Adds helper function to determine if a function was generated by phasar (#665)

* Adds helper function to determine if a function was generated by phasar

During global analysis, phasar generates helper function to correctly
handle global ctors/dtors and other global code fragments. With the new
checking function, users can determine whether a given function was
generated by phasar or not, e.g., for global analysis.

* get rid of magic string literals that name the various generated functions of phasar's global ctor/dtor modelling

* minor style

---------

Co-authored-by: Martin Mory <[email protected]>
Co-authored-by: Martin Mory <[email protected]>
Co-authored-by: Fabian Schiebel <[email protected]>

Author: 4 people

include/phasar/PhasarLLVM/ControlFlow/LLVMBasedICFG.h

@@ -55,6 +55,15 @@ class LLVMBasedICFG : public LLVMBasedCFG, public ICFGBase<LLVMBasedICFG> {
   static constexpr llvm::StringLiteral GlobalCRuntimeModelName =
       "__psrCRuntimeGlobalCtorsModel";
 
+  static constexpr llvm::StringLiteral GlobalCRuntimeDtorModelName =
+      "__psrCRuntimeGlobalDtorsModel";
+
+  static constexpr llvm::StringLiteral GlobalCRuntimeDtorsCallerName =
+      "__psrGlobalDtorsCaller";
+
+  static constexpr llvm::StringLiteral GlobalCRuntimeUserEntrySelectorName =
+      "__psrCRuntimeUserEntrySelector";
+
   /// Constructs the ICFG based on the given IRDB and the entry-points using a
   /// fixpoint iteration. This may take a long time.
   ///
@@ -119,6 +128,9 @@ class LLVMBasedICFG : public LLVMBasedCFG, public ICFGBase<LLVMBasedICFG> {
   /// Gets the underlying IRDB
   [[nodiscard]] LLVMProjectIRDB *getIRDB() const noexcept { return IRDB; }
 
+  /// Returns true, if a function was generated by phasar.
+  [[nodiscard]] static bool isPhasarGenerated(const llvm::Function &) noexcept;
+
   using CFGBase::print;
   using ICFGBase::print;
 

lib/PhasarLLVM/ControlFlow/LLVMBasedICFG.cpp

@@ -29,6 +29,7 @@
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -380,6 +381,19 @@ LLVMBasedICFG::LLVMBasedICFG(LLVMProjectIRDB *IRDB,
 
 LLVMBasedICFG::~LLVMBasedICFG() = default;
 
+bool LLVMBasedICFG::isPhasarGenerated(const llvm::Function &F) noexcept {
+  if (F.hasName()) {
+    llvm::StringRef FunctionName = F.getName();
+    return llvm::StringSwitch<bool>(FunctionName)
+        .Cases(GlobalCRuntimeModelName, GlobalCRuntimeDtorModelName,
+               GlobalCRuntimeDtorsCallerName,
+               GlobalCRuntimeUserEntrySelectorName, true)
+        .Default(false);
+  }
+
+  return false;
+}
+
 [[nodiscard]] FunctionRange LLVMBasedICFG::getAllFunctionsImpl() const {
   return IRDB->getAllFunctions();
 }

lib/PhasarLLVM/ControlFlow/LLVMBasedICFGGlobalsImpl.cpp

@@ -124,9 +124,10 @@ static llvm::Function *createDtorCallerForModule(
         &RegisteredDtors) {
 
   auto *PhasarDtorCaller = llvm::cast<llvm::Function>(
-      Mod.getOrInsertFunction("__psrGlobalDtorsCaller." +
-                                  getReducedModuleName(Mod),
-                              llvm::Type::getVoidTy(Mod.getContext()))
+      Mod.getOrInsertFunction(
+             LLVMBasedICFG::GlobalCRuntimeDtorsCallerName.str() + '.' +
+                 getReducedModuleName(Mod),
+             llvm::Type::getVoidTy(Mod.getContext()))
           .getCallee());
 
   auto *BB =
@@ -195,7 +196,7 @@ static std::pair<llvm::Function *, bool> buildCRuntimeGlobalDtorsModel(
 
   auto &CTX = M.getContext();
   auto *Cleanup = llvm::cast<llvm::Function>(
-      M.getOrInsertFunction("__psrCRuntimeGlobalDtorsModel",
+      M.getOrInsertFunction(LLVMBasedICFG::GlobalCRuntimeDtorModelName,
                             llvm::Type::getVoidTy(CTX))
           .getCallee());
 
@@ -301,7 +302,7 @@ llvm::Function *LLVMBasedICFG::buildCRuntimeGlobalCtorsDtorsModel(
   } else {
 
     auto UEntrySelectorFn = M.getOrInsertFunction(
-        "__psrCRuntimeUserEntrySelector", llvm::Type::getInt32Ty(CTX));
+        GlobalCRuntimeUserEntrySelectorName, llvm::Type::getInt32Ty(CTX));
 
     auto *UEntrySelector = IRB.CreateCall(UEntrySelectorFn);
 

unittests/PhasarLLVM/ControlFlow/LLVMBasedICFGGlobCtorDtorTest.cpp

@@ -93,9 +93,10 @@ TEST_F(LLVMBasedICFGGlobCtorDtorTest, CtorTest) {
 
   // GlobalCtor->print(llvm::outs());
 
-  ensureFunctionOrdering(GlobalCtor, ICFG,
-                         {{"_GLOBAL__sub_I_globals_ctor_1.cpp", "main"},
-                          {"main", "__psrCRuntimeGlobalDtorsModel"}});
+  ensureFunctionOrdering(
+      GlobalCtor, ICFG,
+      {{"_GLOBAL__sub_I_globals_ctor_1.cpp", "main"},
+       {"main", LLVMBasedICFG::GlobalCRuntimeDtorModelName}});
 }
 
 TEST_F(LLVMBasedICFGGlobCtorDtorTest, CtorTest2) {
@@ -144,10 +145,12 @@ TEST_F(LLVMBasedICFGGlobCtorDtorTest, DtorTest1) {
   ensureFunctionOrdering(
       GlobalCtor, ICFG,
       {{"_GLOBAL__sub_I_globals_dtor_1.cpp", "main"},
-       {"main", "__psrGlobalDtorsCaller.globals_dtor_1_cpp.ll"}});
+       {"main", LLVMBasedICFG::GlobalCRuntimeDtorsCallerName.str() +
+                    ".globals_dtor_1_cpp.ll"}});
 
   auto *GlobalDtor =
-      IRDB.getFunction("__psrGlobalDtorsCaller.globals_dtor_1_cpp.ll");
+      IRDB.getFunction(LLVMBasedICFG::GlobalCRuntimeDtorsCallerName.str() +
+                       ".globals_dtor_1_cpp.ll");
 
   ASSERT_NE(nullptr, GlobalDtor);
 

unittests/PhasarLLVM/ControlFlow/LLVMBasedICFGTest.cpp

@@ -83,9 +83,9 @@ TEST(LLVMBasedICFGTest, StaticCallSite_2b) {
   const llvm::Function *FOO = IRDB.getFunctionDefinition("foo");
   const llvm::Function *BAR = IRDB.getFunctionDefinition("bar");
   const llvm::Function *CTOR =
-      IRDB.getFunctionDefinition("__psrCRuntimeGlobalCtorsModel");
+      IRDB.getFunctionDefinition(LLVMBasedICFG::GlobalCRuntimeModelName);
   const llvm::Function *DTOR =
-      IRDB.getFunctionDefinition("__psrCRuntimeGlobalDtorsModel");
+      IRDB.getFunctionDefinition(LLVMBasedICFG::GlobalCRuntimeDtorModelName);
   ASSERT_TRUE(F);
   ASSERT_TRUE(FOO);
   ASSERT_TRUE(BAR);