[CIR][CIRGen][Exceptions][NFC] Reuse lexical scope instead of custom RAII

Author: bcardosolopes

clang/lib/CIR/CodeGen/CIRGenCall.cpp

@@ -366,13 +366,12 @@ buildCallLikeOp(CIRGenFunction &CGF, mlir::Location callLoc,
   auto &builder = CGF.getBuilder();
 
   if (InvokeDest) {
+    auto addr = CGF.currLexScope->getExceptionInfo().addr;
     if (indirectFuncTy)
       return builder.create<mlir::cir::TryCallOp>(
-          callLoc, CGF.currExceptionInfo.exceptionAddr, indirectFuncVal,
-          indirectFuncTy, CIRCallArgs);
-    return builder.create<mlir::cir::TryCallOp>(
-        callLoc, directFuncOp, CGF.currExceptionInfo.exceptionAddr,
-        CIRCallArgs);
+          callLoc, addr, indirectFuncVal, indirectFuncTy, CIRCallArgs);
+    return builder.create<mlir::cir::TryCallOp>(callLoc, directFuncOp, addr,
+                                                CIRCallArgs);
   }
 
   if (indirectFuncTy)

clang/lib/CIR/CodeGen/CIRGenException.cpp

@@ -256,7 +256,7 @@ mlir::Block *CIRGenFunction::getEHResumeBlock(bool isCleanup) {
   // Just like some other try/catch related logic: return the basic block
   // pointer but only use it to denote we're tracking things, but there
   // shouldn't be any changes to that block after work done in this function.
-  auto catchOp = currExceptionInfo.catchOp;
+  auto catchOp = currLexScope->getExceptionInfo().catchOp;
   assert(catchOp.getNumRegions() && "expected at least one region");
   auto &fallbackRegion = catchOp.getRegion(catchOp.getNumRegions() - 1);
 
@@ -379,7 +379,7 @@ CIRGenFunction::buildCXXTryStmtUnderScope(const CXXTryStmt &S) {
                                           getBuilder().getInsertionBlock()};
 
     {
-      ExceptionInfoRAIIObject ehx{*this, {exceptionInfoInsideTry, catchOp}};
+      lexScope.setExceptionInfo({exceptionInfoInsideTry, catchOp});
       // Attach the basic blocks for the catchOp regions into ScopeCatch
       // info.
       enterCXXTryStmt(S, catchOp);
@@ -393,7 +393,7 @@ CIRGenFunction::buildCXXTryStmtUnderScope(const CXXTryStmt &S) {
     }
 
     {
-      ExceptionInfoRAIIObject ehx{*this, {tryScope->getResult(0), catchOp}};
+      lexScope.setExceptionInfo({tryScope->getResult(0), catchOp});
       // Emit catch clauses.
       exitCXXTryStmt(S);
     }
@@ -633,7 +633,7 @@ mlir::Operation *CIRGenFunction::buildLandingPad() {
   // If there's an existing CatchOp, it means we got a `cir.try` scope
   // that leads to this "landing pad" creation site. Otherwise, exceptions
   // are enabled but a throwing function is called anyways.
-  auto catchOp = currExceptionInfo.catchOp;
+  auto catchOp = currLexScope->getExceptionInfo().catchOp;
   if (!catchOp) {
     llvm_unreachable("NYI");
   }

clang/lib/CIR/CodeGen/CIRGenFunction.h

@@ -312,26 +312,9 @@ class CIRGenFunction : public CIRGenTypeCache {
   /// Try/Catch: calls within try statements need to refer to local
   /// allocas for the exception info
   struct CIRExceptionInfo {
-    mlir::Value exceptionAddr{};
+    mlir::Value addr{};
     mlir::cir::CatchOp catchOp{};
   };
-  CIRExceptionInfo currExceptionInfo{};
-  class ExceptionInfoRAIIObject {
-    CIRGenFunction &P;
-    CIRExceptionInfo OldVal{};
-
-  public:
-    ExceptionInfoRAIIObject(CIRGenFunction &p, CIRExceptionInfo info) : P(p) {
-      if (P.currExceptionInfo.exceptionAddr)
-        OldVal = P.currExceptionInfo;
-      P.currExceptionInfo = info;
-    }
-
-    /// Can be used to restore the state early, before the dtor
-    /// is run.
-    void restore() { P.currExceptionInfo = OldVal; }
-    ~ExceptionInfoRAIIObject() { restore(); }
-  };
 
   enum class EvaluationOrder {
     ///! No langauge constraints on evaluation order.
@@ -1773,6 +1756,9 @@ class CIRGenFunction : public CIRGenTypeCache {
 
     LexicalScope *ParentScope = nullptr;
 
+    // If there's exception information for this scope, store it.
+    CIRExceptionInfo exInfo{};
+
     // FIXME: perhaps we can use some info encoded in operations.
     enum Kind {
       Regular, // cir.if, cir.scope, if_regions
@@ -1873,6 +1859,12 @@ class CIRGenFunction : public CIRGenTypeCache {
     // Labels solved inside this scope.
     llvm::SmallPtrSet<const clang::LabelDecl *, 4> SolvedLabels;
 
+    // ---
+    // Exception handling
+    // ---
+    CIRExceptionInfo &getExceptionInfo() { return exInfo; }
+    void setExceptionInfo(const CIRExceptionInfo &info) { exInfo = info; }
+
     // ---
     // Return handling
     // ---

clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp

@@ -667,7 +667,7 @@ static mlir::Value CallBeginCatch(CIRGenFunction &CGF, mlir::Value Exn,
 static void InitCatchParam(CIRGenFunction &CGF, const VarDecl &CatchParam,
                            Address ParamAddr, SourceLocation Loc) {
   // Load the exception from where the landing pad saved it.
-  auto Exn = CGF.currExceptionInfo.exceptionAddr;
+  auto Exn = CGF.currLexScope->getExceptionInfo().addr;
 
   CanQualType CatchType =
       CGF.CGM.getASTContext().getCanonicalType(CatchParam.getType());
@@ -771,7 +771,7 @@ void CIRGenItaniumCXXABI::emitBeginCatch(CIRGenFunction &CGF,
 
   VarDecl *CatchParam = S->getExceptionDecl();
   if (!CatchParam) {
-    auto Exn = CGF.currExceptionInfo.exceptionAddr;
+    auto Exn = CGF.currLexScope->getExceptionInfo().addr;
     CallBeginCatch(CGF, Exn, CGF.getBuilder().getVoidPtrTy(), true);
     return;
   }