LinuxSyscalls: Use a multimap to store MappedResources

This allows for creating separate MappedResources when an ELF file is mapped
multiple times at different base addresses.

Source/Tools/LinuxEmulation/LinuxSyscalls/SyscallsSMCTracking.cpp

@@ -388,11 +388,15 @@ std::optional<SyscallHandler::LateApplyExtendedVolatileMetadata> SyscallHandler:
     char Tmp[PATH_MAX];
     auto PathLength = FEX::get_fdpath(fd, Tmp);
 
-    auto [Iter, Inserted] = VMATracking.InsertMappedResource(mrid, {nullptr, nullptr, 0});
-    Resource = &Iter->second;
-    if (Inserted) {
-      Resource->Iterator = Iter;
+    auto [ResourceIt, ResourceEnd] = VMATracking.FindResources(mrid);
+    bool Inserted = false;
+    if (ResourceIt == ResourceEnd) {
+      // Create a new MappedResource for previously unseen file
+      ResourceIt = VMATracking.InsertMappedResource(mrid, {nullptr, nullptr, 0});
+      ResourceIt->second.Iterator = ResourceIt;
+      Inserted = true;
     }
+    Resource = &ResourceIt->second;
 
     // Only handle FDs that are backed by regular files that are executable
     if (PathLength != -1 && S_ISREG(buf.st_mode) && (buf.st_mode & S_IXUSR)) {
@@ -419,8 +423,10 @@ std::optional<SyscallHandler::LateApplyExtendedVolatileMetadata> SyscallHandler:
   } else if (flags & MAP_SHARED) {
     VMATracking::MRID mrid {VMATracking::SpecialDev::Anon, AnonSharedId++};
 
-    auto [Iter, Inserted] = VMATracking.InsertMappedResource(mrid, {nullptr, nullptr, 0});
-    LOGMAN_THROW_A_FMT(Inserted == true, "VMA tracking error");
+    auto [Iter, IterEnd] = VMATracking.FindResources(mrid);
+    LOGMAN_THROW_A_FMT(Iter == IterEnd, "VMA tracking error");
+
+    Iter = VMATracking.InsertMappedResource(mrid, {nullptr, nullptr, 0});
     Resource = &Iter->second;
     Resource->Iterator = Iter;
   } else {
@@ -480,11 +486,12 @@ void SyscallHandler::TrackMremap(FEXCore::Core::InternalThreadState* Thread, uin
 void SyscallHandler::TrackShmat(FEXCore::Core::InternalThreadState* Thread, int shmid, uint64_t shmaddr, int shmflg, uint64_t Length) {
   VMATracking::MRID mrid {VMATracking::SpecialDev::SHM, static_cast<uint64_t>(shmid)};
 
-  auto [Iter, Inserted] = VMATracking.InsertMappedResource(mrid, {nullptr, nullptr, Length});
-  auto Resource = &Iter->second;
-  if (Inserted) {
-    Resource->Iterator = Iter;
+  auto [Iter, IterEnd] = VMATracking.FindResources(mrid);
+  if (Iter == IterEnd) {
+    Iter = VMATracking.InsertMappedResource(mrid, {nullptr, nullptr, Length});
+    Iter->second.Iterator = Iter;
   }
+  auto Resource = &Iter->second;
   VMATracking.TrackVMARange(CTX, Resource, shmaddr, 0, Length, VMATracking::VMAFlags::fromFlags(MAP_SHARED), VMATracking::VMAProt::fromSHM(shmflg));
 }
 

Source/Tools/LinuxEmulation/LinuxSyscalls/SyscallsVMATracking.h

@@ -30,9 +30,16 @@ struct MRID {
 
 struct VMAEntry;
 
-// Used to all MAP_SHARED VMAs of a system resource.
+/**
+ * Meta data associated to one system resource.
+ *
+ * Typically there is one instance of this type per ELF/PE file or special device.
+ * However if an ELF/PE file is mapped multiple times at different base addresses,
+ * there will be one separate MappedResource for each base address. The MRID
+ * is the same in this case.
+ */
 struct MappedResource {
-  using ContainerType = fextl::map<MRID, MappedResource>;
+  using ContainerType = fextl::multimap<MRID, MappedResource>;
 
   fextl::unique_ptr<FEXCore::ExecutableFileInfo> MappedFile;
   // Pointer to lowest memory range this file is mapped to
@@ -116,6 +123,14 @@ struct VMATracking {
     return MappedResources.emplace(mrid, std::move(Resource));
   }
 
+  // Returns an iterator pair spanning the range of all MappedResources matching the given MRID.
+  // Typically there is only one associated resource, however sometimes the same file gets mapped
+  // multiple times at different base addresses. In that case, each MappedResource will cover an
+  // exclusive set of VMAEntries that refer to a consistent base mapping address.
+  inline auto FindResources(const MRID& mrid) {
+    return MappedResources.equal_range(mrid);
+  }
+
 private:
   MappedResource::ContainerType MappedResources;
 };