[llvm] r229973 - [Orc] Add a new JITSymbol constructor to build a symbol from an existing address.
Lang Hames
lhames at gmail.com
Thu Feb 19 22:48:29 PST 2015
Author: lhames
Date: Fri Feb 20 00:48:29 2015
New Revision: 229973
URL: http://llvm.org/viewvc/llvm-project?rev=229973&view=rev
Log:
[Orc] Add a new JITSymbol constructor to build a symbol from an existing address.
This constructor is more efficient for symbols that have already been emitted,
since it avoids the construction/execution of a std::function.
Update the ObjectLinkingLayer to use this new constructor where possible.
Modified:
llvm/trunk/include/llvm/ExecutionEngine/Orc/JITSymbol.h
llvm/trunk/include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h
Modified: llvm/trunk/include/llvm/ExecutionEngine/Orc/JITSymbol.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ExecutionEngine/Orc/JITSymbol.h?rev=229973&r1=229972&r2=229973&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ExecutionEngine/Orc/JITSymbol.h (original)
+++ llvm/trunk/include/llvm/ExecutionEngine/Orc/JITSymbol.h Fri Feb 20 00:48:29 2015
@@ -28,10 +28,25 @@ class JITSymbol {
public:
typedef std::function<TargetAddress()> GetAddressFtor;
+ /// @brief Create a 'null' symbol that represents failure to find a symbol
+ /// definition.
JITSymbol(std::nullptr_t) : CachedAddr(0) {}
+ /// @brief Create a symbol for a definition with a known address.
+ JITSymbol(TargetAddress Addr)
+ : CachedAddr(Addr) {}
+
+ /// @brief Create a symbol for a definition that doesn't have a known address
+ /// yet.
+ /// @param GetAddress A functor to materialize a definition (fixing the
+ /// address) on demand.
+ ///
+ /// This constructor allows a JIT layer to provide a reference to a symbol
+ /// definition without actually materializing the definition up front. The
+ /// user can materialize the definition at any time by calling the getAddress
+ /// method.
JITSymbol(GetAddressFtor GetAddress)
- : CachedAddr(0), GetAddress(std::move(GetAddress)) {}
+ : CachedAddr(0), GetAddress(std::move(GetAddress)) {}
/// @brief Returns true if the symbol exists, false otherwise.
explicit operator bool() const { return CachedAddr || GetAddress; }
Modified: llvm/trunk/include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h?rev=229973&r1=229972&r2=229973&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h (original)
+++ llvm/trunk/include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h Fri Feb 20 00:48:29 2015
@@ -213,16 +213,27 @@ public:
/// given object set.
JITSymbol findSymbolIn(ObjSetHandleT H, StringRef Name,
bool ExportedSymbolsOnly) {
- if (auto Addr = H->getSymbolAddress(Name, ExportedSymbolsOnly))
- return JITSymbol(
- [this, Addr, H](){
- if (H->NeedsFinalization()) {
- H->Finalize();
- if (NotifyFinalized)
- NotifyFinalized(H);
- }
- return Addr;
- });
+ if (auto Addr = H->getSymbolAddress(Name, ExportedSymbolsOnly)) {
+ if (!H->NeedsFinalization()) {
+ // If this instance has already been finalized then we can just return
+ // the address.
+ return JITSymbol(Addr);
+ } else {
+ // If this instance needs finalization return a functor that will do it.
+ // The functor still needs to double-check whether finalization is
+ // required, in case someone else finalizes this set before the functor
+ // is called.
+ return JITSymbol(
+ [this, Addr, H]() {
+ if (H->NeedsFinalization()) {
+ H->Finalize();
+ if (NotifyFinalized)
+ NotifyFinalized(H);
+ }
+ return Addr;
+ });
+ }
+ }
return nullptr;
}
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