PPC/s390: [compiler] Remove delayed string constants

Port de04959f

Original Commit Message:

    StringConstantXXX were introduced when we switched to concurrent
    compilation, as a way to build strings in Turbofan in a background
    thread, without having to actually allocate them on the main heap
    from the background. See https://crrev.com/c/1221807.

    Now that we have local heaps, we can actually allocate strings from
    the background, making StringConstantXXX useless.

    Moreover, we would fold constant string concatenations into
    ConsString, which sounds a bit dubious for performance. Now, small
    constant string concatenations will be folded into SeqStrings, while
    larger ones will remain ConsString, just to avoid the quadratic
    worst-case.

R=dmercadier@chromium.org, joransiu@ca.ibm.com, junyan@redhat.com, midawson@redhat.com
BUG=
LOG=N

Change-Id: I0fb010dfda4a94ba8c5d09de96fa1932c6c91113
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3826049Reviewed-by: Darius Mercadier <dmercadier@chromium.org>
Commit-Queue: Milad Farazmand <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#82416}

src/codegen/ppc/assembler-ppc.cc

@@ -46,7 +46,6 @@
 #include "src/base/cpu.h"
 #include "src/codegen/macro-assembler.h"
 #include "src/codegen/ppc/assembler-ppc-inl.h"
-#include "src/codegen/string-constants.h"
 #include "src/deoptimizer/deoptimizer.h"
 
 namespace v8 {
@@ -194,15 +193,8 @@ Operand Operand::EmbeddedNumber(double value) {
   int32_t smi;
   if (DoubleToSmiInteger(value, &smi)) return Operand(Smi::FromInt(smi));
   Operand result(0, RelocInfo::FULL_EMBEDDED_OBJECT);
-  result.is_heap_object_request_ = true;
-  result.value_.heap_object_request = HeapObjectRequest(value);
-  return result;
-}
-
-Operand Operand::EmbeddedStringConstant(const StringConstantBase* str) {
-  Operand result(0, RelocInfo::FULL_EMBEDDED_OBJECT);
-  result.is_heap_object_request_ = true;
-  result.value_.heap_object_request = HeapObjectRequest(str);
+  result.is_heap_number_request_ = true;
+  result.value_.heap_number_request = HeapNumberRequest(value);
   return result;
 }
 
@@ -215,23 +207,12 @@ MemOperand::MemOperand(Register ra, Register rb)
 MemOperand::MemOperand(Register ra, Register rb, int64_t offset)
     : ra_(ra), offset_(offset), rb_(rb) {}
 
-void Assembler::AllocateAndInstallRequestedHeapObjects(Isolate* isolate) {
-  DCHECK_IMPLIES(isolate == nullptr, heap_object_requests_.empty());
-  for (auto& request : heap_object_requests_) {
-    Handle<HeapObject> object;
-    switch (request.kind()) {
-      case HeapObjectRequest::kHeapNumber: {
-        object = isolate->factory()->NewHeapNumber<AllocationType::kOld>(
+void Assembler::AllocateAndInstallRequestedHeapNumbers(Isolate* isolate) {
+  DCHECK_IMPLIES(isolate == nullptr, heap_number_requests_.empty());
+  for (auto& request : heap_number_requests_) {
+    Handle<HeapObject> object =
+        isolate->factory()->NewHeapNumber<AllocationType::kOld>(
             request.heap_number());
-        break;
-      }
-      case HeapObjectRequest::kStringConstant: {
-        const StringConstantBase* str = request.string();
-        CHECK_NOT_NULL(str);
-        object = str->AllocateStringConstant(isolate);
-        break;
-      }
-    }
     Address pc = reinterpret_cast<Address>(buffer_start_) + request.offset();
     Address constant_pool = kNullAddress;
     set_target_address_at(pc, constant_pool, object.address(),
@@ -280,7 +261,7 @@ void Assembler::GetCode(Isolate* isolate, CodeDesc* desc,
 
   int code_comments_size = WriteCodeComments();
 
-  AllocateAndInstallRequestedHeapObjects(isolate);
+  AllocateAndInstallRequestedHeapNumbers(isolate);
 
   // Set up code descriptor.
   // TODO(jgruber): Reconsider how these offsets and sizes are maintained up to
@@ -1378,8 +1359,8 @@ bool Operand::must_output_reloc_info(const Assembler* assembler) const {
 // and only use the generic version when we require a fixed sequence
 void Assembler::mov(Register dst, const Operand& src) {
   intptr_t value;
-  if (src.IsHeapObjectRequest()) {
-    RequestHeapObject(src.heap_object_request());
+  if (src.IsHeapNumberRequest()) {
+    RequestHeapNumber(src.heap_number_request());
     value = 0;
   } else {
     value = src.immediate();
@@ -1393,7 +1374,7 @@ void Assembler::mov(Register dst, const Operand& src) {
          (!is_int16(value) ||
           !(CpuFeatures::IsSupported(PPC_10_PLUS) && is_int34(value)))));
 
-  if (!src.IsHeapObjectRequest() &&
+  if (!src.IsHeapNumberRequest() &&
       use_constant_pool_for_mov(dst, src, canOptimize)) {
     DCHECK(is_constant_pool_available());
     if (relocatable) {

src/codegen/ppc/assembler-ppc.h

@@ -83,7 +83,6 @@ class V8_EXPORT_PRIVATE Operand {
   V8_INLINE explicit Operand(Register rm);
 
   static Operand EmbeddedNumber(double number);  // Smi or HeapNumber.
-  static Operand EmbeddedStringConstant(const StringConstantBase* str);
 
   // Return true if this is a register operand.
   V8_INLINE bool is_reg() const { return rm_.is_valid(); }
@@ -92,34 +91,34 @@ class V8_EXPORT_PRIVATE Operand {
 
   inline intptr_t immediate() const {
     DCHECK(IsImmediate());
-    DCHECK(!IsHeapObjectRequest());
+    DCHECK(!IsHeapNumberRequest());
     return value_.immediate;
   }
   bool IsImmediate() const { return !rm_.is_valid(); }
 
-  HeapObjectRequest heap_object_request() const {
-    DCHECK(IsHeapObjectRequest());
-    return value_.heap_object_request;
+  HeapNumberRequest heap_number_request() const {
+    DCHECK(IsHeapNumberRequest());
+    return value_.heap_number_request;
   }
 
   Register rm() const { return rm_; }
 
-  bool IsHeapObjectRequest() const {
-    DCHECK_IMPLIES(is_heap_object_request_, IsImmediate());
-    DCHECK_IMPLIES(is_heap_object_request_,
+  bool IsHeapNumberRequest() const {
+    DCHECK_IMPLIES(is_heap_number_request_, IsImmediate());
+    DCHECK_IMPLIES(is_heap_number_request_,
                    rmode_ == RelocInfo::FULL_EMBEDDED_OBJECT ||
                        rmode_ == RelocInfo::CODE_TARGET);
-    return is_heap_object_request_;
+    return is_heap_number_request_;
   }
 
  private:
   Register rm_ = no_reg;
   union Value {
     Value() {}
-    HeapObjectRequest heap_object_request;  // if is_heap_object_request_
+    HeapNumberRequest heap_number_request;  // if is_heap_number_request_
     intptr_t immediate;                     // otherwise
   } value_;                                 // valid if rm_ == no_reg
-  bool is_heap_object_request_ = false;
+  bool is_heap_number_request_ = false;
 
   RelocInfo::Mode rmode_;
 
@@ -1533,7 +1532,7 @@ class Assembler : public AssemblerBase {
   Trampoline trampoline_;
   bool internal_trampoline_exception_;
 
-  void AllocateAndInstallRequestedHeapObjects(Isolate* isolate);
+  void AllocateAndInstallRequestedHeapNumbers(Isolate* isolate);
 
   int WriteCodeComments();
 

src/codegen/s390/assembler-s390.cc

@@ -49,7 +49,6 @@
 #include "src/base/cpu.h"
 #include "src/codegen/macro-assembler.h"
 #include "src/codegen/s390/assembler-s390-inl.h"
-#include "src/codegen/string-constants.h"
 #include "src/deoptimizer/deoptimizer.h"
 
 namespace v8 {
@@ -328,15 +327,8 @@ Operand Operand::EmbeddedNumber(double value) {
   int32_t smi;
   if (DoubleToSmiInteger(value, &smi)) return Operand(Smi::FromInt(smi));
   Operand result(0, RelocInfo::FULL_EMBEDDED_OBJECT);
-  result.is_heap_object_request_ = true;
-  result.value_.heap_object_request = HeapObjectRequest(value);
-  return result;
-}
-
-Operand Operand::EmbeddedStringConstant(const StringConstantBase* str) {
-  Operand result(0, RelocInfo::FULL_EMBEDDED_OBJECT);
-  result.is_heap_object_request_ = true;
-  result.value_.heap_object_request = HeapObjectRequest(str);
+  result.is_heap_number_request_ = true;
+  result.value_.heap_number_request = HeapNumberRequest(value);
   return result;
 }
 
@@ -346,27 +338,15 @@ MemOperand::MemOperand(Register rn, int32_t offset)
 MemOperand::MemOperand(Register rx, Register rb, int32_t offset)
     : baseRegister(rb), indexRegister(rx), offset_(offset) {}
 
-void Assembler::AllocateAndInstallRequestedHeapObjects(Isolate* isolate) {
-  DCHECK_IMPLIES(isolate == nullptr, heap_object_requests_.empty());
-  for (auto& request : heap_object_requests_) {
-    Handle<HeapObject> object;
+void Assembler::AllocateAndInstallRequestedHeapNumbers(Isolate* isolate) {
+  DCHECK_IMPLIES(isolate == nullptr, heap_number_requests_.empty());
+  for (auto& request : heap_number_requests_) {
     Address pc = reinterpret_cast<Address>(buffer_start_) + request.offset();
-    switch (request.kind()) {
-      case HeapObjectRequest::kHeapNumber: {
-        object = isolate->factory()->NewHeapNumber<AllocationType::kOld>(
+    Handle<HeapObject> object =
+        isolate->factory()->NewHeapNumber<AllocationType::kOld>(
             request.heap_number());
-        set_target_address_at(pc, kNullAddress, object.address(),
-                              SKIP_ICACHE_FLUSH);
-        break;
-      }
-      case HeapObjectRequest::kStringConstant: {
-        const StringConstantBase* str = request.string();
-        CHECK_NOT_NULL(str);
-        set_target_address_at(pc, kNullAddress,
-                              str->AllocateStringConstant(isolate).address());
-        break;
-      }
-    }
+    set_target_address_at(pc, kNullAddress, object.address(),
+                          SKIP_ICACHE_FLUSH);
   }
 }
 
@@ -397,7 +377,7 @@ void Assembler::GetCode(Isolate* isolate, CodeDesc* desc,
 
   int code_comments_size = WriteCodeComments();
 
-  AllocateAndInstallRequestedHeapObjects(isolate);
+  AllocateAndInstallRequestedHeapNumbers(isolate);
 
   // Set up code descriptor.
   // TODO(jgruber): Reconsider how these offsets and sizes are maintained up to

src/codegen/s390/assembler-s390.h

@@ -111,7 +111,6 @@ class V8_EXPORT_PRIVATE Operand {
   V8_INLINE explicit Operand(Register rm);
 
   static Operand EmbeddedNumber(double value);  // Smi or HeapNumber
-  static Operand EmbeddedStringConstant(const StringConstantBase* str);
 
   // Return true if this is a register operand.
   V8_INLINE bool is_reg() const { return rm_.is_valid(); }
@@ -120,13 +119,13 @@ class V8_EXPORT_PRIVATE Operand {
 
   inline intptr_t immediate() const {
     DCHECK(!rm_.is_valid());
-    DCHECK(!is_heap_object_request());
+    DCHECK(!is_heap_number_request());
     return value_.immediate;
   }
 
-  HeapObjectRequest heap_object_request() const {
-    DCHECK(is_heap_object_request());
-    return value_.heap_object_request;
+  HeapNumberRequest heap_number_request() const {
+    DCHECK(is_heap_number_request());
+    return value_.heap_number_request;
   }
 
   inline void setBits(int n) {
@@ -136,12 +135,12 @@ class V8_EXPORT_PRIVATE Operand {
 
   Register rm() const { return rm_; }
 
-  bool is_heap_object_request() const {
-    DCHECK_IMPLIES(is_heap_object_request_, !rm_.is_valid());
-    DCHECK_IMPLIES(is_heap_object_request_,
+  bool is_heap_number_request() const {
+    DCHECK_IMPLIES(is_heap_number_request_, !rm_.is_valid());
+    DCHECK_IMPLIES(is_heap_number_request_,
                    rmode_ == RelocInfo::FULL_EMBEDDED_OBJECT ||
                        rmode_ == RelocInfo::CODE_TARGET);
-    return is_heap_object_request_;
+    return is_heap_number_request_;
   }
 
   RelocInfo::Mode rmode() const { return rmode_; }
@@ -150,10 +149,10 @@ class V8_EXPORT_PRIVATE Operand {
   Register rm_ = no_reg;
   union Value {
     Value() {}
-    HeapObjectRequest heap_object_request;  // if is_heap_object_request_
+    HeapNumberRequest heap_number_request;  // if is_heap_number_request_
     intptr_t immediate;                     // otherwise
   } value_;                                 // valid if rm_ == no_reg
-  bool is_heap_object_request_ = false;
+  bool is_heap_number_request_ = false;
 
   RelocInfo::Mode rmode_;
 
@@ -1467,7 +1466,7 @@ class V8_EXPORT_PRIVATE Assembler : public AssemblerBase {
   void bind_to(Label* L, int pos);
   void next(Label* L);
 
-  void AllocateAndInstallRequestedHeapObjects(Isolate* isolate);
+  void AllocateAndInstallRequestedHeapNumbers(Isolate* isolate);
 
   int WriteCodeComments();
 

src/codegen/s390/macro-assembler-s390.cc

@@ -2628,8 +2628,8 @@ void TurboAssembler::mov(Register dst, Register src) { lgr(dst, src); }
 void TurboAssembler::mov(Register dst, const Operand& src) {
   int64_t value = 0;
 
-  if (src.is_heap_object_request()) {
-    RequestHeapObject(src.heap_object_request());
+  if (src.is_heap_number_request()) {
+    RequestHeapNumber(src.heap_number_request());
   } else {
     value = src.immediate();
   }

src/compiler/backend/ppc/code-generator-ppc.cc

@@ -77,9 +77,6 @@ class PPCOperandConverter final : public InstructionOperandConverter {
 #endif
       case Constant::kExternalReference:
         return Operand(constant.ToExternalReference());
-      case Constant::kDelayedStringConstant:
-        return Operand::EmbeddedStringConstant(
-            constant.ToDelayedStringConstant());
       case Constant::kCompressedHeapObject:
       case Constant::kHeapObject:
       case Constant::kRpoNumber:
@@ -4343,10 +4340,6 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         case Constant::kExternalReference:
           __ Move(dst, src.ToExternalReference());
           break;
-        case Constant::kDelayedStringConstant:
-          __ mov(dst, Operand::EmbeddedStringConstant(
-                          src.ToDelayedStringConstant()));
-          break;
         case Constant::kHeapObject: {
           Handle<HeapObject> src_object = src.ToHeapObject();
           RootIndex index;

src/compiler/backend/s390/code-generator-s390.cc

@@ -72,9 +72,6 @@ class S390OperandConverter final : public InstructionOperandConverter {
 #endif
       case Constant::kExternalReference:
         return Operand(constant.ToExternalReference());
-      case Constant::kDelayedStringConstant:
-        return Operand::EmbeddedStringConstant(
-            constant.ToDelayedStringConstant());
       case Constant::kCompressedHeapObject:
       case Constant::kHeapObject:
       case Constant::kRpoNumber:
@@ -3703,10 +3700,6 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         case Constant::kExternalReference:
           __ Move(dst, src.ToExternalReference());
           break;
-        case Constant::kDelayedStringConstant:
-          __ mov(dst, Operand::EmbeddedStringConstant(
-                          src.ToDelayedStringConstant()));
-          break;
         case Constant::kHeapObject: {
           Handle<HeapObject> src_object = src.ToHeapObject();
           RootIndex index;