Remove unused global __Copyright

Unused globals are causing warnings in the runtime due to the list
indices getting out of sync in the list of Globals and ConstantExprs.
This PR stores the copyright statement as metadata, so there is no
unused global inserted into the runtime.

clambcc/clambc-compiler.py

@@ -493,7 +493,7 @@ def createInputSourceFile(clangLLVM: ClangLLVM, name: str, args: list, options:
 
 def optimize(clangLLVM: ClangLLVM, inFile: str, outFile: str, sigFile: str, inputSourceFile: str, standardCompiler: bool) -> int:
 
-    internalizeAPIList = "_Z10entrypointv,entrypoint,__clambc_kind,__clambc_virusname_prefix,__clambc_virusnames,__clambc_filesize,__clambc_match_counts,__clambc_match_offsets,__clambc_pedata,__Copyright"
+    internalizeAPIList = "_Z10entrypointv,entrypoint,__clambc_kind,__clambc_virusname_prefix,__clambc_virusnames,__clambc_filesize,__clambc_match_counts,__clambc_match_offsets,__clambc_pedata"
     if standardCompiler:
         internalizeAPIList += ",main"
 
@@ -509,6 +509,7 @@ def optimize(clangLLVM: ClangLLVM, inFile: str, outFile: str, sigFile: str, inpu
           f' -clambc-preserve-abis' #add fake function calls that use all of
                                    #the arguments so that O3 doesn't change
                                    #the argument lists
+          f' -clambc-copyright-handler'
           f' -O3'
           f' -clambc-preserve-abis' #remove fake function calls because O3 has already run
           f' -clambc-remove-pointer-phis'

libclambcc/CMakeLists.txt

@@ -9,6 +9,7 @@ target_sources(clambcc_obj
         ClamBCLowering/ClamBCLowering.cpp
         ClamBCVerifier/ClamBCVerifier.cpp
         ClamBCLogicalCompiler/ClamBCLogicalCompiler.cpp
+        ClamBCCopyrightHandler/ClamBCCopyrightHandler.cpp
         ClamBCRebuild/ClamBCRebuild.cpp
         ClamBCTrace/ClamBCTrace.cpp
         ClamBCModule/ClamBCModule.cpp

libclambcc/ClamBCCopyrightHandler/ClamBCCopyrightHandler.cpp

@@ -0,0 +1,115 @@
+/*
+ *  Compile LLVM bytecode to logical signatures.
+ *
+ *  Copyright (C) 2023 Sourcefire, Inc.
+ *
+ *  Authors: Andy Ragusa
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *  MA 02110-1301, USA.
+ */
+
+#include "ClamBCModule.h"
+#include <llvm/Support/DataTypes.h>
+#include "../Common/bytecode_api.h"
+#include "clambc.h"
+#include "ClamBCDiagnostics.h"
+#include "ClamBCModule.h"
+#include "ClamBCCommon.h"
+#include "ClamBCUtilities.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringSet.h"
+#include "llvm/Analysis/ConstantFolding.h"
+#include <llvm/IR/DebugInfo.h>
+#include "llvm/Analysis/ValueTracking.h"
+#include <llvm/IR/DerivedTypes.h>
+#include <llvm/IR/IntrinsicInst.h>
+#include <llvm/IR/Module.h>
+#include <llvm/Pass.h>
+//#include <llvm/IR/PassManager.h>
+#include <llvm/IR/LegacyPassManager.h>
+#include <llvm/IR/CallSite.h>
+#include <llvm/IR/ConstantRange.h>
+#include "llvm/Support/Debug.h"
+#include <llvm/IR/InstIterator.h>
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/raw_ostream.h"
+#include <llvm/Support/Process.h>
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/IPO.h"
+#include <llvm/IR/Type.h>
+//#include <llvm/IR/DataLayout.h>
+#include <llvm/Transforms/Utils.h>
+#include <llvm/LinkAllPasses.h>
+
+#define DEBUG_TYPE "copyrighthandler"
+
+using namespace llvm;
+
+namespace
+{
+
+class ClamBCCopyrightHandler : public ModulePass
+{
+  public:
+    static char ID;
+    ClamBCCopyrightHandler()
+        : ModulePass(ID) {}
+
+    virtual bool runOnModule(Module &M);
+
+  private:
+    llvm::Module *pMod;
+};
+
+char ClamBCCopyrightHandler::ID = 0;
+RegisterPass<ClamBCCopyrightHandler> X("clambc-copyright-handler",
+                                       "ClamAV Copyright Handler");
+
+bool ClamBCCopyrightHandler::runOnModule(Module &M)
+{
+    pMod      = &M;
+    bool bRet = false;
+
+    GlobalVariable *gCopyright = pMod->getGlobalVariable("__Copyright");
+    std::string copyright;
+    if (gCopyright && gCopyright->hasDefinitiveInitializer()) {
+        Constant *C = gCopyright->getInitializer();
+        StringRef c;
+        if (!getConstantStringInfo(C, c)) {
+            ClamBCStop("Failed to extract copyright string\n", pMod);
+        }
+        copyright = c.str();
+    }
+
+    if (copyright.length()) {
+        NamedMDNode *Node = M.getOrInsertNamedMetadata("clambc.copyright");
+        MDString *S       = MDString::get(M.getContext(), llvm::StringRef(copyright));
+        MDNode *N         = MDNode::get(M.getContext(), S);
+        Node->addOperand(N);
+        bRet = true;
+    }
+
+    return bRet;
+}
+
+} // namespace
+const PassInfo *const ClamBCCopyrightHandlerID = &X;
+
+llvm::ModulePass *createClamBCCopyrightHandler()
+{
+    return new ClamBCCopyrightHandler();
+}

libclambcc/ClamBCWriter/ClamBCWriter.cpp

@@ -461,6 +461,7 @@ class ClamBCOutputWriter
                 printNumber(Out, 0, false);
                 continue;
             }
+
             Constant *pConst = llvm::cast<Constant>(*I);
             // type of constant
             uint16_t id = pAnalyzer->getTypeID((*I)->getType());
@@ -540,9 +541,11 @@ class ClamBCOutputWriter
         printModuleHeader(*pMod, pAnalyzer, maxLineLength + 1);
         OutReal << Out.str();
 
-        //MemoryBuffer *MB  = nullptr;
-        const char *start     = NULL;
-        std::string copyright = pAnalyzer->getCopyright();
+        const char *start = NULL;
+
+        NamedMDNode *copyrightNode = pMod->getNamedMetadata("clambc.copyright");
+        std::string copyright      = copyrightNode ? cast<MDString>(copyrightNode->getOperand(0)->getOperand(0))->getString() : "";
+
         if (copyright.length()) {
             start = copyright.c_str();
         } else {
@@ -593,6 +596,10 @@ class ClamBCOutputWriter
                 linelength = 0;
             }
         } while (c);
+        //OutReal doesn't appear to add the last newline unless there is something
+        //after it, so there is no newline at the end of the source code printout
+        //without this.
+        OutReal << "\n";
     }
 
     void dumpTypes(llvm::raw_ostream &OS)
@@ -743,7 +750,6 @@ class ClamBCWriter : public ModulePass, public InstVisitor<ClamBCWriter>
 
     bool runOnModule(Module &m)
     {
-
         pMod          = &m;
         pAnalyzer     = &getAnalysis<ClamBCAnalyzer>();
         pOutputWriter = ClamBCOutputWriter::createClamBCOutputWriter(outFile, pMod, pAnalyzer);