[llvm-commits] [llvm] r97737 - in /llvm/trunk: lib/ExecutionEngine/JIT/JITEmitter.cpp unittests/ExecutionEngine/JIT/JITTest.cpp
Jeffrey Yasskin
jyasskin at google.com
Thu Mar 4 11:45:09 PST 2010
Author: jyasskin
Date: Thu Mar 4 13:45:09 2010
New Revision: 97737
URL: http://llvm.org/viewvc/llvm-project?rev=97737&view=rev
Log:
Fix PR6360. It's easy for a stub's address to escape to user code, so we can't
just count references to it from JIT output to decide when to destroy it. This
patch waits to destroy the JIT's memory of a stub until the Function it refers
to is destroyed. External function stubs and GVIndirectSyms aren't destroyed
until the JIT itself is.
Modified:
llvm/trunk/lib/ExecutionEngine/JIT/JITEmitter.cpp
llvm/trunk/unittests/ExecutionEngine/JIT/JITTest.cpp
Modified: llvm/trunk/lib/ExecutionEngine/JIT/JITEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/JIT/JITEmitter.cpp?rev=97737&r1=97736&r2=97737&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/JIT/JITEmitter.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/JIT/JITEmitter.cpp Thu Mar 4 13:45:09 2010
@@ -226,8 +226,6 @@
void getRelocatableGVs(SmallVectorImpl<GlobalValue*> &GVs,
SmallVectorImpl<void*> &Ptrs);
- GlobalValue *invalidateStub(void *Stub);
-
/// getGOTIndexForAddress - Return a new or existing index in the GOT for
/// an address. This function only manages slots, it does not manage the
/// contents of the slots or the memory associated with the GOT.
@@ -371,16 +369,6 @@
ValueMap<const Function *, EmittedCode,
EmittedFunctionConfig> EmittedFunctions;
- // CurFnStubUses - For a given Function, a vector of stubs that it
- // references. This facilitates the JIT detecting that a stub is no
- // longer used, so that it may be deallocated.
- DenseMap<AssertingVH<const Function>, SmallVector<void*, 1> > CurFnStubUses;
-
- // StubFnRefs - For a given pointer to a stub, a set of Functions which
- // reference the stub. When the count of a stub's references drops to zero,
- // the stub is unused.
- DenseMap<void *, SmallPtrSet<const Function*, 1> > StubFnRefs;
-
DILocation PrevDLT;
/// Instance of the JIT
@@ -469,11 +457,6 @@
/// function body.
void deallocateMemForFunction(const Function *F);
- /// AddStubToCurrentFunction - Mark the current function being JIT'd as
- /// using the stub at the specified address. Allows
- /// deallocateMemForFunction to also remove stubs no longer referenced.
- void AddStubToCurrentFunction(void *Stub);
-
virtual void processDebugLoc(DebugLoc DL, bool BeforePrintingInsn);
virtual void emitLabel(uint64_t LabelID) {
@@ -725,42 +708,6 @@
}
}
-GlobalValue *JITResolver::invalidateStub(void *Stub) {
- MutexGuard locked(TheJIT->lock);
-
- // Remove the stub from the StubToResolverMap.
- StubToResolverMap->UnregisterStubResolver(Stub);
-
- GlobalToIndirectSymMapTy &GM = state.getGlobalToIndirectSymMap(locked);
-
- // Look up the cheap way first, to see if it's a function stub we are
- // invalidating. If so, remove it from both the forward and reverse maps.
- if (Function *F = state.EraseStub(locked, Stub)) {
- return F;
- }
-
- // Otherwise, it might be an indirect symbol stub. Find it and remove it.
- for (GlobalToIndirectSymMapTy::iterator i = GM.begin(), e = GM.end();
- i != e; ++i) {
- if (i->second != Stub)
- continue;
- GlobalValue *GV = i->first;
- GM.erase(i);
- return GV;
- }
-
- // Lastly, check to see if it's in the ExternalFnToStubMap.
- for (std::map<void *, void *>::iterator i = ExternalFnToStubMap.begin(),
- e = ExternalFnToStubMap.end(); i != e; ++i) {
- if (i->second != Stub)
- continue;
- ExternalFnToStubMap.erase(i);
- break;
- }
-
- return 0;
-}
-
/// JITCompilerFn - This function is called when a lazy compilation stub has
/// been entered. It looks up which function this stub corresponds to, compiles
/// it if necessary, then returns the resultant function pointer.
@@ -846,7 +793,6 @@
// that we're returning the same address for the function as any previous
// call. TODO: Yes, this is wrong. The lazy stub isn't guaranteed to be
// close enough to call.
- AddStubToCurrentFunction(FnStub);
return FnStub;
}
@@ -863,18 +809,10 @@
return TheJIT->getPointerToFunction(F);
}
- // Otherwise, we may need a to emit a stub, and, conservatively, we
- // always do so.
- void *StubAddr = Resolver.getLazyFunctionStub(F);
-
- // Add the stub to the current function's list of referenced stubs, so we can
- // deallocate them if the current function is ever freed. It's possible to
- // return null from getLazyFunctionStub in the case of a weak extern that
- // fails to resolve.
- if (StubAddr)
- AddStubToCurrentFunction(StubAddr);
-
- return StubAddr;
+ // Otherwise, we may need a to emit a stub, and, conservatively, we always do
+ // so. Note that it's possible to return null from getLazyFunctionStub in the
+ // case of a weak extern that fails to resolve.
+ return Resolver.getLazyFunctionStub(F);
}
void *JITEmitter::getPointerToGVIndirectSym(GlobalValue *V, void *Reference) {
@@ -882,24 +820,9 @@
// resolved address.
void *GVAddress = getPointerToGlobal(V, Reference, false);
void *StubAddr = Resolver.getGlobalValueIndirectSym(V, GVAddress);
-
- // Add the stub to the current function's list of referenced stubs, so we can
- // deallocate them if the current function is ever freed.
- AddStubToCurrentFunction(StubAddr);
-
return StubAddr;
}
-void JITEmitter::AddStubToCurrentFunction(void *StubAddr) {
- assert(CurFn && "Stub added to current function, but current function is 0!");
-
- SmallVectorImpl<void*> &StubsUsed = CurFnStubUses[CurFn];
- StubsUsed.push_back(StubAddr);
-
- SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[StubAddr];
- FnRefs.insert(CurFn);
-}
-
void JITEmitter::processDebugLoc(DebugLoc DL, bool BeforePrintingInsn) {
if (!DL.isUnknown()) {
DILocation CurDLT = EmissionDetails.MF->getDILocation(DL);
@@ -1407,40 +1330,6 @@
if (JITEmitDebugInfo) {
DR->UnregisterFunction(F);
}
-
- // If the function did not reference any stubs, return.
- if (CurFnStubUses.find(F) == CurFnStubUses.end())
- return;
-
- // For each referenced stub, erase the reference to this function, and then
- // erase the list of referenced stubs.
- SmallVectorImpl<void *> &StubList = CurFnStubUses[F];
- for (unsigned i = 0, e = StubList.size(); i != e; ++i) {
- void *Stub = StubList[i];
-
- // If we already invalidated this stub for this function, continue.
- if (StubFnRefs.count(Stub) == 0)
- continue;
-
- SmallPtrSet<const Function *, 1> &FnRefs = StubFnRefs[Stub];
- FnRefs.erase(F);
-
- // If this function was the last reference to the stub, invalidate the stub
- // in the JITResolver. Were there a memory manager deallocateStub routine,
- // we could call that at this point too.
- if (FnRefs.empty()) {
- DEBUG(dbgs() << "\nJIT: Invalidated Stub at [" << Stub << "]\n");
- StubFnRefs.erase(Stub);
-
- // Invalidate the stub. If it is a GV stub, update the JIT's global
- // mapping for that GV to zero.
- GlobalValue *GV = Resolver.invalidateStub(Stub);
- if (GV) {
- TheJIT->updateGlobalMapping(GV, 0);
- }
- }
- }
- CurFnStubUses.erase(F);
}
Modified: llvm/trunk/unittests/ExecutionEngine/JIT/JITTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ExecutionEngine/JIT/JITTest.cpp?rev=97737&r1=97736&r2=97737&view=diff
==============================================================================
--- llvm/trunk/unittests/ExecutionEngine/JIT/JITTest.cpp (original)
+++ llvm/trunk/unittests/ExecutionEngine/JIT/JITTest.cpp Thu Mar 4 13:45:09 2010
@@ -655,6 +655,29 @@
EXPECT_EQ(42, *********test());
}
+TEST_F(JITTest, EscapedLazyStubStillCallable) {
+ TheJIT->DisableLazyCompilation(false);
+ LoadAssembly("define internal i32 @stubbed() { "
+ " ret i32 42 "
+ "} "
+ " "
+ "define i32()* @get_stub() { "
+ " ret i32()* @stubbed "
+ "} ");
+ typedef int32_t(*StubTy)();
+
+ // Call get_stub() to get the address of @stubbed without actually JITting it.
+ Function *get_stubIR = M->getFunction("get_stub");
+ StubTy (*get_stub)() = reinterpret_cast<StubTy(*)()>(
+ (intptr_t)TheJIT->getPointerToFunction(get_stubIR));
+ StubTy stubbed = get_stub();
+ // Now get_stubIR is the only reference to stubbed's stub.
+ get_stubIR->eraseFromParent();
+ // Now there are no references inside the JIT, but we've got a pointer outside
+ // it. The stub should be callable and return the right value.
+ EXPECT_EQ(42, stubbed());
+}
+
// Converts the LLVM assembly to bitcode and returns it in a std::string. An
// empty string indicates an error.
std::string AssembleToBitcode(LLVMContext &Context, const char *Assembly) {
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