[Orc] Refactor ObjectLinkingLayer::addObjectSet to defer loading objects until
they're needed.
Prior to this patch objects were loaded (via RuntimeDyld::loadObject) when they
were added to the ObjectLinkingLayer, but were not relocated and finalized until
a symbol address was requested. In the interim, another object could be loaded
and finalized with the same memory manager, causing relocation/finalization of
the first object to fail (as the first finalization call may have marked the
allocated memory for the first object read-only).
By deferring the loadObject call (and subsequent memory allocations) until an
object file is needed we can avoid prematurely finalizing memory.
llvm-svn: 258185
diff --git a/llvm/unittests/ExecutionEngine/Orc/ObjectLinkingLayerTest.cpp b/llvm/unittests/ExecutionEngine/Orc/ObjectLinkingLayerTest.cpp
index c8c4cfb..f4267c9 100644
--- a/llvm/unittests/ExecutionEngine/Orc/ObjectLinkingLayerTest.cpp
+++ b/llvm/unittests/ExecutionEngine/Orc/ObjectLinkingLayerTest.cpp
@@ -12,6 +12,7 @@
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
+#include "llvm/ExecutionEngine/Orc/NullResolver.h"
#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/LLVMContext.h"
@@ -29,6 +30,13 @@
class SectionMemoryManagerWrapper : public SectionMemoryManager {
public:
int FinalizationCount = 0;
+ int NeedsToReserveAllocationSpaceCount = 0;
+
+ bool needsToReserveAllocationSpace() override {
+ ++NeedsToReserveAllocationSpaceCount;
+ return SectionMemoryManager::needsToReserveAllocationSpace();
+ }
+
bool finalizeMemory(std::string *ErrMsg = 0) override {
++FinalizationCount;
return SectionMemoryManager::finalizeMemory(ErrMsg);
@@ -178,4 +186,68 @@
<< "Extra call to finalize";
}
+TEST_F(ObjectLinkingLayerExecutionTest, NoPrematureAllocation) {
+
+ if (!TM)
+ return;
+
+ ObjectLinkingLayer<> ObjLayer;
+ SimpleCompiler Compile(*TM);
+
+ // Create a pair of unrelated modules:
+ //
+ // Module 1:
+ // int foo() { return 42; }
+ // Module 2:
+ // int bar() { return 7; }
+ //
+ // Both modules will share a memory manager. We want to verify that the
+ // second object is not loaded before the first one is finalized. To do this
+ // in a portable way, we abuse the
+ // RuntimeDyld::MemoryManager::needsToReserveAllocationSpace hook, which is
+ // called once per object before any sections are allocated.
+
+ ModuleBuilder MB1(getGlobalContext(), "", "dummy");
+ {
+ MB1.getModule()->setDataLayout(TM->createDataLayout());
+ Function *BarImpl = MB1.createFunctionDecl<int32_t(void)>("foo");
+ BasicBlock *BarEntry = BasicBlock::Create(getGlobalContext(), "entry",
+ BarImpl);
+ IRBuilder<> Builder(BarEntry);
+ IntegerType *Int32Ty = IntegerType::get(getGlobalContext(), 32);
+ Value *FourtyTwo = ConstantInt::getSigned(Int32Ty, 42);
+ Builder.CreateRet(FourtyTwo);
+ }
+
+ auto Obj1 = Compile(*MB1.getModule());
+ std::vector<object::ObjectFile*> Obj1Set;
+ Obj1Set.push_back(Obj1.getBinary());
+
+ ModuleBuilder MB2(getGlobalContext(), "", "dummy");
+ {
+ MB2.getModule()->setDataLayout(TM->createDataLayout());
+ Function *BarImpl = MB2.createFunctionDecl<int32_t(void)>("bar");
+ BasicBlock *BarEntry = BasicBlock::Create(getGlobalContext(), "entry",
+ BarImpl);
+ IRBuilder<> Builder(BarEntry);
+ IntegerType *Int32Ty = IntegerType::get(getGlobalContext(), 32);
+ Value *Seven = ConstantInt::getSigned(Int32Ty, 7);
+ Builder.CreateRet(Seven);
+ }
+ auto Obj2 = Compile(*MB2.getModule());
+ std::vector<object::ObjectFile*> Obj2Set;
+ Obj2Set.push_back(Obj2.getBinary());
+
+ SectionMemoryManagerWrapper SMMW;
+ NullResolver NR;
+ auto H = ObjLayer.addObjectSet(std::move(Obj1Set), &SMMW, &NR);
+ ObjLayer.addObjectSet(std::move(Obj2Set), &SMMW, &NR);
+ ObjLayer.emitAndFinalize(H);
+
+ // Only one call to needsToReserveAllocationSpace should have been made.
+ EXPECT_EQ(SMMW.NeedsToReserveAllocationSpaceCount, 1)
+ << "More than one call to needsToReserveAllocationSpace "
+ "(multiple unrelated objects loaded prior to finalization)";
+}
+
}