[llvm] r227228 - [ExecutionEngine] Add weak symbol support to RuntimeDyld
Keno Fischer
kfischer at college.harvard.edu
Tue Jan 27 12:02:31 PST 2015
Author: kfischer
Date: Tue Jan 27 14:02:31 2015
New Revision: 227228
URL: http://llvm.org/viewvc/llvm-project?rev=227228&view=rev
Log:
[ExecutionEngine] Add weak symbol support to RuntimeDyld
Support weak symbols by first looking up if there is an externally visible symbol we can find,
and only if that fails using the one in the object file we're loading.
Reviewed By: lhames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D6950
Modified:
llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
llvm/trunk/unittests/ExecutionEngine/MCJIT/CMakeLists.txt
llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTest.cpp
llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h
llvm/trunk/unittests/ExecutionEngine/MCJIT/Makefile
Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp?rev=227228&r1=227227&r2=227228&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp Tue Jan 27 14:02:31 2015
@@ -168,6 +168,7 @@ RuntimeDyldImpl::loadObjectImpl(const ob
uint32_t Flags = I->getFlags();
bool IsCommon = Flags & SymbolRef::SF_Common;
+ bool IsWeak = Flags & SymbolRef::SF_Weak;
if (IsCommon)
CommonSymbols.push_back(*I);
else {
@@ -188,6 +189,11 @@ RuntimeDyldImpl::loadObjectImpl(const ob
continue;
StringRef SectionData;
Check(SI->getContents(SectionData));
+ // TODO: It make make sense to delay emitting the section for weak
+ // symbols until they are actually required, but that's not possible
+ // currently, because we only know whether we will need the symbol
+ // in resolveRelocations, which happens after we have already finalized
+ // the Load.
bool IsCode = SI->isText();
unsigned SectionID =
findOrEmitSection(Obj, *SI, IsCode, LocalSections);
@@ -198,7 +204,11 @@ RuntimeDyldImpl::loadObjectImpl(const ob
SymbolInfo::Visibility Vis =
(Flags & SymbolRef::SF_Exported) ?
SymbolInfo::Default : SymbolInfo::Hidden;
- GlobalSymbolTable[Name] = SymbolInfo(SectionID, SectOffset, Vis);
+ if (!IsWeak) {
+ GlobalSymbolTable[Name] = SymbolInfo(SectionID, SectOffset, Vis);
+ } else {
+ WeakSymbolTable[Name] = SymbolInfo(SectionID, SectOffset, Vis);
+ }
}
}
}
@@ -768,6 +778,21 @@ void RuntimeDyldImpl::resolveExternalSym
SymInfo.getOffset();
}
+ // If we didn't find the symbol yet, and it is present in the weak symbol
+ // table, the definition from this object file needs to be used, so emit
+ // it now
+ if (!Addr) {
+ RTDyldSymbolTable::const_iterator Loc = WeakSymbolTable.find(Name);
+ if (Loc != WeakSymbolTable.end()) {
+ SymbolInfo SymInfo = Loc->second;
+ Addr = getSectionLoadAddress(SymInfo.getSectionID()) + SymInfo.getOffset();
+ // Since the weak symbol is now, materialized, add it to the
+ // GlobalSymbolTable. If somebody later asks the ExecutionEngine
+ // for the address of this symbol that's where it'll look
+ GlobalSymbolTable[Name] = SymInfo;
+ }
+ }
+
// FIXME: Implement error handling that doesn't kill the host program!
if (!Addr)
report_fatal_error("Program used external function '" + Name +
@@ -784,6 +809,7 @@ void RuntimeDyldImpl::resolveExternalSym
ExternalSymbolRelocations.erase(i);
}
+ WeakSymbolTable.clear();
}
//===----------------------------------------------------------------------===//
Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp?rev=227228&r1=227227&r2=227228&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp Tue Jan 27 14:02:31 2015
@@ -947,6 +947,7 @@ relocation_iterator RuntimeDyldELF::proc
break;
}
case SymbolRef::ST_Data:
+ case SymbolRef::ST_Function:
case SymbolRef::ST_Unknown: {
Value.SymbolName = TargetName.data();
Value.Addend = Addend;
Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h?rev=227228&r1=227227&r2=227228&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h Tue Jan 27 14:02:31 2015
@@ -203,6 +203,9 @@ protected:
// A global symbol table for symbols from all loaded modules.
RTDyldSymbolTable GlobalSymbolTable;
+ // Like the global symbol table but for weak symbols
+ RTDyldSymbolTable WeakSymbolTable;
+
// Keep a map of common symbols to their info pairs
typedef std::vector<SymbolRef> CommonSymbolList;
Modified: llvm/trunk/unittests/ExecutionEngine/MCJIT/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ExecutionEngine/MCJIT/CMakeLists.txt?rev=227228&r1=227227&r2=227228&view=diff
==============================================================================
--- llvm/trunk/unittests/ExecutionEngine/MCJIT/CMakeLists.txt (original)
+++ llvm/trunk/unittests/ExecutionEngine/MCJIT/CMakeLists.txt Tue Jan 27 14:02:31 2015
@@ -1,5 +1,6 @@
set(LLVM_LINK_COMPONENTS
Analysis
+ AsmParser
Core
ExecutionEngine
IPO
Modified: llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTest.cpp?rev=227228&r1=227227&r2=227228&view=diff
==============================================================================
--- llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTest.cpp (original)
+++ llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTest.cpp Tue Jan 27 14:02:31 2015
@@ -13,6 +13,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/MCJIT.h"
+#include "llvm/Support/DynamicLibrary.h"
#include "MCJITTestBase.h"
#include "gtest/gtest.h"
@@ -199,4 +200,45 @@ TEST_F(MCJITTest, multiple_decl_lookups)
EXPECT_EQ(A, B) << "Repeat calls to getPointerToFunction fail.";
}
+// Test weak symbol linking when the weak symbol is present in a shared
+// library
+TEST_F(MCJITTest, weak_symbol_present) {
+ SKIP_UNSUPPORTED_PLATFORM;
+
+ int FakeWeakSymbol;
+ llvm::sys::DynamicLibrary::AddSymbol("FakeWeakSymbol", &FakeWeakSymbol);
+ createJITFromAssembly(
+ "$FakeWeakSymbol = comdat any\n"
+ "@FakeWeakSymbol = linkonce_odr global i32 42, comdat, align 4\n"
+ "define i32 @weak_test(i32* %arg) {\n"
+ " %r = icmp eq i32* %arg, @FakeWeakSymbol\n"
+ " %ret = zext i1 %r to i32\n"
+ " ret i32 %ret\n"
+ " }");
+
+ uint64_t Addr = TheJIT->getFunctionAddress("weak_test");;
+ EXPECT_TRUE(Addr != 0);
+ int32_t(*FuncPtr)(int32_t *) = (int32_t(*)(int32_t *))Addr;
+ EXPECT_EQ(FuncPtr(&FakeWeakSymbol),1);
+ EXPECT_TRUE(TheJIT->getGlobalValueAddress("FakeWeakSymbol") == 0);
+}
+
+// Test weak symbol linking when the weak symbol is not present in a
+// shared library
+TEST_F(MCJITTest, weak_symbol_absent) {
+ SKIP_UNSUPPORTED_PLATFORM;
+
+ SMDiagnostic Error;
+ createJITFromAssembly(
+ " $FakeWeakSymbol2 = comdat any\n"
+ " @FakeWeakSymbol2 = linkonce_odr global i32 42, comdat, align 4\n"
+ " define i32* @get_weak() {\n"
+ " ret i32* @FakeWeakSymbol2\n"
+ " }\n");
+ void*(*FuncPtr)() =
+ (void*(*)(void))TheJIT->getFunctionAddress("get_weak");
+ EXPECT_EQ(FuncPtr(),(void*)TheJIT->getGlobalValueAddress("FakeWeakSymbol2"));
+}
+
+
}
Modified: llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h?rev=227228&r1=227227&r2=227228&view=diff
==============================================================================
--- llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h (original)
+++ llvm/trunk/unittests/ExecutionEngine/MCJIT/MCJITTestBase.h Tue Jan 27 14:02:31 2015
@@ -18,6 +18,7 @@
#define LLVM_UNITTESTS_EXECUTIONENGINE_MCJIT_MCJITTESTBASE_H
#include "MCJITTestAPICommon.h"
+#include "llvm/AsmParser/Parser.h"
#include "llvm/Config/config.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
@@ -27,6 +28,8 @@
#include "llvm/IR/Module.h"
#include "llvm/IR/TypeBuilder.h"
#include "llvm/Support/CodeGen.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
namespace llvm {
@@ -338,6 +341,21 @@ protected:
assert(TheJIT.get() != NULL && "error creating MCJIT with EngineBuilder");
}
+ void createJITFromAssembly(const char *Test) {
+ SMDiagnostic Error;
+ M = parseAssemblyString(Test, Error, Context);
+
+ std::string errMsg;
+ raw_string_ostream os(errMsg);
+ Error.print("", os);
+
+ // A failure here means that the test itself is buggy.
+ if (!M)
+ report_fatal_error(os.str().c_str());
+
+ createJIT(std::move(M));
+ }
+
CodeGenOpt::Level OptLevel;
Reloc::Model RelocModel;
CodeModel::Model CodeModel;
Modified: llvm/trunk/unittests/ExecutionEngine/MCJIT/Makefile
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ExecutionEngine/MCJIT/Makefile?rev=227228&r1=227227&r2=227228&view=diff
==============================================================================
--- llvm/trunk/unittests/ExecutionEngine/MCJIT/Makefile (original)
+++ llvm/trunk/unittests/ExecutionEngine/MCJIT/Makefile Tue Jan 27 14:02:31 2015
@@ -9,7 +9,7 @@
LEVEL = ../../..
TESTNAME = MCJIT
-LINK_COMPONENTS := core ipo mcjit native support
+LINK_COMPONENTS := core asmparser ipo mcjit native support
include $(LEVEL)/Makefile.config
include $(LLVM_SRC_ROOT)/unittests/Makefile.unittest
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