8326135: Enhance adlc to report unused operands

Reviewed-by: kvn, vlivanov

src/hotspot/share/adlc/archDesc.cpp

@@ -1,5 +1,5 @@
 //
-// Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+// Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
 // DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 //
 // This code is free software; you can redistribute it and/or modify it
@@ -24,6 +24,7 @@
 
 
 // archDesc.cpp - Internal format for architecture definition
+#include <unordered_set>
 #include "adlc.hpp"
 
 static FILE *errfile = stderr;
@@ -684,6 +685,98 @@ bool ArchDesc::verify() {
   return true;
 }
 
+class MarkUsageFormClosure : public FormClosure {
+private:
+  ArchDesc* _ad;
+  std::unordered_set<Form*> *_visited;
+
+public:
+  MarkUsageFormClosure(ArchDesc* ad, std::unordered_set<Form*> *visit_map) {
+    _ad = ad;
+    _visited = visit_map;
+  }
+  virtual ~MarkUsageFormClosure() = default;
+
+  virtual void do_form(Form *form) {
+    if (_visited->find(form) == _visited->end()) {
+      _visited->insert(form);
+      form->forms_do(this);
+    }
+  }
+
+  virtual void do_form_by_name(const char* name) {
+    const Form* form = _ad->globalNames()[name];
+    if (form) {
+      do_form(const_cast<Form*>(form));
+      return;
+    }
+    RegisterForm* regs = _ad->get_registers();
+    if (regs->getRegClass(name)) {
+      do_form(regs->getRegClass(name));
+      return;
+    }
+  }
+};
+
+// check unused operands
+bool ArchDesc::check_usage() {
+  std::unordered_set<Form*> visited;
+  MarkUsageFormClosure callback(this, &visited);
+  _instructions.reset();
+  // iterate all instruction to mark used form
+  InstructForm* instr;
+  for ( ; (instr = (InstructForm*)_instructions.iter()) != nullptr; ) {
+    callback.do_form(instr);
+  }
+
+  // these forms are coded in OperandForm::is_user_name_for_sReg
+  // it may happen no instruction use these operands, like stackSlotP in aarch64,
+  // but we can not desclare they are useless.
+  callback.do_form_by_name("stackSlotI");
+  callback.do_form_by_name("stackSlotP");
+  callback.do_form_by_name("stackSlotD");
+  callback.do_form_by_name("stackSlotF");
+  callback.do_form_by_name("stackSlotL");
+
+  // sReg* are initial created by adlc in ArchDesc::initBaseOpTypes()
+  // In ARM, no definition or usage in adfile, but they are reported as unused
+  callback.do_form_by_name("sRegI");
+  callback.do_form_by_name("sRegP");
+  callback.do_form_by_name("sRegD");
+  callback.do_form_by_name("sRegF");
+  callback.do_form_by_name("sRegL");
+
+  // special generic vector operands only used in Matcher::pd_specialize_generic_vector_operand
+#if defined(AARCH64)
+  callback.do_form_by_name("vecA");
+  callback.do_form_by_name("vecD");
+  callback.do_form_by_name("vecX");
+#elif defined(AMD64)
+  callback.do_form_by_name("vecS");
+  callback.do_form_by_name("vecD");
+  callback.do_form_by_name("vecX");
+  callback.do_form_by_name("vecY");
+  callback.do_form_by_name("vecZ");
+  callback.do_form_by_name("legVecS");
+  callback.do_form_by_name("legVecD");
+  callback.do_form_by_name("legVecX");
+  callback.do_form_by_name("legVecY");
+  callback.do_form_by_name("legVecZ");
+#endif
+
+  int cnt = 0;
+  _operands.reset();
+  OperandForm* operand;
+  for ( ; (operand = (OperandForm*)_operands.iter()) != nullptr; ) {
+    if(visited.find(operand) == visited.end() && !operand->ideal_only()) {
+      fprintf(stderr, "\nWarning: unused operand (%s)", operand->_ident);
+      cnt++;
+    }
+  }
+  if (cnt) fprintf(stderr, "\n-------Warning: total %d unused operands\n", cnt);
+
+  return true;
+}
 
 void ArchDesc::dump() {
   _pre_header.dump();

src/hotspot/share/adlc/archDesc.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -226,6 +226,7 @@ public:
   inline void getForm(EncodeForm **ptr)     { *ptr = _encode; }
 
   bool verify();
+  bool check_usage();
   void dump();
 
   // Helper utility that gets MatchList components from inside MatchRule

src/hotspot/share/adlc/forms.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -362,6 +362,15 @@ void FormDict::dump() {
   _form.print(dumpkey, dumpform);
 }
 
+void FormDict::forms_do(FormClosure* f) {;
+  DictI iter(&_form);
+  for( ; iter.test(); ++iter ) {
+    Form* form = (Form*) iter._value;
+    assert(form != nullptr, "sanity");
+    f->do_form(form);
+  }
+}
+
 //------------------------------SourceForm-------------------------------------
 SourceForm::SourceForm(char* code) : _code(code) { }; // Constructor
 SourceForm::~SourceForm() {
@@ -374,3 +383,11 @@ void SourceForm::dump() {                    // Debug printer
 void SourceForm::output(FILE *fp) {
   fprintf(fp,"\n//%s\n%s\n",classname(),(_code?_code:""));
 }
+
+void FormClosure::do_form(Form* form) {
+  assert(false, "should not reach here");
+}
+
+void FormClosure::do_form_by_name(const char* name) {
+  assert(false, "should not reach here");
+}

src/hotspot/share/adlc/forms.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -58,6 +58,7 @@ class Flag;
 class RewriteRule;
 class ConstructRule;
 class FormatRule;
+class FormClosure;
 class Peephole;
 class EncClass;
 class Interface;
@@ -114,6 +115,8 @@ public:
   const Form  *operator [](const char *name) const;  // Do a lookup
 
   void dump();
+  // iterate child forms recursively
+  void forms_do(FormClosure *f);
 };
 
 // ***** Master Class for ADL Parser Forms *****
@@ -163,6 +166,9 @@ public:
   // Write info to output files
   virtual void output(FILE *fp)    { fprintf(fp,"Form Output"); }
 
+  // iterate child forms recursively
+  virtual void forms_do (FormClosure* f) { return; }
+
 public:
   // ADLC types, match the last character on ideal operands and instructions
   enum DataType {
@@ -255,6 +261,16 @@ public:
 
 };
 
+class FormClosure {
+public:
+    FormClosure() = default;
+    virtual ~FormClosure() = default;
+
+    virtual void do_form(Form* form);
+    virtual void do_form_by_name(const char* name);
+};
+
+
 //------------------------------FormList---------------------------------------
 class FormList {
 private:

src/hotspot/share/adlc/formsopt.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -198,6 +198,20 @@ void RegisterForm::output(FILE *fp) {          // Write info to output files
   fprintf(fp,"-------------------- end  RegisterForm --------------------\n");
 }
 
+void RegisterForm::forms_do(FormClosure *f) {
+  const char *name = nullptr;
+  if (_current_ac) f->do_form(_current_ac);
+  for(_rdefs.reset(); (name = _rdefs.iter()) != nullptr;) {
+    f->do_form((RegDef*)_regDef[name]);
+  }
+  for (_rclasses.reset(); (name = _rclasses.iter()) != nullptr;) {
+    f->do_form((RegClass*)_regClass[name]);
+  }
+  for (_aclasses.reset(); (name = _aclasses.iter()) != nullptr;) {
+    f->do_form((AllocClass*)_allocClass[name]);
+  }
+}
+
 //------------------------------RegDef-----------------------------------------
 // Constructor
 RegDef::RegDef(char *regname, char *callconv, char *c_conv, char * idealtype, char * encode, char * concrete)
@@ -322,6 +336,13 @@ void RegClass::output(FILE *fp) {           // Write info to output files
   fprintf(fp,"--- done with entries for reg_class %s\n\n",_classid);
 }
 
+void RegClass::forms_do(FormClosure *f) {
+  const char *name = nullptr;
+  for( _regDefs.reset(); (name = _regDefs.iter()) != nullptr; ) {
+    f->do_form((RegDef*)_regDef[name]);
+  }
+}
+
 void RegClass::declare_register_masks(FILE* fp) {
   const char* prefix = "";
   const char* rc_name_to_upper = toUpper(_classid);
@@ -436,6 +457,14 @@ void AllocClass::output(FILE *fp) {       // Write info to output files
   fprintf(fp,"--- done with entries for alloc_class %s\n\n",_classid);
 }
 
+void AllocClass::forms_do(FormClosure* f) {
+  const char *name;
+  for(_regDefs.reset(); (name = _regDefs.iter()) != nullptr;) {
+    f->do_form((RegDef*)_regDef[name]);
+  }
+  return;
+}
+
 //==============================Frame Handling=================================
 //------------------------------FrameForm--------------------------------------
 FrameForm::FrameForm() {
@@ -706,6 +735,15 @@ void Peephole::output(FILE *fp) {         // Write info to output files
   if( _next ) _next->output(fp);
 }
 
+void Peephole::forms_do(FormClosure *f) {
+  if (_predicate) f->do_form(_predicate);
+  if (_match) f->do_form(_match);
+  if (_procedure) f->do_form(_procedure);
+  if (_constraint) f->do_form(_constraint);
+  if (_replace) f->do_form(_replace);
+  return;
+}
+
 //----------------------------PeepPredicate------------------------------------
 PeepPredicate::PeepPredicate(const char* rule) : _rule(rule) {
 }

src/hotspot/share/adlc/formsopt.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -123,6 +123,7 @@ public:
 
   void dump();                     // Debug printer
   void output(FILE *fp);           // Write info to output files
+  virtual void forms_do(FormClosure* f);
 };
 
 //------------------------------RegDef-----------------------------------------
@@ -199,6 +200,7 @@ public:
 
   void dump();                  // Debug printer
   void output(FILE *fp);        // Write info to output files
+  virtual void forms_do(FormClosure* f);
 
   virtual bool has_stack_version() {
     return _stack_or_reg;
@@ -305,6 +307,11 @@ public:
   char* condition_code() {
     return _condition_code;
   }
+
+  virtual void forms_do(FormClosure* f) {
+    if (_rclasses[0]) f->do_form(_rclasses[0]);
+    if (_rclasses[1]) f->do_form(_rclasses[1]);
+  }
 };
 
 //------------------------------AllocClass-------------------------------------
@@ -325,6 +332,7 @@ public:
 
   void dump();                  // Debug printer
   void output(FILE *fp);        // Write info to output files
+  virtual void forms_do(FormClosure* f);
 };
 
 
@@ -568,6 +576,7 @@ public:
 
   void dump();                     // Debug printer
   void output(FILE *fp);           // Write info to output files
+  virtual void forms_do(FormClosure* f);
 };
 
 class PeepPredicate : public Form {

src/hotspot/share/adlc/formssel.cpp

@@ -1498,6 +1498,24 @@ void InstructForm::output(FILE *fp) {
   if (_peephole)  _peephole->output(fp);
 }
 
+void InstructForm::forms_do(FormClosure *f) {
+  if (_cisc_spill_alternate) f->do_form(_cisc_spill_alternate);
+  if (_short_branch_form) f->do_form(_short_branch_form);
+  _localNames.forms_do(f);
+  if (_matrule) f->do_form(_matrule);
+  if (_opcode) f->do_form(_opcode);
+  if (_insencode) f->do_form(_insencode);
+  if (_constant) f->do_form(_constant);
+  if (_attribs) f->do_form(_attribs);
+  if (_predicate) f->do_form(_predicate);
+  _effects.forms_do(f);
+  if (_exprule) f->do_form(_exprule);
+  if (_rewrule) f->do_form(_rewrule);
+  if (_format) f->do_form(_format);
+  if (_peephole) f->do_form(_peephole);
+  assert(_components.count() == 0, "skip components");
+}
+
 void MachNodeForm::dump() {
   output(stderr);
 }
@@ -1615,6 +1633,14 @@ void EncodeForm::output(FILE *fp) {          // Write info to output files
   }
   fprintf(fp,"-------------------- end  EncodeForm --------------------\n");
 }
+
+void EncodeForm::forms_do(FormClosure* f) {
+  const char *name;
+  for (_eclasses.reset(); (name = _eclasses.iter()) != nullptr;) {
+    f->do_form((EncClass*)_encClass[name]);
+  }
+}
+
 //------------------------------EncClass---------------------------------------
 EncClass::EncClass(const char *name)
   : _localNames(cmpstr,hashstr, Form::arena), _name(name) {
@@ -1705,6 +1731,15 @@ void EncClass::output(FILE *fp) {
 
 }
 
+void EncClass::forms_do(FormClosure *f) {
+  _parameter_type.reset();
+  const char *type = _parameter_type.iter();
+  for ( ; type != nullptr ; type = _parameter_type.iter() ) {
+    f->do_form_by_name(type);
+  }
+  _localNames.forms_do(f);
+}
+
 //------------------------------Opcode-----------------------------------------
 Opcode::Opcode(char *primary, char *secondary, char *tertiary)
   : _primary(primary), _secondary(secondary), _tertiary(tertiary) {
@@ -1835,6 +1870,15 @@ void InsEncode::output(FILE *fp) {
   fprintf(fp,"\n");
 }
 
+void InsEncode::forms_do(FormClosure *f) {
+  _encoding.reset();
+  NameAndList *encoding = (NameAndList*)_encoding.iter();
+  for( ; encoding != nullptr; encoding = (NameAndList*)_encoding.iter() ) {
+    // just check name, other operands will be checked as instruction parameters
+    f->do_form_by_name(encoding->name());
+  }
+}
+
 //------------------------------Effect-----------------------------------------
 static int effect_lookup(const char *name) {
   if (!strcmp(name, "USE")) return Component::USE;
@@ -1968,6 +2012,19 @@ void ExpandRule::output(FILE *fp) {         // Write info to output files
   }
 }
 
+void ExpandRule::forms_do(FormClosure *f) {
+  NameAndList *expand_instr = nullptr;
+  // Iterate over the instructions 'node' expands into
+  for(reset_instructions(); (expand_instr = iter_instructions()) != nullptr; ) {
+    f->do_form_by_name(expand_instr->name());
+  }
+  _newopers.reset();
+  const char* oper = _newopers.iter();
+  for(; oper != nullptr; oper = _newopers.iter()) {
+    f->do_form_by_name(oper);
+  }
+}
+
 //------------------------------RewriteRule------------------------------------
 RewriteRule::RewriteRule(char* params, char* block)
   : _tempParams(params), _tempBlock(block) { };  // Constructor
@@ -1984,6 +2041,12 @@ void RewriteRule::output(FILE *fp) {         // Write info to output files
           (_tempBlock?_tempBlock:""));
 }
 
+void RewriteRule::forms_do(FormClosure *f) {
+  if (_condition) f->do_form(_condition);
+  if (_instrs) f->do_form(_instrs);
+  if (_opers) f->do_form(_opers);
+}
+
 
 //==============================MachNodes======================================
 //------------------------------MachNodeForm-----------------------------------
@@ -2066,6 +2129,13 @@ void OpClassForm::output(FILE *fp) {
   fprintf(fp,"\n");
 }
 
+void OpClassForm::forms_do(FormClosure* f) {
+  const char *name;
+  for(_oplst.reset(); (name = _oplst.iter()) != nullptr;) {
+    f->do_form_by_name(name);
+  }
+}
+
 
 //==============================Operands=======================================
 //------------------------------OperandForm------------------------------------
@@ -2691,6 +2761,22 @@ void OperandForm::output(FILE *fp) {
   if (_format)     _format->dump();
 }
 
+void OperandForm::forms_do(FormClosure* f) {
+  if (_matrule)    f->do_form(_matrule);
+  if (_interface)  f->do_form(_interface);
+  if (_attribs)    f->do_form(_attribs);
+  if (_predicate)  f->do_form(_predicate);
+  if (_constraint) f->do_form(_constraint);
+  if (_construct)  f->do_form(_construct);
+  if (_format)     f->do_form(_format);
+  _localNames.forms_do(f);
+  const char* opclass = nullptr;
+  for ( _classes.reset(); (opclass = _classes.iter()) != nullptr; ) {
+    f->do_form_by_name(opclass);
+  }
+  assert(_components.count() == 0, "skip _compnets");
+}
+
 //------------------------------Constraint-------------------------------------
 Constraint::Constraint(const char *func, const char *arg)
   : _func(func), _arg(arg) {
@@ -2712,6 +2798,10 @@ void Constraint::output(FILE *fp) {           // Write info to output files
   fprintf(fp,"Constraint: %s ( %s )\n", _func, _arg);
 }
 
+void Constraint::forms_do(FormClosure *f) {
+  f->do_form_by_name(_arg);
+}
+
 //------------------------------Predicate--------------------------------------
 Predicate::Predicate(char *pr)
   : _pred(pr) {
@@ -3539,6 +3629,12 @@ void MatchNode::output(FILE *fp) {
   }
 }
 
+void MatchNode::forms_do(FormClosure *f) {
+  f->do_form_by_name(_name);
+  if (_lChild) f->do_form(_lChild);
+  if (_rChild) f->do_form(_rChild);
+}
+
 int MatchNode::needs_ideal_memory_edge(FormDict &globals) const {
   static const char *needs_ideal_memory_list[] = {
     "StoreI","StoreL","StoreP","StoreN","StoreNKlass","StoreD","StoreF" ,
@@ -3608,6 +3704,7 @@ int InstructForm::needs_base_oop_edge(FormDict &globals) const {
 }
 
 
+
 //-------------------------cisc spilling methods-------------------------------
 // helper routines and methods for detecting cisc-spilling instructions
 //-------------------------cisc_spill_merge------------------------------------
@@ -4334,6 +4431,18 @@ void MatchRule::output(FILE *fp) {
   fprintf(fp,"\n");
 }
 
+void MatchRule::forms_do(FormClosure* f) {
+  // keep sync with MatchNode::forms_do
+  f->do_form_by_name(_name);
+  if (_lChild) f->do_form(_lChild);
+  if (_rChild) f->do_form(_rChild);
+
+  // handle next rule
+  if (_next) {
+    f->do_form(_next);
+  }
+}
+
 //------------------------------Attribute--------------------------------------
 Attribute::Attribute(char *id, char* val, int type)
   : _ident(id), _val(val), _atype(type) {

src/hotspot/share/adlc/formssel.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -310,6 +310,7 @@ public:
 
   virtual void dump();             // Debug printer
   virtual void output(FILE *fp);   // Write to output files
+  virtual void forms_do(FormClosure *f);
 };
 
 //------------------------------EncodeForm-------------------------------------
@@ -333,6 +334,7 @@ public:
 
   void dump();                     // Debug printer
   void output(FILE *fp);           // Write info to output files
+  virtual void forms_do(FormClosure *f);
 };
 
 //------------------------------EncClass---------------------------------------
@@ -377,6 +379,7 @@ public:
   bool verify();
   void dump();
   void output(FILE *fp);
+  virtual void forms_do(FormClosure* f);
 };
 
 //------------------------------MachNode---------------------------------------
@@ -468,6 +471,7 @@ public:
 
   void dump();
   void output(FILE *fp);
+  virtual void forms_do(FormClosure *f);
 };
 
 //------------------------------Effect-----------------------------------------
@@ -515,6 +519,7 @@ public:
 
   void dump();                    // Debug printer
   void output(FILE *fp);          // Write info to output files
+  virtual void forms_do(FormClosure *f);
 };
 
 //---------------------------------Flag----------------------------------------
@@ -554,6 +559,7 @@ public:
   ~RewriteRule();                  // Destructor
   void dump();                     // Debug printer
   void output(FILE *fp);           // Write info to output files
+  virtual void forms_do(FormClosure* f);
 };
 
 
@@ -584,6 +590,7 @@ public:
   virtual bool ideal_only() const;
   virtual void dump();             // Debug printer
   virtual void output(FILE *fp);   // Write to output files
+  virtual void forms_do(FormClosure* f);
 };
 
 //------------------------------OperandForm------------------------------------
@@ -711,6 +718,7 @@ public:
 
   virtual void dump();             // Debug printer
   virtual void output(FILE *fp);   // Write to output files
+  virtual void forms_do(FormClosure* f);
 };
 
 //------------------------------Constraint-------------------------------------
@@ -729,6 +737,7 @@ public:
 
   void dump();                     // Debug printer
   void output(FILE *fp);           // Write info to output files
+  virtual void forms_do(FormClosure* f);
 };
 
 //------------------------------Predicate--------------------------------------
@@ -1014,6 +1023,7 @@ public:
 
   void dump();
   void output(FILE *fp);
+  virtual void forms_do(FormClosure* f);
 };
 
 //------------------------------MatchRule--------------------------------------
@@ -1075,6 +1085,7 @@ public:
   void dump();
   void output_short(FILE *fp);
   void output(FILE *fp);
+  virtual void forms_do(FormClosure* f);
 };
 
 //------------------------------Attribute--------------------------------------

src/hotspot/share/adlc/main.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -186,6 +186,9 @@ int main(int argc, char *argv[])
   // Verify that the results of the parse are consistent
   AD.verify();
 
+  // Check defined operands are used
+  AD.check_usage();
+
   // Prepare to generate the result files:
   AD.generateMatchLists();
   AD.identify_unique_operands();