[wasm] Fix long branches in jiterpreter (dotnet#106030)

* Update enum * Fix branches with immediates
BrzVlad · Aug 7, 2024 · 9fa8fd5 · 9fa8fd5
1 parent 334d57e
commit 9fa8fd5
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Showing 2 changed files with 27 additions and 8 deletions.
diff --git a/src/mono/browser/runtime/jiterpreter-opcodes.ts b/src/mono/browser/runtime/jiterpreter-opcodes.ts
@@ -36,7 +36,6 @@ export const enum MintOpArgType {
  MintOpFloat,
  MintOpDouble,
  MintOpBranch,
- MintOpShortBranch,
  MintOpSwitch,
  MintOpMethodToken,
  MintOpFieldToken,

diff --git a/src/mono/browser/runtime/jiterpreter-trace-generator.ts b/src/mono/browser/runtime/jiterpreter-trace-generator.ts
@@ -2752,6 +2752,21 @@ function append_call_handler_store_ret_ip (
  builder.callHandlerReturnAddresses.push(retIp);
 }
 
+function getBranchImmediate (
+ ip: MintOpcodePtr, opcode: MintOpcode
+): number | undefined {
+ const opArgType = cwraps.mono_jiterp_get_opcode_info(opcode, OpcodeInfoType.OpArgType),
+ payloadOffset = cwraps.mono_jiterp_get_opcode_info(opcode, OpcodeInfoType.Sregs),
+ payloadAddress = <any>ip + 2 + (payloadOffset * 2);
+
+ switch (opArgType) {
+ case MintOpArgType.MintOpShortAndBranch:
+ return getI16(payloadAddress);
+ default:
+ return undefined;
+ }
+}
+
 function getBranchDisplacement (
  ip: MintOpcodePtr, opcode: MintOpcode
 ): number | undefined {
@@ -2785,8 +2800,10 @@ function emit_branch (
  (opcode <= MintOpcode.MINT_BLT_UN_I8_IMM_SP);
 
  const displacement = getBranchDisplacement(ip, opcode);
- if (typeof (displacement) !== "number")
+ if (typeof (displacement) !== "number") {
+ // mono_log_info(`Failed to decode branch displacement for ${getOpcodeName(opcode)}`);
  return false;
+ }
 
  // If the branch is taken we bail out to allow the interpreter to do it.
  // So for brtrue, we want to do 'cond == 0' to produce a bailout only
@@ -2874,9 +2891,6 @@ function emit_branch (
  if (relopbranchTable[opcode] === undefined)
  throw new Error(`Unsupported relop branch opcode: ${getOpcodeName(opcode)}`);
 
- if (cwraps.mono_jiterp_get_opcode_info(opcode, OpcodeInfoType.Length) !== 4)
- throw new Error(`Unsupported long branch opcode: ${getOpcodeName(opcode)}`);
-
  break;
  }
  }
@@ -2920,8 +2934,10 @@ function emit_relop_branch (
  frame: NativePointer, opcode: MintOpcode
 ): boolean {
  const relopBranchInfo = relopbranchTable[opcode];
- if (!relopBranchInfo)
+ if (!relopBranchInfo) {
+ // mono_log_info(`No info for relop branch ${getOpcodeName(opcode)}`);
  return false;
+ }
 
  const relop = Array.isArray(relopBranchInfo)
  ? relopBranchInfo[0]
@@ -2930,8 +2946,10 @@ function emit_relop_branch (
  const relopInfo = binopTable[relop];
  const intrinsicFpBinop = intrinsicFpBinops[relop];
 
- if (!relopInfo && !intrinsicFpBinop)
+ if (!relopInfo && !intrinsicFpBinop) {
+ // mono_log_info(`No info for relop ${getOpcodeName(opcode)} -> ${getOpcodeName(relop)}`);
  return false;
+ }
 
  const operandLoadOp = relopInfo
  ? relopInfo[1]
@@ -2948,11 +2966,13 @@ function emit_relop_branch (
 
  // Compare with immediate
  if (Array.isArray(relopBranchInfo) && relopBranchInfo[1]) {
+ const immediate = getBranchImmediate(ip, opcode);
+ mono_assert(immediate !== undefined, `Failed to decode immediate for branch opcode ${getOpcodeName(opcode)}`);
  // For i8 immediates we need to generate an i64.const even though
  // the immediate is 16 bits, so we store the relevant opcode
  // in the relop branch info table
  builder.appendU8(relopBranchInfo[1]);
- builder.appendLeb(getArgI16(ip, 2));
+ builder.appendLeb(immediate);
  } else
  append_ldloc(builder, getArgU16(ip, 2), operandLoadOp);