gcc/m2/gm2-gcc/m2statement.cc

/* m2statement.cc provides an interface to GCC statement trees.

Copyright (C) 2012-2026 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius@glam.ac.uk>.

This file is part of GNU Modula-2.

GNU Modula-2 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GNU Modula-2 is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Modula-2; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "gcc-consolidation.h"

#include "../gm2-lang.h"
#include "../m2-tree.h"

/* Prototypes.  */

#define m2statement_c
#include "m2assert.h"
#include "m2block.h"
#include "m2decl.h"
#include "m2expr.h"
#include "m2statement.h"
#include "m2tree.h"
#include "m2treelib.h"
#include "m2type.h"
#include "m2convert.h"
#include "m2builtins.h"
#include "m2pp.h"

static GTY (()) tree param_list = NULL_TREE; /* Ready for the next time we
                                                call/define a function.  */
static GTY (()) tree last_function = NULL_TREE;


/* BuildStartFunctionCode generate function entry code.  */

void
m2statement_BuildStartFunctionCode (location_t location, tree fndecl,
                                    bool isexported, bool isinline)
{
  tree param_decl;

  ASSERT_BOOL (isexported);
  ASSERT_BOOL (isinline);
  /* Announce we are compiling this function.  */
  announce_function (fndecl);

  /* Set up to compile the function and enter it.  */

  DECL_INITIAL (fndecl) = NULL_TREE;

  current_function_decl = fndecl;
  m2block_pushFunctionScope (fndecl);
  m2statement_SetBeginLocation (location);

  ASSERT_BOOL ((cfun != NULL));
  /* Initialize the RTL code for the function.  */
  allocate_struct_function (fndecl, false);
  /* Begin the statement tree for this function.  */
  DECL_SAVED_TREE (fndecl) = NULL_TREE;

  /* Set the context of these parameters to this function.  */
  for (param_decl = DECL_ARGUMENTS (fndecl); param_decl;
       param_decl = TREE_CHAIN (param_decl))
    DECL_CONTEXT (param_decl) = fndecl;

  /* This function exists in static storage.  (This does not mean
  `static' in the C sense!) */
  TREE_STATIC (fndecl) = 1;
  TREE_PUBLIC (fndecl) = isexported;
  /* We could do better here by detecting ADR
     or type PROC used on this function.  --fixme--  */
  TREE_ADDRESSABLE (fndecl) = 1;
  DECL_DECLARED_INLINE_P (fndecl) = 0; /* isinline;  */
}

/* BuildEndFunctionCode generates the function epilogue.  */

void
m2statement_BuildEndFunctionCode (location_t location, tree fndecl, bool nested)
{
  tree block = DECL_INITIAL (fndecl);

  BLOCK_SUPERCONTEXT (block) = fndecl;

  /* Must mark the RESULT_DECL as being in this function.  */
  DECL_CONTEXT (DECL_RESULT (fndecl)) = fndecl;

  /* And attach it to the function.  */
  DECL_INITIAL (fndecl) = block;

  m2block_finishFunctionCode (fndecl);
  m2statement_SetEndLocation (location);

  m2pp_dump_gimple (M2PP_DUMP_PRE_GENERICIZE, fndecl);
  gm2_genericize (fndecl);
  if (nested)
    (void)cgraph_node::get_create (fndecl);
  else
    {
      m2pp_dump_gimple (M2PP_DUMP_POST_GENERICIZE, fndecl);
      cgraph_node::finalize_function (fndecl, false);
    }

  m2block_popFunctionScope ();

  /* We're leaving the context of this function, so zap cfun.  It's
     still in DECL_STRUCT_FUNCTION, and we'll restore it in
     tree_rest_of_compilation.  */
  set_cfun (NULL);
  current_function_decl = NULL;
}

/* BuildPushFunctionContext pushes the current function context.
   Maps onto push_function_context in ../function.cc.  */

void
m2statement_BuildPushFunctionContext (void)
{
  push_function_context ();
}

/* BuildPopFunctionContext pops the current function context.  Maps
   onto pop_function_context in ../function.cc.  */

void
m2statement_BuildPopFunctionContext (void)
{
  pop_function_context ();
}

void
m2statement_SetBeginLocation (location_t location)
{
  if (cfun != NULL)
    cfun->function_start_locus = location;
}

void
m2statement_SetEndLocation (location_t location)
{
  if (cfun != NULL)
    cfun->function_end_locus = location;
}

/* copy_record_fields copy each record field from right to left.  */

static
void
copy_record_fields (location_t location, tree left, tree right)
{
  unsigned int i;
  tree right_value;
  tree left_type = TREE_TYPE (left);
  vec<constructor_elt, va_gc> *values = CONSTRUCTOR_ELTS (right);
  FOR_EACH_CONSTRUCTOR_VALUE (values, i, right_value)
    {
      tree left_field = m2treelib_get_field_no (left_type, NULL_TREE, false, i);
      tree left_ref = m2expr_BuildComponentRef (location, left, left_field);
      m2statement_CopyByField (location, left_ref, right_value);
    }
}

/* copy_array copy each element of an array from array right to array left.  */

static
void
copy_array (location_t location, tree left, tree right)
{
  unsigned int i;
  tree value;
  vec<constructor_elt, va_gc> *values = CONSTRUCTOR_ELTS (right);
  tree array_type = TREE_TYPE (left);
  tree index_type = TYPE_DOMAIN (array_type);
  tree elt_type = TREE_TYPE (array_type);
  tree low_indice = TYPE_MIN_VALUE (index_type);
  low_indice
      = m2convert_BuildConvert (location, index_type, low_indice, false);
  FOR_EACH_CONSTRUCTOR_VALUE (values, i, value)
    {
      tree idx = m2decl_BuildIntegerConstant (i);
      idx = m2convert_BuildConvert (location, index_type, idx, false);
      tree array_ref = build4_loc (location, ARRAY_REF, elt_type, left,
				   idx, low_indice, NULL_TREE);
      m2statement_CopyByField (location, array_ref, value);
    }
}

/* copy_array cst into left using strncpy.  */

static
void
copy_strncpy (location_t location, tree left, tree cst)
{
  tree result = m2builtins_BuiltinStrNCopy (location,
					    m2expr_BuildAddr (location, left, false),
					    m2expr_BuildAddr (location, cst, false),
					    m2decl_BuildIntegerConstant (m2expr_StringLength (cst)));
  TREE_SIDE_EFFECTS (result) = true;
  TREE_USED (left) = true;
  TREE_USED (cst) = true;
  add_stmt (location, result);
}

/* CopyMemcpy copy bytes from src into dest using builtin_memcpy.  */

void
m2statement_CopyMemcpy (location_t location, tree dest, tree src, tree bytes)
{
  tree addr_dest = m2expr_BuildAddr (location, dest, false);
  tree result = m2builtins_BuiltinMemCopy (location,
					   addr_dest,
					   m2expr_BuildAddr (location, src, false),
					   bytes);
  TREE_SIDE_EFFECTS (result) = true;
  TREE_USED (dest) = true;
  TREE_USED (src) = true;
  add_stmt (location, result);
}

/* CopyByField_Lower copy right to left using memcpy for unions,
   strncpy for string cst, field assignment for records,
   array element assignment for array constructors.  For all
   other types it uses BuildAssignmentStatement.  */

static
void
CopyByField_Lower (location_t location,
		   tree left, tree right)
{
  tree left_type = TREE_TYPE (left);
  enum tree_code right_code = TREE_CODE (right);
  enum tree_code left_code = TREE_CODE (left_type);

  if (left_code == RECORD_TYPE && right_code == CONSTRUCTOR)
    copy_record_fields (location, left, right);
  else if (left_code == ARRAY_TYPE && right_code == CONSTRUCTOR)
    copy_array (location, left, right);
  else if (left_code == UNION_TYPE && right_code == CONSTRUCTOR)
    m2statement_CopyMemcpy (location, left, right,
			    m2expr_GetSizeOf (location, left));
  else if (right_code == STRING_CST)
    copy_strncpy (location, left, right);
  else
    m2statement_BuildAssignmentStatement (location, left, right);
}

/* CopyByField recursively checks each field to ensure GCC
   type equivalence and if so it uses assignment.
   Otherwise use strncpy or memcpy depending upon type.  */

void
m2statement_CopyByField (location_t location, tree des, tree expr)
{
  if (m2type_IsGccStrictTypeEquivalent (des, expr))
    m2statement_BuildAssignmentStatement (location, des, expr);
  else
    CopyByField_Lower (location, des, expr);
}

/* BuildAssignmentTree builds the assignment of des and expr.
   It returns des.  */

void
m2statement_BuildAssignmentTree (location_t location, tree des, tree expr)
{
  tree result;

  m2assert_AssertLocation (location);
  STRIP_TYPE_NOPS (expr);

  if (TREE_CODE (expr) == FUNCTION_DECL)
    result = build2 (MODIFY_EXPR, TREE_TYPE (des), des,
                     m2expr_BuildAddr (location, expr, false));
  else
    {
      gcc_assert (TREE_CODE (TREE_TYPE (des)) != TYPE_DECL);
      if ((TREE_CODE (expr) == CONSTRUCTOR)
	  && (TREE_CODE (TREE_TYPE (des)) == ARRAY_TYPE))
	{
	  m2statement_CopyMemcpy (location, des, expr,
				  m2expr_GetSizeOf (location,
						    m2type_GetTreeType (des)));
	  return;
	}
      else if (TREE_TYPE (expr) == TREE_TYPE (des))
        result = build2 (MODIFY_EXPR, TREE_TYPE (des), des, expr);
      else
        result = build2 (
            MODIFY_EXPR, TREE_TYPE (des), des,
            m2convert_BuildConvert (location, TREE_TYPE (des), expr, false));
    }

  TREE_SIDE_EFFECTS (result) = true;
  TREE_USED (des) = true;
  TREE_USED (expr) = true;
  add_stmt (location, result);
}

/* BuildAssignmentStatement builds the assignment of des and expr.  */

void
m2statement_BuildAssignmentStatement (location_t location, tree des, tree expr)
{
  m2statement_BuildAssignmentTree (location, des, expr);
}

/* BuildGoto builds a goto operation.  */

void
m2statement_BuildGoto (location_t location, char *name)
{
  tree label = m2block_getLabel (location, name);

  m2assert_AssertLocation (location);
  TREE_USED (label) = true;
  add_stmt (location, build1 (GOTO_EXPR, void_type_node, label));
}

/* DeclareLabel create a label, name.  */

void
m2statement_DeclareLabel (location_t location, char *name)
{
  tree label = m2block_getLabel (location, name);

  m2assert_AssertLocation (location);
  add_stmt (location, build1 (LABEL_EXPR, void_type_node, label));
}

/* BuildParam build a list of parameters, ready for a subsequent
   procedure call.  */

void
m2statement_BuildParam (location_t location, tree param)
{
  m2assert_AssertLocation (location);

  TREE_USED (param) = true;
  if (TREE_CODE (param) == FUNCTION_DECL)
    param = m2expr_BuildAddr (location, param, false);

  param_list = chainon (build_tree_list (NULL_TREE, param), param_list);
}

/* nCount return the number of chained tree nodes in list, t.  */

static int
nCount (tree t)
{
  int i = 0;

  while (t != NULL)
    {
      i++;
      t = TREE_CHAIN (t);
    }
  return i;
}

/* BuildProcedureCallTree creates a procedure call from a procedure
   and parameter list and the return type, rettype.  */

tree
m2statement_BuildProcedureCallTree (location_t location, tree procedure,
                                    tree rettype)
{
  tree functype = TREE_TYPE (procedure);
  tree funcptr = build1 (ADDR_EXPR, build_pointer_type (functype), procedure);
  tree call;
  int n = nCount (param_list);
  tree *argarray = XALLOCAVEC (tree, n);
  tree t = param_list;
  int i;

  m2assert_AssertLocation (location);
  ASSERT_CONDITION (
      last_function
      == NULL_TREE); /* Previous function value has not been collected.  */
  TREE_USED (procedure) = true;

  for (i = 0; i < n; i++)
    {
      argarray[i] = TREE_VALUE (t);
      t = TREE_CHAIN (t);
    }

  if (rettype == NULL_TREE)
    {
      rettype = void_type_node;
      call = build_call_array_loc (location, rettype, funcptr, n, argarray);
      TREE_USED (call) = true;
      TREE_SIDE_EFFECTS (call) = true;

#if defined(DEBUG_PROCEDURE_CALLS)
      fprintf (stderr, "built the modula-2 call, here is the tree\n");
      fflush (stderr);
      debug_tree (call);
#endif

      param_list
          = NULL_TREE; /* Ready for the next time we call a procedure.  */
      last_function = NULL_TREE;
      return call;
    }
  else
    {
      last_function = build_call_array_loc (
          location, m2tree_skip_type_decl (rettype), funcptr, n, argarray);
      TREE_USED (last_function) = true;
      TREE_SIDE_EFFECTS (last_function) = true;
      param_list
          = NULL_TREE; /* Ready for the next time we call a procedure.  */
      return last_function;
    }
}

/* BuildIndirectProcedureCallTree creates a procedure call from a
   procedure and parameter list and the return type, rettype.  */

tree
m2statement_BuildIndirectProcedureCallTree (location_t location,
                                            tree procedure, tree rettype)
{
  tree call;
  int n = nCount (param_list);
  tree *argarray = XALLOCAVEC (tree, n);
  tree t = param_list;
  int i;

  m2assert_AssertLocation (location);
  TREE_USED (procedure) = true;
  TREE_SIDE_EFFECTS (procedure) = true;

  for (i = 0; i < n; i++)
    {
      argarray[i] = TREE_VALUE (t);
      t = TREE_CHAIN (t);
    }

  if (rettype == NULL_TREE)
    {
      rettype = void_type_node;
      call = build_call_array_loc (location, rettype, procedure, n, argarray);
      TREE_USED (call) = true;
      TREE_SIDE_EFFECTS (call) = true;

#if defined(DEBUG_PROCEDURE_CALLS)
      fprintf (stderr, "built the modula-2 call, here is the tree\n");
      fflush (stderr);
      debug_tree (call);
#endif

      last_function = NULL_TREE;
      param_list
          = NULL_TREE; /* Ready for the next time we call a procedure.  */
      return call;
    }
  else
    {
      last_function = build_call_array_loc (
          location, m2tree_skip_type_decl (rettype), procedure, n, argarray);
      TREE_USED (last_function) = true;
      TREE_SIDE_EFFECTS (last_function) = true;
      param_list
          = NULL_TREE; /* Ready for the next time we call a procedure.  */
      return last_function;
    }
}


/* BuildBuiltinCallTree calls the builtin procedure.  */

tree
m2statement_BuildBuiltinCallTree (tree func)
{
  TREE_USED (func) = true;
  TREE_SIDE_EFFECTS (func) = true;
  param_list
    = NULL_TREE; /* Ready for the next time we call a procedure.  */
  return func;
}


/* BuildFunctValue generates code for
   value := last_function (foobar).  */

tree
m2statement_BuildFunctValue (location_t location, tree value)
{
  tree assign
      = m2treelib_build_modify_expr (location, value, NOP_EXPR, last_function);

  m2assert_AssertLocation (location);
  ASSERT_CONDITION (
      last_function
      != NULL_TREE);  /* No value available, possible used before.  */

  TREE_SIDE_EFFECTS (assign) = true;
  TREE_USED (assign) = true;
  TREE_USED (value) = true;
  last_function = NULL_TREE;
  return assign;
}

/* BuildCall2 builds a tree representing: function (arg1, arg2).  */

tree
m2statement_BuildCall2 (location_t location, tree function, tree rettype,
                        tree arg1, tree arg2)
{
  m2assert_AssertLocation (location);
  ASSERT_CONDITION (param_list == NULL_TREE);

  param_list = chainon (build_tree_list (NULL_TREE, arg2), param_list);
  param_list = chainon (build_tree_list (NULL_TREE, arg1), param_list);
  return m2statement_BuildProcedureCallTree (location, function, rettype);
}

/* BuildCall3 builds a tree representing: function (arg1, arg2, arg3).  */

tree
m2statement_BuildCall3 (location_t location, tree function, tree rettype,
                        tree arg1, tree arg2, tree arg3)
{
  m2assert_AssertLocation (location);
  ASSERT_CONDITION (param_list == NULL_TREE);

  param_list = chainon (build_tree_list (NULL_TREE, arg3), param_list);
  param_list = chainon (build_tree_list (NULL_TREE, arg2), param_list);
  param_list = chainon (build_tree_list (NULL_TREE, arg1), param_list);
  return m2statement_BuildProcedureCallTree (location, function, rettype);
}

/* BuildFunctionCallTree creates a procedure function call from
   a procedure and parameter list and the return type, rettype.
   No tree is returned as the tree is held in the last_function global
   variable.  It is expected the BuildFunctValue is to be called after
   a call to BuildFunctionCallTree.  */

void
m2statement_BuildFunctionCallTree (location_t location, tree procedure,
                                   tree rettype)
{
  m2statement_BuildProcedureCallTree (location, procedure, rettype);
}

/* SetLastFunction assigns last_function to, t.  */

void
m2statement_SetLastFunction (tree t)
{
  last_function = t;
}

/* SetParamList assigns param_list to, t.  */

void
m2statement_SetParamList (tree t)
{
  param_list = t;
}

/* GetLastFunction returns, last_function.  */

tree
m2statement_GetLastFunction (void)
{
  return last_function;
}

/* GetParamList returns, param_list.  */

tree
m2statement_GetParamList (void)
{
  return param_list;
}

/* GetCurrentFunction returns the current_function.  */

tree
m2statement_GetCurrentFunction (void)
{
  return current_function_decl;
}

/* GetParamTree return parameter, i.  */

tree
m2statement_GetParamTree (tree call, unsigned int i)
{
  return CALL_EXPR_ARG (call, i);
}

/* BuildTryFinally returns a TRY_FINALL_EXPR with the call and
   cleanups attached.  */

tree
m2statement_BuildTryFinally (location_t location, tree call, tree cleanups)
{
  return build_stmt (location, TRY_FINALLY_EXPR, call, cleanups);
}

/* BuildCleanUp return a CLEANUP_POINT_EXPR which will clobber,
   param.  */

tree
m2statement_BuildCleanUp (tree param)
{
  tree clobber = build_constructor (TREE_TYPE (param), NULL);
  TREE_THIS_VOLATILE (clobber) = 1;
  return build2 (MODIFY_EXPR, TREE_TYPE (param), param, clobber);
}

/* BuildAsm generates an inline assembler instruction.  */

void
m2statement_BuildAsm (location_t location, tree instr, bool isVolatile,
                      bool isSimple, tree inputs, tree outputs, tree trash,
                      tree labels)
{
  tree string = resolve_asm_operand_names (instr, outputs, inputs, labels);
  tree args = build_stmt (location, ASM_EXPR, string, outputs, inputs, trash,
                          labels);

  m2assert_AssertLocation (location);

  /* ASM statements without outputs, including simple ones, are treated
     as volatile.  */
  ASM_BASIC_P (args) = isSimple;
  ASM_VOLATILE_P (args) = isVolatile;

  add_stmt (location, args);
}

/* BuildStart creates a module initialization function.  We make
   this function public if it is not an inner module.  The linker
   will create a call list for all linked modules which determines
   the initialization sequence for all modules.  */

tree
m2statement_BuildStart (location_t location, char *name, bool inner_module)
{
  tree fntype;
  tree fndecl;

  m2assert_AssertLocation (location);
  /* The function type depends on the return type and type of args.  */
  fntype = build_function_type (integer_type_node, NULL_TREE);
  fndecl = build_decl (location, FUNCTION_DECL, get_identifier (name), fntype);

  DECL_EXTERNAL (fndecl) = 0;
  if (inner_module)
    TREE_PUBLIC (fndecl) = 0;
  else
    TREE_PUBLIC (fndecl) = 1;

  TREE_STATIC (fndecl) = 1;
  DECL_RESULT (fndecl)
      = build_decl (location, RESULT_DECL, NULL_TREE, integer_type_node);
  DECL_CONTEXT (DECL_RESULT (fndecl)) = fndecl;

  /* Prevent the optimizer from removing it if it is public.  */
  if (TREE_PUBLIC (fndecl))
    gm2_mark_addressable (fndecl);

  m2statement_BuildStartFunctionCode (location, fndecl, !inner_module,
                                      inner_module);
  return fndecl;
}

/* BuildEnd complete the initialization function for this module.  */

void
m2statement_BuildEnd (location_t location, tree fndecl, bool nested)
{
  m2statement_BuildEndFunctionCode (location, fndecl, nested);
  current_function_decl = NULL;
  set_cfun (NULL);
}

/* BuildCallInner call the inner module function.  It has no
   parameters and no return value.  */

void
m2statement_BuildCallInner (location_t location, tree fndecl)
{
  m2assert_AssertLocation (location);
  param_list = NULL_TREE;
  add_stmt (location,
            m2statement_BuildProcedureCallTree (location, fndecl, NULL_TREE));
}


/* BuildIfThenDoEnd returns a tree which will only execute
   statement, s, if, condition, is true.  */

tree
m2statement_BuildIfThenDoEnd (tree condition, tree then_block)
{
  if (then_block == NULL_TREE)
    return NULL_TREE;
  else
    return fold_build3 (COND_EXPR, void_type_node, condition, then_block,
                        alloc_stmt_list ());
}

/* BuildIfThenElseEnd returns a tree which will execute then_block
   or else_block depending upon, condition.  */

tree
m2statement_BuildIfThenElseEnd (tree condition, tree then_block,
                                tree else_block)
{
  if (then_block == NULL_TREE)
    return NULL_TREE;
  else
    return fold_build3 (COND_EXPR, void_type_node, condition, then_block,
                        else_block);
}

/* BuildReturnValueCode generates the code associated with:
   RETURN ( value ).  */

void
m2statement_BuildReturnValueCode (location_t location, tree fndecl, tree value)
{
  tree ret_stmt;
  tree t;

  m2assert_AssertLocation (location);
  t = build2 (
      MODIFY_EXPR, TREE_TYPE (DECL_RESULT (fndecl)), DECL_RESULT (fndecl),
      m2convert_BuildConvert (
          location, m2tree_skip_type_decl (TREE_TYPE (DECL_RESULT (fndecl))),
          value, false));

  ret_stmt = build_stmt (location, RETURN_EXPR, t);
  add_stmt (location, ret_stmt);
}

/* IfExprJump if expr then jump to the label.  */

void
m2statement_IfExprJump (location_t location, tree exp, char *label)
{
  tree if_jump;

  m2assert_AssertLocation (location);
  if (TREE_CODE (TREE_TYPE (exp)) != BOOLEAN_TYPE)
    exp = convert_loc (location, m2type_GetBooleanType (), exp);

  m2block_push_statement_list (m2block_begin_statement_list ());
  m2statement_BuildGoto (location, label);
  if_jump = build3 (COND_EXPR, void_type_node, exp,
		    m2block_pop_statement_list (),
		    alloc_stmt_list ());
  add_stmt (location, if_jump);
}


/* IfBitInSetJump if bit in set jump to label.  */

void
m2statement_IfBitInSetJump (location_t location, bool invertCondition,
			    tree setvalue, tree bit, char *label)
{
  tree condition;

  condition = m2expr_BuildNotEqualTo (location,
				      m2expr_BuildLogicalAnd (location,
							      m2expr_BuildLSL (location,
									       m2expr_GetWordOne (location),
									       bit, false),
							      setvalue),
				      m2expr_GetWordZero (location)) ;
  if (invertCondition)
    condition = m2expr_BuildEqualTo (location, condition,
				     m2type_GetBooleanFalse ());
  m2statement_IfExprJump (location, condition, label);
}

#include "gt-m2-m2statement.h"