396 lines
7.7 KiB
C
396 lines
7.7 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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/* Lint miscellaneous routines */
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#include "lint.h"
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#ifdef LINT
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#include <alloc.h> /* for st_free */
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#include "interface.h"
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#include "arith.h" /* definition arith */
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#include "label.h" /* definition label */
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#include "expr.h"
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#include "idf.h"
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#include "def.h"
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#include "code.h" /* RVAL etc */
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#include "LLlex.h"
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#include "Lpars.h"
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#include "stack.h"
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#include "type.h"
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#include "level.h"
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#include "nofloat.h"
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#include "l_state.h"
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extern char *symbol2str();
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extern struct type *func_type;
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PRIVATE lint_enum_arith();
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PRIVATE lint_conversion();
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PRIVATE int numsize();
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lint_new_oper(expr)
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struct expr *expr;
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{
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/* Does additional checking on a newly constructed expr node
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of class Oper.
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Some code in this routine could be contracted, but since
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I am not sure we have covered the entire ground, we'll
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leave the contracting for some rainy day.
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*/
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register struct expr *left = expr->OP_LEFT;
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register struct expr *right = expr->OP_RIGHT;
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register int oper = expr->OP_OPER;
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register int l_fund =
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left == 0 ? 0 : /* for monadics */
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left->ex_type->tp_fund;
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register int r_fund =
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right == 0 ? 0 : /* for ( without parameters */
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right->ex_type->tp_fund;
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/* In ch7.c, in ch7asgn(), a combined operator/assignment
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is hammered into correctness by repeated application of
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ch7bin(), which calls new_oper(), which calls lint_new_oper().
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These spurious calls understandably cause spurious error
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messages, which we don't like. So we try to suppress these
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wierd calls here. This refers to the code marked
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this is really $#@&*%$# !
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in ch7asgn().
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*/
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switch (oper) {
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case PLUSAB:
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case MINAB:
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case TIMESAB:
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case DIVAB:
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case MODAB:
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case LEFTAB:
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case RIGHTAB:
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case ANDAB:
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case XORAB:
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case ORAB:
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/* is the left operand wierd? */
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if ( left->ex_class == Value
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&& left->VL_CLASS == Const
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&& left->VL_VALUE == 0
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) {
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return;
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}
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}
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switch (oper) {
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case '=':
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lint_conversion(right, l_fund);
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break;
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case PLUSAB:
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lint_conversion(right, l_fund);
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case '+':
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lint_enum_arith(l_fund, oper, r_fund);
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break;
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case MINAB:
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lint_conversion(right, l_fund);
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case '-':
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if (left == 0) {
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/* unary */
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if (r_fund == ENUM)
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warning("negating an enum");
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}
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else {
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/* binary */
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if (l_fund == ENUM && r_fund == ENUM) {
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if (!equal_type(left->ex_type, right->ex_type))
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warning("subtracting enums of different type");
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/* update the type, cem does not do it */
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expr->ex_type = int_type;
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}
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lint_enum_arith(l_fund, oper, r_fund);
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}
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break;
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case TIMESAB:
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lint_conversion(right, l_fund);
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case '*':
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if (left == 0) {
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/* unary */
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}
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else {
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/* binary */
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if (l_fund == ENUM || r_fund == ENUM)
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warning("multiplying enum");
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}
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break;
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case DIVAB:
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lint_conversion(right, l_fund);
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case '/':
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if (l_fund == ENUM || r_fund == ENUM)
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warning("division on enum");
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break;
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case MODAB:
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lint_conversion(right, l_fund);
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case '%':
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if (l_fund == ENUM || r_fund == ENUM)
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warning("modulo on enum");
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break;
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case '~':
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if (r_fund == ENUM || r_fund == FLOAT || r_fund == DOUBLE)
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warning("~ on %s", symbol2str(r_fund));
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break;
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case '!':
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if (r_fund == ENUM)
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warning("! on enum");
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break;
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case INT2INT:
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case INT2FLOAT:
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case FLOAT2INT:
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case FLOAT2FLOAT:
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lint_conversion(right, l_fund);
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break;
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case '<':
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case '>':
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case LESSEQ:
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case GREATEREQ:
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case EQUAL:
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case NOTEQUAL:
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if ( (l_fund == ENUM || r_fund == ENUM)
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&& !equal_type(left->ex_type, right->ex_type)
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) {
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warning("comparing enum with non-enum");
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}
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lint_relop(left, right, oper);
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lint_relop(right, left,
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oper == '<' ? '>' :
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oper == '>' ? '<' :
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oper == LESSEQ ? GREATEREQ :
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oper == GREATEREQ ? LESSEQ :
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oper
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);
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break;
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case LEFTAB:
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case RIGHTAB:
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lint_conversion(right, l_fund);
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case LEFT:
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case RIGHT:
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if (l_fund == ENUM || r_fund == ENUM)
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warning("shift on enum");
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break;
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case ANDAB:
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case ORAB:
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case XORAB:
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lint_conversion(right, l_fund);
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case '&':
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case '|':
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case '^':
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if (l_fund == ENUM || r_fund == ENUM)
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warning("bit operations on enum");
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break;
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case ',':
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case '?':
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case ':':
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case AND:
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case OR:
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case POSTINCR:
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case POSTDECR:
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case PLUSPLUS:
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case MINMIN:
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case '(':
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case '.':
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case ARROW:
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default:
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/* OK with lint */
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break;
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}
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}
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PRIVATE
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lint_enum_arith(l_fund, oper, r_fund)
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int l_fund, oper, r_fund;
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{
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if ( l_fund == ENUM
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&& r_fund != CHAR
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&& r_fund != SHORT
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&& r_fund != INT
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) {
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warning("%s on enum and %s",
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symbol2str(oper), symbol2str(r_fund));
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}
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else
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if ( r_fund == ENUM
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&& l_fund != CHAR
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&& l_fund != SHORT
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&& l_fund != INT
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) {
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warning("%s on %s and enum",
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symbol2str(oper), symbol2str(l_fund));
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}
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}
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PRIVATE
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lint_conversion(from_expr, to_fund)
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struct expr *from_expr;
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int to_fund;
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{
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register int from_fund = from_expr->ex_type->tp_fund;
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/* was there an attempt to reduce the type of the from_expr
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of the form
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expr & 0377
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or something like this?
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*/
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if (from_expr->ex_class == Oper && from_expr->OP_OPER == INT2INT) {
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from_expr = from_expr->OP_LEFT;
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}
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if (from_expr->ex_class == Oper && from_expr->OP_OPER == '&') {
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struct expr *bits =
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is_cp_cst(from_expr->OP_LEFT) ? from_expr->OP_LEFT :
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is_cp_cst(from_expr->OP_RIGHT) ? from_expr->OP_RIGHT :
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0;
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if (bits) {
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arith val = bits->VL_VALUE;
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if (val < 256)
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from_fund = CHAR;
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else if (val < 256)
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from_fund = SHORT;
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}
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}
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if (numsize(from_fund) > numsize(to_fund)) {
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awarning("conversion from %s to %s may lose accuracy",
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symbol2str(from_fund), symbol2str(to_fund));
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}
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}
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PRIVATE int
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numsize(fund)
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{
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switch (fund) {
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case CHAR: return 1;
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case SHORT: return 2;
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case INT: return 3;
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case ENUM: return 3;
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case LONG: return 4;
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case FLOAT: return 5;
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case DOUBLE: return 6;
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default: return 0;
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}
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}
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lint_ret_conv(from_expr)
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struct expr *from_expr;
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{
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lint_conversion(from_expr, func_type->tp_fund);
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}
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lint_ptr_conv(from, to)
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short from, to;
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{
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/* X -> X ok -- this includes struct -> struct, of any size
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* X -> CHAR ok
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* DOUBLE -> X ok
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* FLOAT -> LONG -> INT -> SHORT ok
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*/
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if (from == to)
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return;
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if (to == CHAR)
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return;
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if (from == DOUBLE)
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return;
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switch (from) {
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case FLOAT:
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switch (to) {
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case LONG:
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case INT:
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case SHORT:
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return;
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}
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break;
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case LONG:
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switch (to) {
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case INT:
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case SHORT:
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return;
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}
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break;
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case INT:
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switch (to) {
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case SHORT:
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return;
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}
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break;
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}
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if (from == CHAR) {
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hwarning("pointer to char may not align correctly for a %s",
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symbol2str(to));
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}
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else {
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warning("pointer to %s may not align correctly for a %s",
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symbol2str(from), symbol2str(to));
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}
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}
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lint_relop(left, right, oper)
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struct expr *left, *right;
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int oper; /* '<', '>', LESSEQ, GREATEREQ, EQUAL, NOTEQUAL */
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{
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/* left operand may be converted */
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if ( left->ex_class == Oper
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&& left->OP_OPER == INT2INT
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) {
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left = left->OP_RIGHT;
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}
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/* <unsigned> <relop> <neg-const|0> is doubtful */
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if ( left->ex_type->tp_unsigned
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&& right->ex_class == Value
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&& right->VL_CLASS == Const
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) {
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if (right->VL_VALUE < 0) {
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warning("unsigned compared to negative constant");
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}
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if (right->VL_VALUE == 0) {
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switch (oper) {
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case '<':
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warning("unsigned < 0 will always fail");
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break;
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case LESSEQ:
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warning("unsigned <= 0 is probably wrong");
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break;
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case GREATEREQ:
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warning("unsigned >= 0 will always succeed");
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break;
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}
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}
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}
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/* <char> <relop> <neg-const> is undefined */
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if ( left->ex_type->tp_fund == CHAR
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&& right->ex_class == Value
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&& right->VL_CLASS == Const
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&& (right->VL_VALUE < 0 || right->VL_VALUE > 127)
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) {
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warning("character compared to negative constant");
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}
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}
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#endif LINT
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