fix: stop filtering out zero sized symbol

Author: GuillaumeLagrange

src/executor/wall_time/perf/perf_map.rs

@@ -79,7 +79,30 @@ impl ModuleSymbols {
             }));
         }
 
-        symbols.retain(|symbol| symbol.addr > 0 && symbol.size > 0);
+        // Update zero-sized symbols to cover the range until the next symbol
+        // This is what perf does
+        // https://github.com/torvalds/linux/blob/e538109ac71d801d26776af5f3c54f548296c29c/tools/perf/util/symbol.c#L256
+        // A common source for these is inline assembly functions.
+        symbols.sort_by_key(|symbol| symbol.addr);
+        for i in 0..symbols.len() {
+            if symbols[i].size == 0 {
+                if i + 1 < symbols.len() {
+                    // Set size to the distance to the next symbol
+                    symbols[i].size = symbols[i + 1].addr.saturating_sub(symbols[i].addr);
+                } else {
+                    // Last symbol: round up to next 4KB page boundary and add 4KiB
+                    // This matches perf's behavior: roundup(curr->start, 4096) + 4096
+                    const PAGE_SIZE: u64 = 4096;
+                    let addr = symbols[i].addr;
+                    let end_addr = addr.next_multiple_of(PAGE_SIZE) + PAGE_SIZE;
+                    symbols[i].size = end_addr.saturating_sub(addr);
+                }
+            }
+        }
+
+        // Filter out any symbols that still have zero size
+        symbols.retain(|symbol| symbol.size > 0);
+
         if symbols.is_empty() {
             return Err(anyhow::anyhow!("No symbols found"));
         }
@@ -143,7 +166,6 @@ impl ProcessSymbols {
             return;
         }
 
-        debug!("Loading module symbols at {start_addr:x}-{end_addr:x} (offset: {file_offset:x})");
         let path = module_path.as_ref().to_path_buf();
         match ModuleSymbols::new(module_path, start_addr, end_addr, file_offset) {
             Ok(symbol) => {

src/executor/wall_time/perf/snapshots/codspeed__executor__wall_time__perf__debug_info__tests__cpp_debug_info.snap

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:18b3bab246f006ab09dcb364d019b5714777c93a2be302691fdd3120754e2691
-size 148095
+oid sha256:9af51e449587563ee665bc0c365c1e92b8fdbbd3182d70d026bc9f91890f06d8
+size 148236

src/executor/wall_time/perf/snapshots/codspeed__executor__wall_time__perf__debug_info__tests__golang_debug_info.snap

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:83693652a98c569eec832a5fb6432ade575bf9c150c9621ca37eb47deba40b05
-size 490512
+oid sha256:a80d0a7b245514f01b8719ce71a5776e95c395b1986c5c78cfae948abee23a39
+size 490624

src/executor/wall_time/perf/snapshots/codspeed__executor__wall_time__perf__debug_info__tests__ruff_debug_info.snap

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:c7cc3eab372717be111d0595a1fa6a9c2062d85d4a1f8e8a8e8606f2ecd22cc1
-size 5995725
+oid sha256:be6c5d4b5981911d0ccc635cf0b0e1163ff5879e72b7c3076cac04423856fc68
+size 5996146

src/executor/wall_time/perf/snapshots/codspeed__executor__wall_time__perf__debug_info__tests__rust_divan_debug_info.snap

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:a0c804c19a74c27d25aa0633edb62649ab66ecf1becf282737ae606876d1e24d
-size 519684
+oid sha256:cecbdde3c24b806a75f9e8a438f82419f33f9fcc86b9966352685a35784abec6
+size 520675

src/executor/wall_time/perf/snapshots/codspeed__executor__wall_time__perf__debug_info__tests__the_algorithms_debug_info.snap

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:09c5bee1afe80d0715360d1532eb631336e46d964a2cfabe5b58772e0d18d538
-size 567245
+oid sha256:da29e6ceb514be0437b501e406016656d2ddbc9f1cd0619ea29df64e7bc69e54
+size 568064

src/executor/wall_time/perf/snapshots/codspeed__executor__wall_time__perf__perf_map__tests__cpp_symbols.snap

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:0717a77c9706bebec98155ac1853adccd44ff99036a5d1b3b5c8f556120a407c
-size 102925
+oid sha256:f03bda66a87fef7b32e3aa6ce67c36527cc01b26731e98dff292ac6f889a9431
+size 104083