From d88b36448b46f97646438e5a54e6ce07e35b5f38 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 14 Nov 2020 18:36:17 +0100
Subject: [PATCH] UserspaceEmulator: Add some helpers to tidy up
 TrackedChunkedBlock

---
 DevTools/UserspaceEmulator/MallocTracer.cpp | 24 +++++++++++++--------
 DevTools/UserspaceEmulator/MallocTracer.h   |  3 +++
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/DevTools/UserspaceEmulator/MallocTracer.cpp b/DevTools/UserspaceEmulator/MallocTracer.cpp
index 440d85b7b6..d3c8517977 100644
--- a/DevTools/UserspaceEmulator/MallocTracer.cpp
+++ b/DevTools/UserspaceEmulator/MallocTracer.cpp
@@ -72,20 +72,28 @@ void MallocTracer::target_did_malloc(Badge<SoftCPU>, FlatPtr address, size_t siz
             auto& block = const_cast<TrackedChunkedBlock&>(*tracked_chunked_block.value());
             block.address = chunked_block_address;
             block.chunk_size = mmap_region.read32(offsetof(CommonHeader, m_size)).value();
-            auto chunk_count = (ChunkedBlock::block_size - sizeof(ChunkedBlock)) / block.chunk_size;
-            block.mallocations.resize(chunk_count);
-            dbgln("Tracking ChunkedBlock @ {:p} with chunk_size={}, chunk_count={}", block.address, block.chunk_size, chunk_count);
+            block.mallocations.resize((ChunkedBlock::block_size - sizeof(ChunkedBlock)) / block.chunk_size);
+            dbgln("Tracking ChunkedBlock @ {:p} with chunk_size={}, chunk_count={}", block.address, block.chunk_size, block.mallocations.size());
         }
         ASSERT(tracked_chunked_block.has_value());
         auto& block = const_cast<TrackedChunkedBlock&>(*tracked_chunked_block.value());
-        auto chunk_offset = address - (block.address + sizeof(ChunkedBlock));
-        auto chunk_index = chunk_offset / block.chunk_size;
-        block.mallocations[chunk_index] = { address, size, true, false, Emulator::the().raw_backtrace(), Vector<FlatPtr>() };
+        block.mallocation_for_address(address) = { address, size, true, false, Emulator::the().raw_backtrace(), Vector<FlatPtr>() };
     } else {
         m_big_mallocations.append({ address, size, true, false, Emulator::the().raw_backtrace(), Vector<FlatPtr>() });
     }
 }
 
+ALWAYS_INLINE MallocTracer::Mallocation& MallocTracer::TrackedChunkedBlock::mallocation_for_address(FlatPtr address) const
+{
+    return const_cast<Mallocation&>(this->mallocations[chunk_index_for_address(address)]);
+}
+
+ALWAYS_INLINE size_t MallocTracer::TrackedChunkedBlock::chunk_index_for_address(FlatPtr address) const
+{
+    auto chunk_offset = address - (this->address + sizeof(ChunkedBlock));
+    return chunk_offset / this->chunk_size;
+}
+
 void MallocTracer::target_did_free(Badge<SoftCPU>, FlatPtr address)
 {
     if (!address)
@@ -143,9 +151,7 @@ MallocTracer::Mallocation* MallocTracer::find_mallocation(FlatPtr address)
     auto chunked_block = m_chunked_blocks.get(possible_chunked_block);
     if (chunked_block.has_value()) {
         auto& block = *chunked_block.value();
-        auto chunk_offset = address - (block.address + sizeof(ChunkedBlock));
-        auto chunk_index = chunk_offset / block.chunk_size;
-        auto& mallocation = block.mallocations[chunk_index];
+        auto& mallocation = block.mallocation_for_address(address);
         if (mallocation.used) {
             ASSERT(mallocation.contains(address));
             return const_cast<Mallocation*>(&mallocation);
diff --git a/DevTools/UserspaceEmulator/MallocTracer.h b/DevTools/UserspaceEmulator/MallocTracer.h
index 4a90405fe6..aad1d66adb 100644
--- a/DevTools/UserspaceEmulator/MallocTracer.h
+++ b/DevTools/UserspaceEmulator/MallocTracer.h
@@ -69,6 +69,9 @@ private:
         FlatPtr address { 0 };
         size_t chunk_size { 0 };
 
+        size_t chunk_index_for_address(FlatPtr) const;
+        Mallocation& mallocation_for_address(FlatPtr) const;
+
         Vector<Mallocation> mallocations;
     };