96   // For each BLOCK|LOOP|TRY, the corresponding END_(BLOCK|LOOP|TRY) or DELEGATE
99   // For each END_(BLOCK|LOOP|TRY) or DELEGATE, the corresponding
120   // Before running rewriteDepthImmediates function, 'delegate' has a BB as its
122   // used for the operand when 'delegate' needs to rethrow to the caller. This
225 // When 'End' is not an 'end_try' but 'delegate, EHPad is nullptr.
712       // We started from an EH pad, so the end marker cannot be a delegate  in removeUnnecessaryInstrs()
713       assert(EndTry->getOpcode() != WebAssembly::DELEGATE);  in removeUnnecessaryInstrs()
759       if (EndTry->getOpcode() == WebAssembly::DELEGATE)  in removeUnnecessaryInstrs()
844 // Wrap the given range of instruction with try-delegate. RangeBegin and
876   // Create a BB to insert the 'delegate' instruction.  in addTryDelegate()
878   // If the destination of 'delegate' is not the caller, adds the destination to  in addTryDelegate()
886     // delegate BB after the current BB.  in addTryDelegate()
892     // put the 'delegate' BB in between. We normally create a split BB and make  in addTryDelegate()
911       // BB into two and insert the delegate BB in between.  in addTryDelegate()
921       //   delegate  in addTryDelegate()
941       //   delegate  in addTryDelegate()
960   // Add 'delegate' instruction in the delegate BB created above.  in addTryDelegate()
961   MachineInstr *Delegate = BuildMI(DelegateBB, RangeEnd->getDebugLoc(),  in addTryDelegate()  local
962                                    TII.get(WebAssembly::DELEGATE))  in addTryDelegate()
964   registerTryScope(Try, Delegate, nullptr);  in addTryDelegate()
971   // We use the 'delegate' instruction to fix the unwind mismatches. 'delegate'  in fixCallUnwindMismatches()
973   // only 'catch' but all block-like structures including another 'delegate',  in fixCallUnwindMismatches()
975   // 'catch', it will delegate the exception to that catch. It is being  in fixCallUnwindMismatches()
976   // discussed how to define the semantics when 'delegate''s target is a non-try  in fixCallUnwindMismatches()
979   // such code. The example below illustrates where the 'delegate' instruction  in fixCallUnwindMismatches()
980   // in the middle will delegate the exception to, depending on the value of N.  in fixCallUnwindMismatches()
987   //         delegate N    ;; Where will this delegate to?  in fixCallUnwindMismatches()
991   //   delegate            ;; N == 2  in fixCallUnwindMismatches()
1026   // call with an inner try-delegate that rethrows the exception to the right  in fixCallUnwindMismatches()
1034   //     delegate 1 (bb3)  ;; (new)  in fixCallUnwindMismatches()
1066   // case 'delegate's immediate argument is the number of block depths + 1,  in fixCallUnwindMismatches()
1072   //   delegate 1 (caller)  ;; (new)  in fixCallUnwindMismatches()
1077   // Before rewriteDepthImmediates, delegate's argument is a BB. In case of the  in fixCallUnwindMismatches()
1082   // can be wrapped together in one nested try-delegate scope. (In 1, this  in fixCallUnwindMismatches()
1233       // are going to wrap the invoke with try-delegate, making the 'delegate'  in fixCallUnwindMismatches()
1278   // try-delegate, so we wrap the whole try-catch-end with a try-delegate and  in fixCatchUnwindMismatches()
1287   //   delegate 1 (caller)     ;; (new)  in fixCatchUnwindMismatches()
1303       else if (MI.getOpcode() == WebAssembly::DELEGATE)  in fixCatchUnwindMismatches()
1364   // Adding a try-delegate wrapping an existing try-catch-end can make existing  in fixCatchUnwindMismatches()
1381   // this with a try-delegate. Then this becomes:  in fixCatchUnwindMismatches()
1396   //     delegate  ;; (new instruction)  in fixCatchUnwindMismatches()
1403   // 'end_try' and 'end_block' and the BB is split to insert a 'delegate', we  in fixCatchUnwindMismatches()
1405   // 'end_try' BB but the new 'end_block' BB. There can be multiple 'delegate's  in fixCatchUnwindMismatches()
1451       case WebAssembly::DELEGATE:  in recalculateScopeTops()
1508       case WebAssembly::DELEGATE:  in fixEndsAtEndOfFunction()
1581   // Delegate's destination is either a catch or a another delegate BB. When the  in getDelegateDepth()
1582   // destination is another delegate, we can compute the argument in the same  in getDelegateDepth()
1583   // way as branches, because the target delegate BB only contains the single  in getDelegateDepth()
1584   // delegate instruction.  in getDelegateDepth()
1585   if (!MBB->isEHPad()) // Target is a delegate BB  in getDelegateDepth()
1588   // When the delegate's destination is a catch BB, we need to use its  in getDelegateDepth()
1600   // fine, but delegate has to exactly target the correct try.  in getDelegateDepth()
1608   assert(Depth < Stack.size() && "Delegate destination should be in scope");  in getDelegateDepth()
1665               if (MI.getOpcode() == WebAssembly::DELEGATE)  in rewriteDepthImmediates()
1679         if (MI.getOpcode() == WebAssembly::DELEGATE)  in rewriteDepthImmediates()