Update string table and use const thread_local

profiling/Cargo.toml

@@ -20,8 +20,8 @@ bumpalo = { version = "3.12", features = ["collections"] }
 cfg-if = { version = "1.0" }
 cpu-time = { version = "1.0" }
 crossbeam-channel = { version = "0.5", default-features = false, features = ["std"] }
-datadog-profiling = { git = "https://github.com/DataDog/libdatadog", rev = "600678b" }
-ddcommon = { git = "https://github.com/DataDog/libdatadog", rev = "600678b" }
+datadog-profiling = { git = "https://github.com/DataDog/libdatadog", rev = "a21056a5fa3c0f54d555a978bd1f3ea9726ef0f8" }
+ddcommon = { git = "https://github.com/DataDog/libdatadog", rev = "a21056a5fa3c0f54d555a978bd1f3ea9726ef0f8" }
 env_logger = { version = "0.10" }
 indexmap = { version = "2.2" }
 lazy_static = { version = "1.4" }

profiling/src/profiling/stalk_walking.rs

@@ -8,7 +8,7 @@ use std::str::Utf8Error;
 /// the fact that there are two cache slots used, and they don't have to be in
 /// sync. However, they usually are, so we simplify.
 #[cfg(php_run_time_cache)]
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct FunctionRunTimeCacheStats {
     hit: usize,
     missed: usize,
@@ -17,16 +17,31 @@ pub struct FunctionRunTimeCacheStats {
 
 #[cfg(php_run_time_cache)]
 impl FunctionRunTimeCacheStats {
+    pub const fn new() -> Self {
+        Self {
+            hit: 0,
+            missed: 0,
+            not_applicable: 0,
+        }
+    }
+
     pub fn hit_rate(&self) -> f64 {
         let denominator = (self.hit + self.missed + self.not_applicable) as f64;
         self.hit as f64 / denominator
     }
 }
 
+#[cfg(php_run_time_cache)]
+impl Default for FunctionRunTimeCacheStats {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 #[cfg(php_run_time_cache)]
 thread_local! {
     static CACHED_STRINGS: RefCell<StringTable> = RefCell::new(StringTable::new());
-    pub static FUNCTION_CACHE_STATS: RefCell<FunctionRunTimeCacheStats> = RefCell::new(Default::default())
+    pub static FUNCTION_CACHE_STATS: RefCell<FunctionRunTimeCacheStats> = const { RefCell::new(FunctionRunTimeCacheStats::new()) };
 }
 
 /// # Safety