compilerplugins/clang/literalalternative.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #include <string>
  11
  12 #include "plugin.hxx"
  13
  14 // Find those calls of rtl::OUString::equalsIgnoreAsciiCaseAscii and
  15 // rtl::OUString::equalsIgnoreAsciiCaseAsciiL that could be simplified to call
  16 // rtl::OUString::equalsIgnoreAsciiCase instead:
  17
  18 namespace {
  19
  20 class LiteralAlternative:
  21     public RecursiveASTVisitor<LiteralAlternative>, public loplugin::Plugin
  22 {
  23 public:
  24     explicit LiteralAlternative(CompilerInstance & compiler): Plugin(compiler) {}
  25
  26     virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  27
  28     bool VisitCallExpr(const CallExpr * expr);
  29 };
  30
  31 bool LiteralAlternative::VisitCallExpr(const CallExpr * expr) {
  32     if (ignoreLocation(expr)) {
  33         return true;
  34     }
  35     FunctionDecl const * fdecl = expr->getDirectCallee();
  36     if (fdecl == nullptr) {
  37         return true;
  38     }
  39     std::string qname { fdecl->getQualifiedNameAsString() };
  40     if (qname == "rtl::OUString::equalsIgnoreAsciiCaseAscii"
  41         && fdecl->getNumParams() == 1 && expr->getNumArgs() == 1)
  42     {
  43         // equalsIgnoreAsciiCaseAscii("foo") -> equalsIngoreAsciiCase("foo"):
  44         StringLiteral const * lit
  45             = dyn_cast<StringLiteral>(expr->getArg(0)->IgnoreParenImpCasts());
  46         if (lit != nullptr) {
  47             report(
  48                 DiagnosticsEngine::Warning,
  49                 ("rewrite call of rtl::OUString::equalsIgnoreAsciiCaseAscii"
  50                  " with string literal argument as call of"
  51                  " rtl::OUString::equalsIgnoreAsciiCase"),
  52                 expr->getExprLoc());
  53                 //TODO: a better loc (the "equalsIgnoreAsciiCaseAscii" part)?
  54         }
  55         return true;
  56     }
  57     if (qname == "rtl::OUString::equalsIgnoreAsciiCaseAsciiL"
  58         && fdecl->getNumParams() == 2 && expr->getNumArgs() == 2)
  59     {
  60         // equalsIgnoreAsciiCaseAsciiL("foo", 3) -> equalsIngoreAsciiCase("foo")
  61         // especially also for
  62         // equalsIgnoreAsciiCaseAsciiL(RTL_CONSTASCII_STRINGPARAM("foo")), where
  63         // RTL_CONSTASCII_STRINGPARAM expands to complicated expressions
  64         // involving (&(X)[0] sub-expressions (and it might or might not be
  65         // better to handle that at the level of non-expanded macros instead,
  66         // but I have not found out how to do that yet anyway):
  67         APSInt res;
  68         if (expr->getArg(1)->isIntegerConstantExpr(res, compiler.getASTContext())) {
  69             Expr const * arg0 = expr->getArg(0)->IgnoreParenImpCasts();
  70             StringLiteral const * lit = dyn_cast<StringLiteral>(arg0);
  71             bool match = false;
  72             if (lit != nullptr) {
  73                 match = res == lit->getLength();
  74             } else {
  75                 UnaryOperator const * op = dyn_cast<UnaryOperator>(arg0);
  76                 if (op != nullptr && op->getOpcode() == UO_AddrOf) {
  77                     ArraySubscriptExpr const * subs
  78                         = dyn_cast<ArraySubscriptExpr>(
  79                             op->getSubExpr()->IgnoreParenImpCasts());
  80                     if (subs != nullptr) {
  81                         lit = dyn_cast<StringLiteral>(
  82                             subs->getBase()->IgnoreParenImpCasts());
  83                         match = lit != nullptr
  84                             && subs->getIdx()->isIntegerConstantExpr(
  85                                 res, compiler.getASTContext())
  86                             && res == 0;
  87                     }
  88                 }
  89             }
  90             if (match) {
  91                 report(
  92                     DiagnosticsEngine::Warning,
  93                     ("rewrite call of"
  94                      " rtl::OUString::equalsIgnoreAsciiCaseAsciiL with string"
  95                      " literal and matching length arguments as call of"
  96                      " rtl::OUString::equalsIgnoreAsciiCase"),
  97                     expr->getExprLoc());
  98                     //TODO: a better loc (the "equalsIgnoreAsciiCaseAsciiL"
  99                     // part)?
 100             }
 101         }
 102         return true;
 103     }
 104     return true;
 105 }
 106
 107 loplugin::Plugin::Registration< LiteralAlternative > X("literalalternative");
 108
 109 }
 110
 111 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */