Reland [Clang][analyzer] replace Stmt* with ConstCFGElement in SymbolConjured (#137355)

Closes #57270.

This PR changes the `Stmt *` field in `SymbolConjured` with
`CFGBlock::ConstCFGElementRef`. The motivation is that, when conjuring a
symbol, there might not always be a statement available, causing
information to be lost for conjured symbols, whereas the CFGElementRef
can always be provided at the callsite.

Following the idea, this PR changes callsites of functions to create
conjured symbols, and replaces them with appropriate `CFGElementRef`s.

There is a caveat at loop widening, where the correct location is the
CFG terminator (which is not an element and does not have a ref). In
this case, the first element in the block is passed as a location.

Previous PR #128251, Reverted at #137304.

1 files changed, 26 insertions, 20 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index f58d31ba..23876d5 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -5841,16 +5841,17 @@ static void print_construction_context(raw_ostream &OS,
 }
 
 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
-                       const CFGElement &E);
+                       const CFGElement &E, bool TerminateWithNewLine = true);
 
-void CFGElement::dumpToStream(llvm::raw_ostream &OS) const {
+void CFGElement::dumpToStream(llvm::raw_ostream &OS,
+                              bool TerminateWithNewLine) const {
   LangOptions LangOpts;
   StmtPrinterHelper Helper(nullptr, LangOpts);
-  print_elem(OS, Helper, *this);
+  print_elem(OS, Helper, *this, TerminateWithNewLine);
 }
 
 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
-                       const CFGElement &E) {
+                       const CFGElement &E, bool TerminateWithNewLine) {
   switch (E.getKind()) {
   case CFGElement::Kind::Statement:
   case CFGElement::Kind::CXXRecordTypedCall:
@@ -5867,7 +5868,9 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
       if (Children.begin() != Children.end()) {
         OS << "({ ... ; ";
         Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
-        OS << " })\n";
+        OS << " })";
+        if (TerminateWithNewLine)
+          OS << '\n';
         return;
       }
     }
@@ -5876,7 +5879,8 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
       if (B->getOpcode() == BO_Comma) {
         OS << "... , ";
         Helper.handledStmt(B->getRHS(),OS);
-        OS << '\n';
+        if (TerminateWithNewLine)
+          OS << '\n';
         return;
       }
     }
@@ -5904,15 +5908,14 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
     }
 
     // Expressions need a newline.
-    if (isa<Expr>(S))
+    if (isa<Expr>(S) && TerminateWithNewLine)
       OS << '\n';
 
-    break;
+    return;
   }
 
   case CFGElement::Kind::Initializer:
     print_initializer(OS, Helper, E.castAs<CFGInitializer>().getInitializer());
-    OS << '\n';
     break;
 
   case CFGElement::Kind::AutomaticObjectDtor: {
@@ -5926,43 +5929,44 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
 
     OS << ".~";
     T.getUnqualifiedType().print(OS, PrintingPolicy(Helper.getLangOpts()));
-    OS << "() (Implicit destructor)\n";
+    OS << "() (Implicit destructor)";
     break;
   }
 
   case CFGElement::Kind::CleanupFunction:
     OS << "CleanupFunction ("
-       << E.castAs<CFGCleanupFunction>().getFunctionDecl()->getName() << ")\n";
+       << E.castAs<CFGCleanupFunction>().getFunctionDecl()->getName() << ")";
     break;
 
   case CFGElement::Kind::LifetimeEnds:
     Helper.handleDecl(E.castAs<CFGLifetimeEnds>().getVarDecl(), OS);
-    OS << " (Lifetime ends)\n";
+    OS << " (Lifetime ends)";
     break;
 
   case CFGElement::Kind::LoopExit:
-    OS << E.castAs<CFGLoopExit>().getLoopStmt()->getStmtClassName() << " (LoopExit)\n";
+    OS << E.castAs<CFGLoopExit>().getLoopStmt()->getStmtClassName()
+       << " (LoopExit)";
     break;
 
   case CFGElement::Kind::ScopeBegin:
     OS << "CFGScopeBegin(";
     if (const VarDecl *VD = E.castAs<CFGScopeBegin>().getVarDecl())
       OS << VD->getQualifiedNameAsString();
-    OS << ")\n";
+    OS << ")";
     break;
 
   case CFGElement::Kind::ScopeEnd:
     OS << "CFGScopeEnd(";
     if (const VarDecl *VD = E.castAs<CFGScopeEnd>().getVarDecl())
       OS << VD->getQualifiedNameAsString();
-    OS << ")\n";
+    OS << ")";
     break;
 
   case CFGElement::Kind::NewAllocator:
     OS << "CFGNewAllocator(";
     if (const CXXNewExpr *AllocExpr = E.castAs<CFGNewAllocator>().getAllocatorExpr())
       AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
-    OS << ")\n";
+    OS << ")";
     break;
 
   case CFGElement::Kind::DeleteDtor: {
@@ -5974,14 +5978,14 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
         const_cast<CXXDeleteExpr*>(DE.getDeleteExpr());
     Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
     OS << "->~" << RD->getName().str() << "()";
-    OS << " (Implicit destructor)\n";
+    OS << " (Implicit destructor)";
     break;
   }
 
   case CFGElement::Kind::BaseDtor: {
     const CXXBaseSpecifier *BS = E.castAs<CFGBaseDtor>().getBaseSpecifier();
     OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
-    OS << " (Base object destructor)\n";
+    OS << " (Base object destructor)";
     break;
   }
 
@@ -5990,7 +5994,7 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
     const Type *T = FD->getType()->getBaseElementTypeUnsafe();
     OS << "this->" << FD->getName();
     OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
-    OS << " (Member object destructor)\n";
+    OS << " (Member object destructor)";
     break;
   }
 
@@ -5999,10 +6003,12 @@ static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
         E.castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
     OS << "~";
     BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
-    OS << "() (Temporary object destructor)\n";
+    OS << "() (Temporary object destructor)";
     break;
   }
   }
+  if (TerminateWithNewLine)
+    OS << '\n';
 }
 
 static void print_block(raw_ostream &OS, const CFG* cfg,