[PATCH] D150895: [NFC][CLANG] Fix dereference issue before null check found by Coverity static analyzer tool

[Soumi Manna via Phabricator via cfe-commits]

Manna created this revision.
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Herald added subscribers: manas, ASDenysPetrov, luismarques, s.egerton, dkrupp, 
donat.nagy, Szelethus, PkmX, a.sidorin, simoncook, baloghadamsoftware, 
arichardson.
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Manna requested review of this revision.
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Herald added a project: clang.

Reported by Coverity static analyzer tool:

  Inside "ParsePragma.cpp" file, in 
<unnamed>::​PragmaRISCVHandler::​HandlePragma(clang::​Preprocessor &, 
clang::​PragmaIntroducer, clang::​Token &): All paths that lead to this null 
pointer comparison already dereference the pointer earlier
  
  PP.Lex(Tok);
  II = Tok.getIdentifierInfo();
  //deref_ptr_in_call: Dereferencing pointer II. 
  StringRef IntrinsicClass = II->getName();
        
  //Dereference before null check (REVERSE_INULL)
  //check_after_deref: Null-checking II suggests that it may be null, but it 
has already been dereferenced on all paths leading to the check.
    if (!II || !(II->isStr("vector") || II->isStr("sifive_vector"))) {
      PP.Diag(Tok.getLocation(), diag::warn_pragma_invalid_argument)
          << PP.getSpelling(Tok) << "riscv" << /*Expected=*/true
          << "'vector' or 'sifive_vector'";
      return;
  }

This removes duplicate code and moves the line `StringRef IntrinsicClass = 
II->getName()` after null checking `II`


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D150895

Files:
  clang/lib/Parse/ParsePragma.cpp


Index: clang/lib/Parse/ParsePragma.cpp
===================================================================
--- clang/lib/Parse/ParsePragma.cpp
+++ clang/lib/Parse/ParsePragma.cpp
@@ -4040,8 +4040,6 @@
   }
 
   PP.Lex(Tok);
-  II = Tok.getIdentifierInfo();
-  StringRef IntrinsicClass = II->getName();
   if (!II || !(II->isStr("vector") || II->isStr("sifive_vector"))) {
     PP.Diag(Tok.getLocation(), diag::warn_pragma_invalid_argument)
         << PP.getSpelling(Tok) << "riscv" << /*Expected=*/true
@@ -4056,6 +4054,7 @@
     return;
   }
 
+  StringRef IntrinsicClass = II->getName();
   if (IntrinsicClass == "vector")
     Actions.DeclareRISCVVBuiltins = true;
   else if (IntrinsicClass == "sifive_vector")



Index: clang/lib/Parse/ParsePragma.cpp
===================================================================
--- clang/lib/Parse/ParsePragma.cpp
+++ clang/lib/Parse/ParsePragma.cpp
@@ -4040,8 +4040,6 @@
   }
 
   PP.Lex(Tok);
-  II = Tok.getIdentifierInfo();
-  StringRef IntrinsicClass = II->getName();
   if (!II || !(II->isStr("vector") || II->isStr("sifive_vector"))) {
     PP.Diag(Tok.getLocation(), diag::warn_pragma_invalid_argument)
         << PP.getSpelling(Tok) << "riscv" << /*Expected=*/true
@@ -4056,6 +4054,7 @@
     return;
   }
 
+  StringRef IntrinsicClass = II->getName();
   if (IntrinsicClass == "vector")
     Actions.DeclareRISCVVBuiltins = true;
   else if (IntrinsicClass == "sifive_vector")

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