[mips][regexp] Always pass the isolate to CaseInsensitiveCompareUC16

Port d303f4fb https://crrev.com/c/2081816

Original Commit Message:

  In the past we've used the isolate argument to signal whether we were
  in unicode mode (nullptr) or not (the real isolate). This is no longer
  needed, and in fact breaks no-i18n mode which always expects to have a
  real isolate.

Change-Id: I90a69a38cb4e74da46b3030843bc84d6d53571c5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2082932
Auto-Submit: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66549}

src/regexp/mips/regexp-macro-assembler-mips.cc

@@ -223,9 +223,8 @@ void RegExpMacroAssemblerMIPS::CheckGreedyLoop(Label* on_equal) {
   BranchOrBacktrack(on_equal, eq, current_input_offset(), Operand(a0));
 }
 
-
 void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
-    int start_reg, bool read_backward, bool unicode, Label* on_no_match) {
+    int start_reg, bool read_backward, Label* on_no_match) {
   Label fallthrough;
   __ lw(a0, register_location(start_reg));  // Index of start of capture.
   __ lw(a1, register_location(start_reg + 1));  // Index of end of capture.
@@ -320,7 +319,7 @@ void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
     //   a0: Address byte_offset1 - Address captured substring's start.
     //   a1: Address byte_offset2 - Address of current character position.
     //   a2: size_t byte_length - length of capture in bytes(!).
-    //   a3: Isolate* isolate or 0 if unicode flag.
+    //   a3: Isolate* isolate.
 
     // Address of start of capture.
     __ Addu(a0, a0, Operand(end_of_input_address()));
@@ -334,14 +333,7 @@ void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
       __ Subu(a1, a1, Operand(s3));
     }
     // Isolate.
-#ifdef V8_INTL_SUPPORT
-    if (unicode) {
-      __ mov(a3, zero_reg);
-    } else  // NOLINT
-#endif      // V8_INTL_SUPPORT
-    {
-      __ li(a3, Operand(ExternalReference::isolate_address(masm_->isolate())));
-    }
+    __ li(a3, Operand(ExternalReference::isolate_address(masm_->isolate())));
 
     {
       AllowExternalCallThatCantCauseGC scope(masm_);
@@ -368,7 +360,6 @@ void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
   __ bind(&fallthrough);
 }
 
-
 void RegExpMacroAssemblerMIPS::CheckNotBackReference(int start_reg,
                                                      bool read_backward,
                                                      Label* on_no_match) {

src/regexp/mips/regexp-macro-assembler-mips.h

@@ -37,7 +37,7 @@ class V8_EXPORT_PRIVATE RegExpMacroAssemblerMIPS
   virtual void CheckNotBackReference(int start_reg, bool read_backward,
                                      Label* on_no_match);
   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
-                                               bool read_backward, bool unicode,
+                                               bool read_backward,
                                                Label* on_no_match);
   virtual void CheckNotCharacter(uint32_t c, Label* on_not_equal);
   virtual void CheckNotCharacterAfterAnd(uint32_t c,

src/regexp/mips64/regexp-macro-assembler-mips64.cc

@@ -259,9 +259,8 @@ void RegExpMacroAssemblerMIPS::CheckGreedyLoop(Label* on_equal) {
   BranchOrBacktrack(on_equal, eq, current_input_offset(), Operand(a0));
 }
 
-
 void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
-    int start_reg, bool read_backward, bool unicode, Label* on_no_match) {
+    int start_reg, bool read_backward, Label* on_no_match) {
   Label fallthrough;
   __ Ld(a0, register_location(start_reg));      // Index of start of capture.
   __ Ld(a1, register_location(start_reg + 1));  // Index of end of capture.
@@ -356,7 +355,7 @@ void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
     //   a0: Address byte_offset1 - Address captured substring's start.
     //   a1: Address byte_offset2 - Address of current character position.
     //   a2: size_t byte_length - length of capture in bytes(!).
-    //   a3: Isolate* isolate or 0 if unicode flag.
+    //   a3: Isolate* isolate.
 
     // Address of start of capture.
     __ Daddu(a0, a0, Operand(end_of_input_address()));
@@ -370,14 +369,7 @@ void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
       __ Dsubu(a1, a1, Operand(s3));
     }
     // Isolate.
-#ifdef V8_INTL_SUPPORT
-    if (unicode) {
-      __ mov(a3, zero_reg);
-    } else  // NOLINT
-#endif      // V8_INTL_SUPPORT
-    {
-      __ li(a3, Operand(ExternalReference::isolate_address(masm_->isolate())));
-    }
+    __ li(a3, Operand(ExternalReference::isolate_address(masm_->isolate())));
 
     {
       AllowExternalCallThatCantCauseGC scope(masm_);
@@ -404,7 +396,6 @@ void RegExpMacroAssemblerMIPS::CheckNotBackReferenceIgnoreCase(
   __ bind(&fallthrough);
 }
 
-
 void RegExpMacroAssemblerMIPS::CheckNotBackReference(int start_reg,
                                                      bool read_backward,
                                                      Label* on_no_match) {

src/regexp/mips64/regexp-macro-assembler-mips64.h

@@ -37,7 +37,7 @@ class V8_EXPORT_PRIVATE RegExpMacroAssemblerMIPS
   virtual void CheckNotBackReference(int start_reg, bool read_backward,
                                      Label* on_no_match);
   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
-                                               bool read_backward, bool unicode,
+                                               bool read_backward,
                                                Label* on_no_match);
   virtual void CheckNotCharacter(uint32_t c, Label* on_not_equal);
   virtual void CheckNotCharacterAfterAnd(uint32_t c,