[maglev] Use B instead of b on arm64

`MacroAssembler::B` registers its labels with the veneer pool, while
`Assembler::b` doesn't. This meant that our JumpIf (used in particular
for deopts) could run out of jump distance.

As a drive by, also limit the maximum number of deopts according to the
limit set by the deoptimizer. This turned out to not be the issue, but
we should also do it.

Bug: v8:7700
Change-Id: Ic5a8dd3b69c995375d7caab008f31ae91d9c732d
Fixed: chromium:1410080
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4224931
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85686}

src/maglev/arm64/maglev-assembler-arm64-inl.h

@@ -581,7 +581,7 @@ inline void MaglevAssembler::Jump(Label* target, Label::Distance) { B(target); }
 
 inline void MaglevAssembler::JumpIf(Condition cond, Label* target,
                                     Label::Distance) {
-  b(target, cond);
+  B(target, cond);
 }
 
 inline void MaglevAssembler::JumpIfRoot(Register with, RootIndex index,

src/maglev/arm64/maglev-assembler-arm64.cc

@@ -423,7 +423,7 @@ void MaglevAssembler::Prologue(Graph* graph) {
         Push(xzr, xzr);
       }
       Subs(count, count, Immediate(1));
-      b(&loop, gt);
+      B(&loop, gt);
     }
   }
   if (remaining_stack_slots > 0) {

src/maglev/maglev-code-generator.cc

@@ -17,6 +17,7 @@
 #include "src/common/globals.h"
 #include "src/compiler/backend/instruction.h"
 #include "src/deoptimizer/deoptimize-reason.h"
+#include "src/deoptimizer/deoptimizer.h"
 #include "src/deoptimizer/translation-array.h"
 #include "src/execution/frame-constants.h"
 #include "src/interpreter/bytecode-register.h"
@@ -1240,6 +1241,7 @@ void MaglevCodeGenerator::EmitCode() {
   processor.ProcessGraph(graph_);
   EmitDeferredCode();
   EmitDeopts();
+  if (code_gen_failed_) return;
   EmitExceptionHandlerTrampolines();
   __ FinishCode();
 }
@@ -1258,6 +1260,13 @@ void MaglevCodeGenerator::EmitDeferredCode() {
 }
 
 void MaglevCodeGenerator::EmitDeopts() {
+  const size_t num_deopts = code_gen_state_.eager_deopts().size() +
+                            code_gen_state_.lazy_deopts().size();
+  if (num_deopts > Deoptimizer::kMaxNumberOfEntries) {
+    code_gen_failed_ = true;
+    return;
+  }
+
   MaglevTranslationArrayBuilder translation_builder(
       local_isolate_, &masm_, &translation_array_builder_, &deopt_literals_);
 
@@ -1351,6 +1360,8 @@ void MaglevCodeGenerator::EmitMetadata() {
 }
 
 MaybeHandle<Code> MaglevCodeGenerator::BuildCodeObject(Isolate* isolate) {
+  if (code_gen_failed_) return {};
+
   CodeDesc desc;
   masm()->GetCode(isolate, &desc, &safepoint_table_builder_,
                   handler_table_offset_);

src/maglev/maglev-code-generator.h

@@ -55,6 +55,8 @@ class MaglevCodeGenerator final {
   IdentityMap<int, base::DefaultAllocationPolicy> deopt_literals_;
   int deopt_exit_start_offset_ = -1;
   int handler_table_offset_ = 0;
+
+  bool code_gen_failed_ = false;
 };
 
 }  // namespace maglev