[SharedCache] Make it faster to look up which image contains an address

`MemoryRegion` now tracks the start address of the image to which it
belongs. `SharedCache::HeaderForAddress` uses the existing address range
map to quickly find the `MemoryRegion` for a given address, and from
there can look up the image via its start address.

Some extra logic is added to `CacheInfo::Load` to populate the image
start address on `MemoryRegion` when loading from metadata that predates
this change.

The result is that `HeaderForAddress` is no longer the most expensive
part of `FindSymbolAtAddrAndApplyToAddr`.

1 files changed, 7 insertions, 0 deletions

diff --git a/view/sharedcache/core/SharedCache.h b/view/sharedcache/core/SharedCache.h
index 97da0880..d696154c 100644
--- a/view/sharedcache/core/SharedCache.h
+++ b/view/sharedcache/core/SharedCache.h
@@ -41,6 +41,9 @@ namespace SharedCacheCore {
 		std::string prettyName;
 		uint64_t start;
 		uint64_t size;
+		// Start address of the image this region belongs to.
+		// 0 if the region does not belong to any image.
+		uint64_t imageStart = 0;
 		BNSegmentFlag flags;
 		Type type;
 
@@ -55,6 +58,7 @@ namespace SharedCacheCore {
 			MSS(prettyName);
 			MSS(start);
 			MSS(size);
+			MSS(imageStart);
 			MSS_CAST(flags, uint64_t);
 			MSS_CAST(type, uint8_t);
 		}
@@ -67,6 +71,9 @@ namespace SharedCacheCore {
 			region.MSL(size);
 			region.MSL_CAST(flags, uint64_t, BNSegmentFlag);
 			region.MSL_CAST(type, uint8_t, Type);
+			if (context.doc.HasMember("imageStart"))
+				region.MSL(imageStart);
+
 			return region;
 		}
 	};