From e21d06994f7c750c7fe7448b28408076eb9cf4ce Mon Sep 17 00:00:00 2001
From: Gwilym Inzani <email@gwilym.dev>
Date: Wed, 3 Apr 2024 10:57:34 +0100
Subject: [PATCH] Add some tests which showed issues with the decoder
---
agb-addr2line/src/gwilym_encoding.rs | 77 +++++++++++++++++++++++++++-
agb/src/backtrace.rs | 15 +++---
2 files changed, 83 insertions(+), 9 deletions(-)
diff --git a/agb-addr2line/src/gwilym_encoding.rs b/agb-addr2line/src/gwilym_encoding.rs
index ae006582..fca9896c 100644
--- a/agb-addr2line/src/gwilym_encoding.rs
+++ b/agb-addr2line/src/gwilym_encoding.rs
@@ -61,8 +61,11 @@ impl<'a> Iterator for GwilymDecodeIter<'a> {
};
let value = decode_chunk(chunk);
- if value & (1 << 17) != 0 {
- return Some(self.next().unwrap_or(0) | (value << 16));
+ if value & (1 << 16) != 0 {
+ let upper_bits = value << 16;
+ let lower_bits = self.next().unwrap_or(0) & 0xffff;
+
+ return Some(upper_bits | lower_bits);
}
Some(value | 0x0800_0000)
@@ -89,3 +92,73 @@ fn get_value_for_char(input: u8) -> u32 {
result
})[input as usize] as u32
}
+
+#[cfg(test)]
+mod test {
+ use super::{gwilym_decode, ALPHABET};
+ use std::fmt::Write;
+
+ #[test]
+ fn should_correctly_decode_16s() -> anyhow::Result<()> {
+ assert_eq!(
+ &gwilym_decode("2QI65Q69306Kv1")?.collect::<Vec<_>>(),
+ &[0x0800_16d3, 0x0800_315b, 0x0800_3243, 0x0800_0195]
+ );
+
+ Ok(())
+ }
+
+ fn encode_16(input: u16) -> [u8; 3] {
+ let input = input as usize;
+ [
+ ALPHABET[input >> (16 - 5)],
+ ALPHABET[(input >> (16 - 10)) & 0b11111],
+ ALPHABET[input & 0b111111],
+ ]
+ }
+
+ fn encode_32(input: u32) -> [u8; 6] {
+ let input = input as usize;
+ let output_lower_16 = encode_16(input as u16);
+ let input_upper_16 = input >> 16;
+ [
+ ALPHABET[(input_upper_16 >> (16 - 5)) | (1 << 5)],
+ ALPHABET[(input_upper_16 >> (16 - 10)) & 0b11111],
+ ALPHABET[input_upper_16 & 0b111111],
+ output_lower_16[0],
+ output_lower_16[1],
+ output_lower_16[2],
+ ]
+ }
+
+ #[test]
+ fn should_correctly_decode_16s_and_32s() -> anyhow::Result<()> {
+ let trace: &[u32] = &[
+ 0x0300_2990,
+ 0x0800_3289,
+ 0x0500_2993,
+ 0x3829_2910,
+ 0xffff_ffff,
+ 0x0000_0000,
+ ];
+
+ let mut result = String::new();
+ for &ip in trace {
+ if ip & 0xFFFF_0000 == 0x0800_0000 {
+ let encoded = encode_16(ip as u16);
+ let encoded_s = std::str::from_utf8(&encoded)?;
+ write!(&mut result, "{encoded_s}")?
+ } else {
+ let encoded = encode_32(ip);
+ let encoded_s = std::str::from_utf8(&encoded)?;
+ write!(&mut result, "{encoded_s}")?
+ }
+ }
+
+ write!(&mut result, "v1")?;
+
+ assert_eq!(&gwilym_decode(&result)?.collect::<Vec<_>>(), trace);
+
+ Ok(())
+ }
+}
diff --git a/agb/src/backtrace.rs b/agb/src/backtrace.rs
index 1e3ea241..f65e55e6 100644
--- a/agb/src/backtrace.rs
+++ b/agb/src/backtrace.rs
@@ -120,14 +120,15 @@ mod gwilym_encoding {
pub fn encode_32(input: u32) -> [u8; 6] {
let input = input as usize;
- let output_16 = encode_16(input as u16);
+ let output_lower_16 = encode_16(input as u16);
+ let input_upper_16 = input >> 16;
[
- ALPHABET[(input >> (32 - 5)) | 0b100000],
- ALPHABET[(input >> (32 - 10)) & 0b11111],
- ALPHABET[(input >> (32 - 16)) & 0b111111],
- output_16[0],
- output_16[1],
- output_16[2],
+ ALPHABET[(input_upper_16 >> (16 - 5)) | (1 << 5)],
+ ALPHABET[(input_upper_16 >> (16 - 10)) & 0b11111],
+ ALPHABET[input_upper_16 & 0b111111],
+ output_lower_16[0],
+ output_lower_16[1],
+ output_lower_16[2],
]
}
}