[PATCH] D42842: [MCJIT] Eliminate overhead in case of multiple subsequent calls to llvm::MCJIT::getFunctionAddress

[Mariya Podchishchaeva via Phabricator via llvm-commits]

Fznamznon created this revision.
Herald added a subscriber: llvm-commits.

llvm::MCJIT::finalizeLoadedModules introduces significant overhead per each
call to llvm::MCJIT::getFunctionAddress because it runs symbol relocations,
EH frames registering, and memory page permissions handling every time
although this has to be done only once.

Patch by: Andrey Lizunov.


Repository:
  rL LLVM

https://reviews.llvm.org/D42842

Files:
  lib/ExecutionEngine/MCJIT/MCJIT.cpp
  lib/ExecutionEngine/MCJIT/MCJIT.h


Index: lib/ExecutionEngine/MCJIT/MCJIT.h
===================================================================
--- lib/ExecutionEngine/MCJIT/MCJIT.h
+++ lib/ExecutionEngine/MCJIT/MCJIT.h
@@ -121,6 +121,10 @@
              (FinalizedModules.count(M) != 0);
     }
 
+    bool allModulesAreFinalized() {
+      return (AddedModules.size() == 0) && (LoadedModules.size() == 0);
+    }
+
     void markModuleAsLoaded(Module *M) {
       // This checks against logic errors in the MCJIT implementation.
       // This function should never be called with either a Module that MCJIT
Index: lib/ExecutionEngine/MCJIT/MCJIT.cpp
===================================================================
--- lib/ExecutionEngine/MCJIT/MCJIT.cpp
+++ lib/ExecutionEngine/MCJIT/MCJIT.cpp
@@ -231,6 +231,9 @@
 void MCJIT::finalizeLoadedModules() {
   MutexGuard locked(lock);
 
+  if (OwnedModules.allModulesAreFinalized())
+    return;
+
   // Resolve any outstanding relocations.
   Dyld.resolveRelocations();
 


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