1 files changed, 88 insertions, 2 deletions
diff --git a/clang/lib/CIR/CodeGen/EHScopeStack.h b/clang/lib/CIR/CodeGen/EHScopeStack.h
index 67a72f5..4198c23 100644
--- a/clang/lib/CIR/CodeGen/EHScopeStack.h
+++ b/clang/lib/CIR/CodeGen/EHScopeStack.h
@@ -18,12 +18,38 @@
 #ifndef CLANG_LIB_CIR_CODEGEN_EHSCOPESTACK_H
 #define CLANG_LIB_CIR_CODEGEN_EHSCOPESTACK_H
 
+#include "clang/CIR/Dialect/IR/CIRDialect.h"
 #include "llvm/ADT/SmallVector.h"
 
 namespace clang::CIRGen {
 
 class CIRGenFunction;
 
+/// A branch fixup.  These are required when emitting a goto to a
+/// label which hasn't been emitted yet.  The goto is optimistically
+/// emitted as a branch to the basic block for the label, and (if it
+/// occurs in a scope with non-trivial cleanups) a fixup is added to
+/// the innermost cleanup.  When a (normal) cleanup is popped, any
+/// unresolved fixups in that scope are threaded through the cleanup.
+struct BranchFixup {
+  /// The block containing the terminator which needs to be modified
+  /// into a switch if this fixup is resolved into the current scope.
+  /// If null, LatestBranch points directly to the destination.
+  mlir::Block *optimisticBranchBlock = nullptr;
+
+  /// The ultimate destination of the branch.
+  ///
+  /// This can be set to null to indicate that this fixup was
+  /// successfully resolved.
+  mlir::Block *destination = nullptr;
+
+  /// The destination index value.
+  unsigned destinationIndex = 0;
+
+  /// The initial branch of the fixup.
+  cir::BrOp initialBranch = {};
+};
+
 enum CleanupKind : unsigned {
   /// Denotes a cleanup that should run when a scope is exited using exceptional
   /// control flow (a throw statement leading to stack unwinding, ).
@@ -126,9 +152,31 @@ private:
   /// The first valid entry in the buffer.
   char *startOfData = nullptr;
 
+  /// The innermost normal cleanup on the stack.
+  stable_iterator innermostNormalCleanup = stable_end();
+
   /// The CGF this Stack belong to
   CIRGenFunction *cgf = nullptr;
 
+  /// The current set of branch fixups.  A branch fixup is a jump to
+  /// an as-yet unemitted label, i.e. a label for which we don't yet
+  /// know the EH stack depth.  Whenever we pop a cleanup, we have
+  /// to thread all the current branch fixups through it.
+  ///
+  /// Fixups are recorded as the Use of the respective branch or
+  /// switch statement.  The use points to the final destination.
+  /// When popping out of a cleanup, these uses are threaded through
+  /// the cleanup and adjusted to point to the new cleanup.
+  ///
+  /// Note that branches are allowed to jump into protected scopes
+  /// in certain situations;  e.g. the following code is legal:
+  ///     struct A { ~A(); }; // trivial ctor, non-trivial dtor
+  ///     goto foo;
+  ///     A a;
+  ///    foo:
+  ///     bar();
+  llvm::SmallVector<BranchFixup> branchFixups;
+
   // This class uses a custom allocator for maximum efficiency because cleanups
   // are allocated and freed very frequently. It's basically a bump pointer
   // allocator, but we can't use LLVM's BumpPtrAllocator because we use offsets
@@ -155,9 +203,29 @@ public:
   /// Pops a cleanup scope off the stack.  This is private to CIRGenCleanup.cpp.
   void popCleanup();
 
+  /// Push a set of catch handlers on the stack.  The catch is
+  /// uninitialized and will need to have the given number of handlers
+  /// set on it.
+  class EHCatchScope *pushCatch(unsigned numHandlers);
+
+  /// Pops a catch scope off the stack. This is private to CIRGenException.cpp.
+  void popCatch();
+
   /// Determines whether the exception-scopes stack is empty.
   bool empty() const { return startOfData == endOfBuffer; }
 
+  /// Determines whether there are any normal cleanups on the stack.
+  bool hasNormalCleanups() const {
+    return innermostNormalCleanup != stable_end();
+  }
+
+  /// Returns the innermost normal cleanup on the stack, or
+  /// stable_end() if there are no normal cleanups.
+  stable_iterator getInnermostNormalCleanup() const {
+    return innermostNormalCleanup;
+  }
+  stable_iterator getInnermostActiveNormalCleanup() const;
+
   /// An unstable reference to a scope-stack depth.  Invalidated by
   /// pushes but not pops.
   class iterator;
@@ -172,12 +240,30 @@ public:
     return stable_iterator(endOfBuffer - startOfData);
   }
 
+  /// Create a stable reference to the bottom of the EH stack.
+  static stable_iterator stable_end() { return stable_iterator(0); }
+
   /// Turn a stable reference to a scope depth into a unstable pointer
   /// to the EH stack.
   iterator find(stable_iterator savePoint) const;
 
-  /// Create a stable reference to the bottom of the EH stack.
-  static stable_iterator stable_end() { return stable_iterator(0); }
+  /// Add a branch fixup to the current cleanup scope.
+  BranchFixup &addBranchFixup() {
+    assert(hasNormalCleanups() && "adding fixup in scope without cleanups");
+    branchFixups.push_back(BranchFixup());
+    return branchFixups.back();
+  }
+
+  unsigned getNumBranchFixups() const { return branchFixups.size(); }
+  BranchFixup &getBranchFixup(unsigned i) {
+    assert(i < getNumBranchFixups());
+    return branchFixups[i];
+  }
+
+  /// Pops lazily-removed fixups from the end of the list.  This
+  /// should only be called by procedures which have just popped a
+  /// cleanup or resolved one or more fixups.
+  void popNullFixups();
 };
 
 } // namespace clang::CIRGen