8003195: AbstractAssembler should not store code pointers but use the CodeSection directly

Reviewed-by: twisti, kvn
Contributed-by: NBharadwaj Yadavalli <bharadwaj.yadavalli@oracle.com>

src/cpu/x86/vm/assembler_x86.cpp

@@ -1154,7 +1154,7 @@ void Assembler::call_literal(address entry, RelocationHolder const& rspec) {
   assert(entry != NULL, "call most probably wrong");
   InstructionMark im(this);
   emit_byte(0xE8);
-  intptr_t disp = entry - (_code_pos + sizeof(int32_t));
+  intptr_t disp = entry - (pc() + sizeof(int32_t));
   assert(is_simm32(disp), "must be 32bit offset (call2)");
   // Technically, should use call32_operand, but this format is
   // implied by the fact that we're emitting a call instruction.
@@ -1417,7 +1417,7 @@ void Assembler::jcc(Condition cc, Label& L, bool maybe_short) {
 
     const int short_size = 2;
     const int long_size = 6;
-    intptr_t offs = (intptr_t)dst - (intptr_t)_code_pos;
+    intptr_t offs = (intptr_t)dst - (intptr_t)pc();
     if (maybe_short && is8bit(offs - short_size)) {
       // 0111 tttn #8-bit disp
       emit_byte(0x70 | cc);
@@ -1447,14 +1447,14 @@ void Assembler::jccb(Condition cc, Label& L) {
     const int short_size = 2;
     address entry = target(L);
 #ifdef ASSERT
-    intptr_t dist = (intptr_t)entry - ((intptr_t)_code_pos + short_size);
+    intptr_t dist = (intptr_t)entry - ((intptr_t)pc() + short_size);
     intptr_t delta = short_branch_delta();
     if (delta != 0) {
       dist += (dist < 0 ? (-delta) :delta);
     }
     assert(is8bit(dist), "Dispacement too large for a short jmp");
 #endif
-    intptr_t offs = (intptr_t)entry - (intptr_t)_code_pos;
+    intptr_t offs = (intptr_t)entry - (intptr_t)pc();
     // 0111 tttn #8-bit disp
     emit_byte(0x70 | cc);
     emit_byte((offs - short_size) & 0xFF);
@@ -1480,7 +1480,7 @@ void Assembler::jmp(Label& L, bool maybe_short) {
     InstructionMark im(this);
     const int short_size = 2;
     const int long_size = 5;
-    intptr_t offs = entry - _code_pos;
+    intptr_t offs = entry - pc();
     if (maybe_short && is8bit(offs - short_size)) {
       emit_byte(0xEB);
       emit_byte((offs - short_size) & 0xFF);
@@ -1510,7 +1510,7 @@ void Assembler::jmp_literal(address dest, RelocationHolder const& rspec) {
   InstructionMark im(this);
   emit_byte(0xE9);
   assert(dest != NULL, "must have a target");
-  intptr_t disp = dest - (_code_pos + sizeof(int32_t));
+  intptr_t disp = dest - (pc() + sizeof(int32_t));
   assert(is_simm32(disp), "must be 32bit offset (jmp)");
   emit_data(disp, rspec.reloc(), call32_operand);
 }
@@ -1521,14 +1521,14 @@ void Assembler::jmpb(Label& L) {
     address entry = target(L);
     assert(entry != NULL, "jmp most probably wrong");
 #ifdef ASSERT
-    intptr_t dist = (intptr_t)entry - ((intptr_t)_code_pos + short_size);
+    intptr_t dist = (intptr_t)entry - ((intptr_t)pc() + short_size);
     intptr_t delta = short_branch_delta();
     if (delta != 0) {
       dist += (dist < 0 ? (-delta) :delta);
     }
     assert(is8bit(dist), "Dispacement too large for a short jmp");
 #endif
-    intptr_t offs = entry - _code_pos;
+    intptr_t offs = entry - pc();
     emit_byte(0xEB);
     emit_byte((offs - short_size) & 0xFF);
   } else {
@@ -4361,7 +4361,7 @@ bool Assembler::reachable(AddressLiteral adr) {
   disp = (int64_t)adr._target - ((int64_t)CodeCache::high_bound() + sizeof(int));
   if (!is_simm32(disp)) return false;
 
-  disp = (int64_t)adr._target - ((int64_t)_code_pos + sizeof(int));
+  disp = (int64_t)adr._target - ((int64_t)pc() + sizeof(int));
 
   // Because rip relative is a disp + address_of_next_instruction and we
   // don't know the value of address_of_next_instruction we apply a fudge factor
@@ -4392,7 +4392,7 @@ void Assembler::emit_data64(jlong data,
                             relocInfo::relocType rtype,
                             int format) {
   if (rtype == relocInfo::none) {
-    emit_long64(data);
+    emit_int64(data);
   } else {
     emit_data64(data, Relocation::spec_simple(rtype), format);
   }
@@ -4410,7 +4410,7 @@ void Assembler::emit_data64(jlong data,
 #ifdef ASSERT
   check_relocation(rspec, format);
 #endif
-  emit_long64(data);
+  emit_int64(data);
 }
 
 int Assembler::prefix_and_encode(int reg_enc, bool byteinst) {
@@ -4943,7 +4943,7 @@ void Assembler::mov64(Register dst, int64_t imm64) {
   InstructionMark im(this);
   int encode = prefixq_and_encode(dst->encoding());
   emit_byte(0xB8 | encode);
-  emit_long64(imm64);
+  emit_int64(imm64);
 }
 
 void Assembler::mov_literal64(Register dst, intptr_t imm64, RelocationHolder const& rspec) {
@@ -7891,7 +7891,7 @@ void MacroAssembler::jump_cc(Condition cc, AddressLiteral dst) {
     relocate(dst.reloc());
     const int short_size = 2;
     const int long_size = 6;
-    int offs = (intptr_t)dst.target() - ((intptr_t)_code_pos);
+    int offs = (intptr_t)dst.target() - ((intptr_t)pc());
     if (dst.reloc() == relocInfo::none && is8bit(offs - short_size)) {
       // 0111 tttn #8-bit disp
       emit_byte(0x70 | cc);

src/cpu/x86/vm/assembler_x86.hpp

@@ -706,8 +706,6 @@ private:
   void check_relocation(RelocationHolder const& rspec, int format);
   #endif
 
-  inline void emit_long64(jlong x);
-
   void emit_data(jint data, relocInfo::relocType    rtype, int format);
   void emit_data(jint data, RelocationHolder const& rspec, int format);
   void emit_data64(jlong data, relocInfo::relocType rtype, int format = 0);

src/cpu/x86/vm/assembler_x86.inline.hpp

@@ -87,12 +87,6 @@ inline void Assembler::prefixq(Address adr, Register reg) {}
 
 inline void Assembler::prefix(Address adr, XMMRegister reg) {}
 inline void Assembler::prefixq(Address adr, XMMRegister reg) {}
-#else
-inline void Assembler::emit_long64(jlong x) {
-  *(jlong*) _code_pos = x;
-  _code_pos += sizeof(jlong);
-  code_section()->set_end(_code_pos);
-}
 #endif // _LP64
 
 #endif // CPU_X86_VM_ASSEMBLER_X86_INLINE_HPP

src/share/vm/asm/assembler.cpp

@@ -56,16 +56,13 @@ AbstractAssembler::AbstractAssembler(CodeBuffer* code) {
   if (code == NULL)  return;
   CodeSection* cs = code->insts();
   cs->clear_mark();   // new assembler kills old mark
-  _code_section = cs;
-  _code_begin  = cs->start();
-  _code_limit  = cs->limit();
-  _code_pos    = cs->end();
-  _oop_recorder= code->oop_recorder();
-  DEBUG_ONLY( _short_branch_delta = 0; )
-  if (_code_begin == NULL)  {
+  if (cs->start() == NULL)  {
     vm_exit_out_of_memory(0, err_msg("CodeCache: no room for %s",
                                      code->name()));
   }
+  _code_section = cs;
+  _oop_recorder= code->oop_recorder();
+  DEBUG_ONLY( _short_branch_delta = 0; )
 }
 
 void AbstractAssembler::set_code_section(CodeSection* cs) {
@@ -73,9 +70,6 @@ void AbstractAssembler::set_code_section(CodeSection* cs) {
   assert(cs->is_allocated(), "need to pre-allocate this section");
   cs->clear_mark();  // new assembly into this section kills old mark
   _code_section = cs;
-  _code_begin  = cs->start();
-  _code_limit  = cs->limit();
-  _code_pos    = cs->end();
 }
 
 // Inform CodeBuffer that incoming code and relocation will be for stubs
@@ -83,7 +77,6 @@ address AbstractAssembler::start_a_stub(int required_space) {
   CodeBuffer*  cb = code();
   CodeSection* cs = cb->stubs();
   assert(_code_section == cb->insts(), "not in insts?");
-  sync();
   if (cs->maybe_expand_to_ensure_remaining(required_space)
       && cb->blob() == NULL) {
     return NULL;
@@ -96,7 +89,6 @@ address AbstractAssembler::start_a_stub(int required_space) {
 // Should not be called if start_a_stub() returned NULL
 void AbstractAssembler::end_a_stub() {
   assert(_code_section == code()->stubs(), "not in stubs?");
-  sync();
   set_code_section(code()->insts());
 }
 
@@ -105,7 +97,6 @@ address AbstractAssembler::start_a_const(int required_space, int required_align)
   CodeBuffer*  cb = code();
   CodeSection* cs = cb->consts();
   assert(_code_section == cb->insts() || _code_section == cb->stubs(), "not in insts/stubs?");
-  sync();
   address end = cs->end();
   int pad = -(intptr_t)end & (required_align-1);
   if (cs->maybe_expand_to_ensure_remaining(pad + required_space)) {
@@ -124,12 +115,10 @@ address AbstractAssembler::start_a_const(int required_space, int required_align)
 // in section cs (insts or stubs).
 void AbstractAssembler::end_a_const(CodeSection* cs) {
   assert(_code_section == code()->consts(), "not in consts?");
-  sync();
   set_code_section(cs);
 }
 
 void AbstractAssembler::flush() {
-  sync();
   ICache::invalidate_range(addr_at(0), offset());
 }
 

src/share/vm/asm/assembler.hpp

@@ -201,13 +201,10 @@ class AbstractAssembler : public ResourceObj  {
 
  protected:
   CodeSection* _code_section;          // section within the code buffer
-  address      _code_begin;            // first byte of code buffer
-  address      _code_limit;            // first byte after code buffer
-  address      _code_pos;              // current code generation position
   OopRecorder* _oop_recorder;          // support for relocInfo::oop_type
 
   // Code emission & accessing
-  address addr_at(int pos) const       { return _code_begin + pos; }
+  inline address addr_at(int pos) const;
 
   // This routine is called with a label is used for an address.
   // Labels and displacements truck in offsets, but target must return a PC.
@@ -217,10 +214,18 @@ class AbstractAssembler : public ResourceObj  {
   bool isByte(int x) const             { return 0 <= x && x < 0x100; }
   bool isShiftCount(int x) const       { return 0 <= x && x < 32; }
 
-  void emit_byte(int x);  // emit a single byte
-  void emit_word(int x);  // emit a 16-bit word (not a wordSize word!)
-  void emit_long(jint x); // emit a 32-bit word (not a longSize word!)
-  void emit_address(address x); // emit an address (not a longSize word!)
+  void emit_byte(int x)  { emit_int8 (x); }  // deprecated
+  void emit_word(int x)  { emit_int16(x); }  // deprecated
+  void emit_long(jint x) { emit_int32(x); }  // deprecated
+
+  inline void emit_int8(  int8_t  x);
+  inline void emit_int16( int16_t x);
+  inline void emit_int32( int32_t x);
+  inline void emit_int64( int64_t x);
+
+  inline void emit_float( jfloat  x);
+  inline void emit_double(jdouble x);
+  inline void emit_address(address x);
 
   // Instruction boundaries (required when emitting relocatable values).
   class InstructionMark: public StackObj {
@@ -278,9 +283,6 @@ class AbstractAssembler : public ResourceObj  {
   // Creation
   AbstractAssembler(CodeBuffer* code);
 
-  // save end pointer back to code buf.
-  void sync();
-
   // ensure buf contains all code (call this before using/copying the code)
   void flush();
 
@@ -308,12 +310,13 @@ class AbstractAssembler : public ResourceObj  {
   static bool is_simm32(intptr_t x) { return is_simm(x, 32); }
 
   // Accessors
-  CodeBuffer*   code() const;          // _code_section->outer()
   CodeSection*  code_section() const   { return _code_section; }
-  int           sect() const;          // return _code_section->index()
-  address       pc() const             { return _code_pos; }
-  int           offset() const         { return _code_pos - _code_begin; }
-  int           locator() const;       // CodeBuffer::locator(offset(), sect())
+  inline CodeBuffer*   code() const;
+  inline int           sect() const;
+  inline address       pc() const;
+  inline int           offset() const;
+  inline int           locator() const;       // CodeBuffer::locator(offset(), sect())
+
   OopRecorder*  oop_recorder() const   { return _oop_recorder; }
   void      set_oop_recorder(OopRecorder* r) { _oop_recorder = r; }
 
@@ -358,8 +361,7 @@ class AbstractAssembler : public ResourceObj  {
     CodeSection* c1 = _code_section;
     address ptr = start_a_const(sizeof(c), sizeof(c));
     if (ptr != NULL) {
-      *(jlong*)ptr = c;
-      _code_pos = ptr + sizeof(c);
+      emit_int64(c);
       end_a_const(c1);
     }
     return ptr;
@@ -368,8 +370,7 @@ class AbstractAssembler : public ResourceObj  {
     CodeSection* c1 = _code_section;
     address ptr = start_a_const(sizeof(c), sizeof(c));
     if (ptr != NULL) {
-      *(jdouble*)ptr = c;
-      _code_pos = ptr + sizeof(c);
+      emit_double(c);
       end_a_const(c1);
     }
     return ptr;
@@ -378,8 +379,7 @@ class AbstractAssembler : public ResourceObj  {
     CodeSection* c1 = _code_section;
     address ptr = start_a_const(sizeof(c), sizeof(c));
     if (ptr != NULL) {
-      *(jfloat*)ptr = c;
-      _code_pos = ptr + sizeof(c);
+      emit_float(c);
       end_a_const(c1);
     }
     return ptr;
@@ -388,8 +388,7 @@ class AbstractAssembler : public ResourceObj  {
     CodeSection* c1 = _code_section;
     address ptr = start_a_const(sizeof(c), sizeof(c));
     if (ptr != NULL) {
-      *(address*)ptr = c;
-      _code_pos = ptr + sizeof(c);
+      emit_address(c);
       end_a_const(c1);
     }
     return ptr;
@@ -399,8 +398,7 @@ class AbstractAssembler : public ResourceObj  {
     address ptr = start_a_const(sizeof(c), sizeof(c));
     if (ptr != NULL) {
       relocate(rspec);
-      *(address*)ptr = c;
-      _code_pos = ptr + sizeof(c);
+      emit_address(c);
       end_a_const(c1);
     }
     return ptr;

src/share/vm/asm/assembler.inline.hpp

@@ -30,49 +30,27 @@
 #include "compiler/disassembler.hpp"
 #include "runtime/threadLocalStorage.hpp"
 
-inline void AbstractAssembler::sync() {
-  CodeSection* cs = code_section();
-  guarantee(cs->start() == _code_begin, "must not shift code buffer");
-  cs->set_end(_code_pos);
+inline address AbstractAssembler::addr_at(int pos) const {
+  return code_section()->start() + pos;
 }
 
-inline void AbstractAssembler::emit_byte(int x) {
-  assert(isByte(x), "not a byte");
-  *(unsigned char*)_code_pos = (unsigned char)x;
-  _code_pos += sizeof(unsigned char);
-  sync();
-}
-
-
-inline void AbstractAssembler::emit_word(int x) {
-  *(short*)_code_pos = (short)x;
-  _code_pos += sizeof(short);
-  sync();
-}
-
-
-inline void AbstractAssembler::emit_long(jint x) {
-  *(jint*)_code_pos = x;
-  _code_pos += sizeof(jint);
-  sync();
-}
+void AbstractAssembler::emit_int8(int8_t x)     { code_section()->emit_int8 (x); }
+void AbstractAssembler::emit_int16(int16_t x)   { code_section()->emit_int16(x); }
+void AbstractAssembler::emit_int32(int32_t x)   { code_section()->emit_int32(x); }
+void AbstractAssembler::emit_int64(int64_t x)   { code_section()->emit_int64(x); }
 
-inline void AbstractAssembler::emit_address(address x) {
-  *(address*)_code_pos = x;
-  _code_pos += sizeof(address);
-  sync();
-}
+void AbstractAssembler::emit_float(jfloat  x)   { code_section()->emit_float(x); }
+void AbstractAssembler::emit_double(jdouble x)  { code_section()->emit_double(x); }
+void AbstractAssembler::emit_address(address x) { code_section()->emit_address(x); }
 
 inline address AbstractAssembler::inst_mark() const {
   return code_section()->mark();
 }
 
-
 inline void AbstractAssembler::set_inst_mark() {
   code_section()->set_mark();
 }
 
-
 inline void AbstractAssembler::clear_inst_mark() {
   code_section()->clear_mark();
 }
@@ -80,9 +58,9 @@ inline void AbstractAssembler::clear_inst_mark() {
 
 inline void AbstractAssembler::relocate(RelocationHolder const& rspec, int format) {
   assert(!pd_check_instruction_mark()
-         || inst_mark() == NULL || inst_mark() == _code_pos,
+         || inst_mark() == NULL || inst_mark() == code_section()->end(),
          "call relocate() between instructions");
-  code_section()->relocate(_code_pos, rspec, format);
+  code_section()->relocate(code_section()->end(), rspec, format);
 }
 
 
@@ -94,6 +72,14 @@ inline int AbstractAssembler::sect() const {
   return code_section()->index();
 }
 
+inline address AbstractAssembler::pc() const {
+  return code_section()->end();
+}
+
+inline int AbstractAssembler::offset() const {
+  return code_section()->size();
+}
+
 inline int AbstractAssembler::locator() const {
   return CodeBuffer::locator(offset(), sect());
 }

src/share/vm/asm/codeBuffer.hpp

@@ -30,8 +30,6 @@
 #include "code/relocInfo.hpp"
 
 class  CodeComments;
-class  AbstractAssembler;
-class  MacroAssembler;
 class  PhaseCFG;
 class  Compile;
 class  BufferBlob;
@@ -194,10 +192,14 @@ class CodeSection VALUE_OBJ_CLASS_SPEC {
   }
 
   // Code emission
-  void emit_int8 (int8_t  x) { *((int8_t*)  end()) = x; set_end(end() + 1); }
-  void emit_int16(int16_t x) { *((int16_t*) end()) = x; set_end(end() + 2); }
-  void emit_int32(int32_t x) { *((int32_t*) end()) = x; set_end(end() + 4); }
-  void emit_int64(int64_t x) { *((int64_t*) end()) = x; set_end(end() + 8); }
+  void emit_int8 ( int8_t  x)  { *((int8_t*)  end()) = x; set_end(end() + sizeof(int8_t)); }
+  void emit_int16( int16_t x)  { *((int16_t*) end()) = x; set_end(end() + sizeof(int16_t)); }
+  void emit_int32( int32_t x)  { *((int32_t*) end()) = x; set_end(end() + sizeof(int32_t)); }
+  void emit_int64( int64_t x)  { *((int64_t*) end()) = x; set_end(end() + sizeof(int64_t)); }
+
+  void emit_float( jfloat  x)  { *((jfloat*)  end()) = x; set_end(end() + sizeof(jfloat)); }
+  void emit_double(jdouble x)  { *((jdouble*) end()) = x; set_end(end() + sizeof(jdouble)); }
+  void emit_address(address x) { *((address*) end()) = x; set_end(end() + sizeof(address)); }
 
   // Share a scratch buffer for relocinfo.  (Hacky; saves a resource allocation.)
   void initialize_shared_locs(relocInfo* buf, int length);