[mono][interp] Completely remove short branches

They don't seem to have any benefit at the expense of a lot of code and added complexity.

Author: BrzVlad

src/mono/browser/runtime/jiterpreter-trace-generator.ts

@@ -218,7 +218,6 @@ export function generateBackwardBranchTable (
 
         switch (opcode) {
             case MintOpcode.MINT_CALL_HANDLER:
-            case MintOpcode.MINT_CALL_HANDLER_S:
                 // While this formally isn't a backward branch target, we want to record
                 //  the offset of its following instruction so that the jiterpreter knows
                 //  to generate the necessary dispatch code to enable branching back to it.
@@ -506,21 +505,15 @@ export function generateWasmBody (
             }
 
             // Other conditional branch types are handled by the relop table.
-            case MintOpcode.MINT_BRFALSE_I4_S:
-            case MintOpcode.MINT_BRTRUE_I4_S:
             case MintOpcode.MINT_BRFALSE_I4_SP:
             case MintOpcode.MINT_BRTRUE_I4_SP:
-            case MintOpcode.MINT_BRFALSE_I8_S:
-            case MintOpcode.MINT_BRTRUE_I8_S:
                 if (!emit_branch(builder, ip, frame, opcode))
                     ip = abort;
                 else
                     isConditionallyExecuted = true;
                 break;
 
-            case MintOpcode.MINT_BR_S:
             case MintOpcode.MINT_CALL_HANDLER:
-            case MintOpcode.MINT_CALL_HANDLER_S:
                 if (!emit_branch(builder, ip, frame, opcode))
                     ip = abort;
                 else {
@@ -1293,7 +1286,6 @@ export function generateWasmBody (
             // These are generated in place of regular LEAVEs inside of the body of a catch clause.
             // We can safely assume that during normal execution, catch clauses won't be running.
             case MintOpcode.MINT_LEAVE_CHECK:
-            case MintOpcode.MINT_LEAVE_S_CHECK:
                 append_bailout(builder, ip, BailoutReason.LeaveCheck);
                 pruneOpcodes = true;
                 break;
@@ -2745,8 +2737,7 @@ function append_call_handler_store_ret_ip (
     builder: WasmBuilder, ip: MintOpcodePtr,
     frame: NativePointer, opcode: MintOpcode
 ) {
-    const shortOffset = (opcode === MintOpcode.MINT_CALL_HANDLER_S),
-        retIp = shortOffset ? <any>ip + (3 * 2) : <any>ip + (4 * 2),
+    const retIp = <any>ip + (4 * 2),
         clauseIndex = getU16(retIp - 2),
         clauseDataOffset = get_imethod_clause_data_offset(frame, clauseIndex);
 
@@ -2773,9 +2764,6 @@ function getBranchDisplacement (
         case MintOpArgType.MintOpBranch:
             result = getI32_unaligned(payloadAddress);
             break;
-        case MintOpArgType.MintOpShortBranch:
-            result = getI16(payloadAddress);
-            break;
         case MintOpArgType.MintOpShortAndBranch:
             result = getI32_unaligned(payloadAddress + 2);
             break;
@@ -2808,11 +2796,8 @@ function emit_branch (
     //  branch target (if possible), bailing out at the end otherwise
     switch (opcode) {
         case MintOpcode.MINT_CALL_HANDLER:
-        case MintOpcode.MINT_CALL_HANDLER_S:
-        case MintOpcode.MINT_BR:
-        case MintOpcode.MINT_BR_S: {
-            const isCallHandler = (opcode === MintOpcode.MINT_CALL_HANDLER) ||
-                (opcode === MintOpcode.MINT_CALL_HANDLER_S);
+        case MintOpcode.MINT_BR: {
+            const isCallHandler = opcode === MintOpcode.MINT_CALL_HANDLER;
 
             const destination = <any>ip + (displacement * 2);