Bug 1598631 - Remove JSOP_LABEL. r=tcampbell

This was a hint for Ion compilation that we no longer need after bug 1595476.

Differential Revision: https://phabricator.services.mozilla.com/D54295

--HG--
extra : moz-landing-system : lando

js/src/debugger/Script.cpp

@@ -1502,7 +1502,6 @@ static bool BytecodeIsEffectful(JSOp op) {
     case JSOP_TRY_DESTRUCTURING:
     case JSOP_LINENO:
     case JSOP_JUMPTARGET:
-    case JSOP_LABEL:
     case JSOP_UNDEFINED:
     case JSOP_IFNE:
     case JSOP_IFEQ:
@@ -1706,6 +1705,7 @@ static bool BytecodeIsEffectful(JSOp op) {
     case JSOP_THROWMSG:
     case JSOP_FORCEINTERPRETER:
     case JSOP_UNUSED71:
+    case JSOP_UNUSED106:
     case JSOP_UNUSED120:
     case JSOP_UNUSED149:
     case JSOP_LIMIT:

js/src/frontend/BytecodeEmitter.cpp

@@ -7673,9 +7673,9 @@ MOZ_NEVER_INLINE bool BytecodeEmitter::emitLabeledStatement(
     const LabeledStatement* labeledStmt) {
   RootedAtom name(cx, labeledStmt->label());
   LabelEmitter label(this);
-  if (!label.emitLabel(name)) {
-    return false;
-  }
+
+  label.emitLabel(name);
+
   if (!emitTree(labeledStmt->statement())) {
     return false;
   }

js/src/frontend/LabelEmitter.cpp

@@ -9,43 +9,23 @@
 #include "mozilla/Assertions.h"  // MOZ_ASSERT
 
 #include "frontend/BytecodeEmitter.h"  // BytecodeEmitter
-#include "vm/BytecodeUtil.h"           // SET_CODE_OFFSET
-#include "vm/Opcodes.h"                // JSOP_*
 
 using namespace js;
 using namespace js::frontend;
 
-bool LabelEmitter::emitLabel(HandleAtom name) {
+void LabelEmitter::emitLabel(HandleAtom name) {
   MOZ_ASSERT(state_ == State::Start);
 
-  // Emit a JSOP_LABEL instruction. The operand is the offset to the statement
-  // following the labeled statement. The offset is set in emitEnd().
-  uint32_t index;
-  if (!bce_->makeAtomIndex(name, &index)) {
-    return false;
-  }
-  if (!bce_->emitN(JSOP_LABEL, 4, &top_)) {
-    return false;
-  }
-
   controlInfo_.emplace(bce_, name, bce_->bytecodeSection().offset());
 
 #ifdef DEBUG
   state_ = State::Label;
 #endif
-  return true;
 }
 
 bool LabelEmitter::emitEnd() {
   MOZ_ASSERT(state_ == State::Label);
 
-  // Patch the JSOP_LABEL offset.
-  jsbytecode* labelpc = bce_->bytecodeSection().code(top_);
-  BytecodeOffsetDiff offset =
-      bce_->bytecodeSection().lastNonJumpTargetOffset() - top_;
-  MOZ_ASSERT(*labelpc == JSOP_LABEL);
-  SET_CODE_OFFSET(labelpc, offset.value());
-
   // Patch the break/continue to this label.
   if (!controlInfo_->patchBreaks(bce_)) {
     return false;

js/src/frontend/LabelEmitter.h

@@ -33,9 +33,6 @@ struct BytecodeEmitter;
 class MOZ_STACK_CLASS LabelEmitter {
   BytecodeEmitter* bce_;
 
-  // The offset of the JSOP_LABEL.
-  BytecodeOffset top_;
-
   mozilla::Maybe<LabelControl> controlInfo_;
 
 #ifdef DEBUG
@@ -60,7 +57,7 @@ class MOZ_STACK_CLASS LabelEmitter {
  public:
   explicit LabelEmitter(BytecodeEmitter* bce) : bce_(bce) {}
 
-  MOZ_MUST_USE bool emitLabel(HandleAtom name);
+  void emitLabel(HandleAtom name);
   MOZ_MUST_USE bool emitEnd();
 };
 

js/src/jit/BaselineCodeGen.cpp

@@ -1726,11 +1726,6 @@ bool BaselineCodeGen<Handler>::emit_JSOP_TRY_DESTRUCTURING() {
   return true;
 }
 
-template <typename Handler>
-bool BaselineCodeGen<Handler>::emit_JSOP_LABEL() {
-  return true;
-}
-
 template <typename Handler>
 bool BaselineCodeGen<Handler>::emit_JSOP_POP() {
   frame.pop();
@@ -6927,6 +6922,7 @@ MethodStatus BaselineCompiler::emitBody() {
       case JSOP_FORCEINTERPRETER:
         // Caller must have checked script->hasForceInterpreterOp().
       case JSOP_UNUSED71:
+      case JSOP_UNUSED106:
       case JSOP_UNUSED120:
       case JSOP_UNUSED149:
       case JSOP_LIMIT:

js/src/jit/BaselineCodeGen.h

@@ -22,7 +22,6 @@ namespace jit {
 #define OPCODE_LIST(_)              \
   _(JSOP_NOP)                       \
   _(JSOP_NOP_DESTRUCTURING)         \
-  _(JSOP_LABEL)                     \
   _(JSOP_ITERNEXT)                  \
   _(JSOP_POP)                       \
   _(JSOP_POPN)                      \

js/src/jit/IonBuilder.cpp

@@ -1993,7 +1993,6 @@ AbortReasonOr<Ok> IonBuilder::inspectOpcode(JSOp op, bool* restarted) {
     case JSOP_NOP_DESTRUCTURING:
     case JSOP_TRY_DESTRUCTURING:
     case JSOP_LINENO:
-    case JSOP_LABEL:
       return Ok();
 
     case JSOP_NOP: {
@@ -2693,6 +2692,7 @@ AbortReasonOr<Ok> IonBuilder::inspectOpcode(JSOp op, bool* restarted) {
       break;
 
     case JSOP_UNUSED71:
+    case JSOP_UNUSED106:
     case JSOP_UNUSED120:
     case JSOP_UNUSED149:
     case JSOP_LIMIT:

js/src/vm/BytecodeUtil.cpp

@@ -1432,14 +1432,6 @@ static unsigned Disassemble1(JSContext* cx, HandleScript script, jsbytecode* pc,
       break;
     }
 
-    case JOF_CODE_OFFSET: {
-      ptrdiff_t off = GET_CODE_OFFSET(pc);
-      if (!sp->jsprintf(" %u (%+d)", unsigned(loc + int(off)), int(off))) {
-        return 0;
-      }
-      break;
-    }
-
     case JOF_SCOPE: {
       RootedScope scope(cx, script->getScope(GET_UINT32_INDEX(pc)));
       UniqueChars bytes;

js/src/vm/BytecodeUtil.h

@@ -59,10 +59,9 @@ enum {
   JOF_REGEXP = 16,      /* uint32_t regexp index */
   JOF_DOUBLE = 17,      /* inline DoubleValue */
   JOF_SCOPE = 18,       /* uint32_t scope index */
-  JOF_CODE_OFFSET = 19, /* int32_t bytecode offset */
-  JOF_ICINDEX = 20,     /* uint32_t IC index */
-  JOF_LOOPENTRY = 21,   /* JSOP_LOOPENTRY, combines JOF_ICINDEX and JOF_UINT8 */
-  JOF_BIGINT = 22,      /* uint32_t index for BigInt value */
+  JOF_ICINDEX = 19,     /* uint32_t IC index */
+  JOF_LOOPENTRY = 20,   /* JSOP_LOOPENTRY, combines JOF_ICINDEX and JOF_UINT8 */
+  JOF_BIGINT = 21,      /* uint32_t index for BigInt value */
   JOF_TYPEMASK = 0x001f, /* mask for above immediate types */
 
   JOF_NAME = 1 << 5,     /* name operation */
@@ -191,14 +190,6 @@ static MOZ_ALWAYS_INLINE void SET_JUMP_OFFSET(jsbytecode* pc, int32_t off) {
   SET_INT32(pc, off);
 }
 
-static MOZ_ALWAYS_INLINE int32_t GET_CODE_OFFSET(jsbytecode* pc) {
-  return GET_INT32(pc);
-}
-
-static MOZ_ALWAYS_INLINE void SET_CODE_OFFSET(jsbytecode* pc, int32_t off) {
-  SET_INT32(pc, off);
-}
-
 static const unsigned UINT32_INDEX_LEN = 4;
 
 static MOZ_ALWAYS_INLINE uint32_t GET_UINT32_INDEX(const jsbytecode* pc) {

js/src/vm/Interpreter.cpp

@@ -1977,6 +1977,7 @@ static MOZ_NEVER_INLINE JS_HAZ_JSNATIVE_CALLER bool Interpret(JSContext* cx,
     CASE(JSOP_NOP_DESTRUCTURING)
     CASE(JSOP_TRY_DESTRUCTURING)
     CASE(JSOP_UNUSED71)
+    CASE(JSOP_UNUSED106)
     CASE(JSOP_UNUSED120)
     CASE(JSOP_UNUSED149)
     CASE(JSOP_TRY) {
@@ -1991,9 +1992,6 @@ static MOZ_NEVER_INLINE JS_HAZ_JSNATIVE_CALLER bool Interpret(JSContext* cx,
       ADVANCE_AND_DISPATCH(JSOP_JUMPTARGET_LENGTH);
     }
 
-    CASE(JSOP_LABEL)
-    END_CASE(JSOP_LABEL)
-
     CASE(JSOP_LOOPENTRY) {
       COUNT_COVERAGE();
       // Attempt on-stack replacement into the Baseline Interpreter.

js/src/vm/Opcodes.h

@@ -1076,17 +1076,8 @@
      */ \
     MACRO(JSOP_STRICTSETPROP_SUPER, 105, "strictsetprop-super", NULL, 5, 3, 1, JOF_ATOM|JOF_PROP|JOF_PROPSET|JOF_DETECTING|JOF_CHECKSTRICT) \
     /*
-     * This opcode precedes every labeled statement. It's a no-op.
-     *
-     * 'offset' is the offset to the next instruction after this statement, the
-     * one 'break LABEL;' would jump to. IonMonkey uses this.
-     *
-     *   Category: Statements
-     *   Type: Jumps
-     *   Operands: int32_t offset
-     *   Stack: =>
      */ \
-    MACRO(JSOP_LABEL, 106, "label", NULL, 5, 0, 0, JOF_CODE_OFFSET) \
+    MACRO(JSOP_UNUSED106, 106, "unused", NULL, 1, 0, 0, JOF_BYTE) \
     /*
      * Pops the top three values on the stack as 'val', 'obj' and 'receiver',
      * and performs 'obj.prop = val', pushing 'val' back onto the stack.