From: Mark Wielaard <mark@klomp.org>
To: gcc-rust@gcc.gnu.org
Cc: Mark Wielaard <mark@klomp.org>
Subject: [PATCH] Fix byte char and byte string lexing code
Date: Wed, 22 Sep 2021 00:54:30 +0200 [thread overview]
Message-ID: <20210921225430.166550-1-mark@klomp.org> (raw)
There were two warnings in lexer parse_byte_char and parse_byte_string
code for arches with signed chars:
rust-lex.cc: In member function
‘Rust::TokenPtr Rust::Lexer::parse_byte_char(Location)’:
rust-lex.cc:1564:21: warning: comparison is always false due to limited
range of data type [-Wtype-limits]
1564 | if (byte_char > 127)
| ~~~~~~~~~~^~~~~
rust-lex.cc: In member function
‘Rust::TokenPtr Rust::Lexer::parse_byte_string(Location)’:
rust-lex.cc:1639:27: warning: comparison is always false due to limited
range of data type [-Wtype-limits]
1639 | if (output_char > 127)
| ~~~~~~~~~~~~^~~~~
The fix would be to cast to an unsigned char before the comparison.
But that is actually wrong, and would produce the following errors
parsing a byte char or byte string:
bytecharstring.rs:3:14: error: ‘byte char’ ‘�’ out of range
3 | let _bc = b'\x80';
| ^
bytecharstring.rs:4:14: error: character ‘�’ in byte string out of range
4 | let _bs = b"foo\x80bar";
| ^
Both byte chars and byte strings may contain up to \xFF (255)
characters. It is utf-8 chars or strings that can only
Remove the faulty check and add a new testcase bytecharstring.rs
that checks byte chars and strings do accept > 127 hex char
escapes, but utf-8 chars and strings reject such hex char escapes.
---
https://code.wildebeest.org/git/user/mjw/gccrs/commit/?h=bytecharstring
gcc/rust/lex/rust-lex.cc | 15 ---------------
gcc/testsuite/rust/compile/bytecharstring.rs | 8 ++++++++
2 files changed, 8 insertions(+), 15 deletions(-)
create mode 100644 gcc/testsuite/rust/compile/bytecharstring.rs
diff --git a/gcc/rust/lex/rust-lex.cc b/gcc/rust/lex/rust-lex.cc
index 49b6b6d32a7..b70877be9ff 100644
--- a/gcc/rust/lex/rust-lex.cc
+++ b/gcc/rust/lex/rust-lex.cc
@@ -1559,13 +1559,6 @@ Lexer::parse_byte_char (Location loc)
byte_char = std::get<0> (escape_length_pair);
length += std::get<1> (escape_length_pair);
- if (byte_char > 127)
- {
- rust_error_at (get_current_location (),
- "%<byte char%> %<%c%> out of range", byte_char);
- byte_char = 0;
- }
-
current_char = peek_input ();
if (current_char != '\'')
@@ -1634,14 +1627,6 @@ Lexer::parse_byte_string (Location loc)
else
length += std::get<1> (escape_length_pair);
- if (output_char > 127)
- {
- rust_error_at (get_current_location (),
- "character %<%c%> in byte string out of range",
- output_char);
- output_char = 0;
- }
-
if (output_char != 0)
str += output_char;
diff --git a/gcc/testsuite/rust/compile/bytecharstring.rs b/gcc/testsuite/rust/compile/bytecharstring.rs
new file mode 100644
index 00000000000..9242e2c5a0b
--- /dev/null
+++ b/gcc/testsuite/rust/compile/bytecharstring.rs
@@ -0,0 +1,8 @@
+fn main ()
+{
+ let _bc = b'\x80';
+ let _bs = b"foo\x80bar";
+
+ let _c = '\xef'; // { dg-error "out of range" }
+ let _s = "Foo\xEFBar"; // { dg-error "out of range" }
+}
--
2.32.0
next reply other threads:[~2021-09-21 22:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-21 22:54 Mark Wielaard [this message]
2021-09-22 9:48 ` Thomas Schwinge
2021-09-22 20:37 ` Mark Wielaard
2021-09-23 11:43 ` Philip Herron
2021-09-23 14:10 ` Arthur Cohen
2021-09-23 20:53 ` byte/char string representation (Was: [PATCH] Fix byte char and byte string lexing code) Mark Wielaard
2021-09-24 11:01 ` Philip Herron
2021-09-25 11:53 ` Mark Wielaard
2021-09-30 10:46 ` Philip Herron
2021-10-03 22:04 ` Mark Wielaard
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