "print fslice" " = \"bob\""
gdb_test "print &f\[3..\]" " = \"bob\""
+gdb_test "whatis f" "type = &str"
+gdb_test "print *(&f as *mut &str)" " = \"hi bob\"" \
+ "print via cast to &str"
gdb_test "print g" " = \\(\\*mut \\\[u8; 6\\\]\\) $hex b\"hi bob\""
gdb_test "ptype g" " = \\*mut \\\[u8; 6\\\]"