[clang] 975467e - [Diagnostics] Handle string concat pattern and avoid false positives

[Arthur O'Dwyer via cfe-commits]

Hi Dávid,
Does this part of the patch imply that we *don't *want to warn on
    "foo" TWO
? and if so, why not?
Anyway, I think at least
    "foo" TWO
should be kept in the test suite, as a test-for-absence-of-warning.

                              TWO "bar",
-                             "foo" TWO // expected-note{{place parentheses
around the string literal to silence warning}}
+                             "foo" "bar" TWO // expected-note{{place
parentheses around the string literal to silence warning}}

my $.02,
Arthur

On Sun, Aug 9, 2020 at 10:03 AM Dávid Bolvanský via cfe-commits <
cfe-commits at lists.llvm.org> wrote:

>
> Author: Dávid Bolvanský
> Date: 2020-08-09T16:02:41+02:00
> New Revision: 975467e4aa7ce1b8fcf4af0e25cdf053cfa8669e
>
> URL:
> https://github.com/llvm/llvm-project/commit/975467e4aa7ce1b8fcf4af0e25cdf053cfa8669e
> DIFF:
> https://github.com/llvm/llvm-project/commit/975467e4aa7ce1b8fcf4af0e25cdf053cfa8669e.diff
>
> LOG: [Diagnostics] Handle string concat pattern and avoid false positives
>
> Added:
>
>
> Modified:
>     clang/lib/Sema/SemaExpr.cpp
>     clang/test/Sema/string-concat.c
>
> Removed:
>
>
>
>
> ################################################################################
> diff  --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
> index 35047a7b2b14..74427f8cd7ae 100644
> --- a/clang/lib/Sema/SemaExpr.cpp
> +++ b/clang/lib/Sema/SemaExpr.cpp
> @@ -6908,10 +6908,13 @@ Sema::ActOnInitList(SourceLocation LBraceLoc,
> MultiExprArg InitArgList,
>          << InitArgList[I]->getSourceRange();
>      } else if (const auto *SL = dyn_cast<StringLiteral>(InitArgList[I])) {
>        unsigned NumConcat = SL->getNumConcatenated();
> +      const auto *SLNext =
> +          dyn_cast<StringLiteral>(InitArgList[I + 1 < E ? I + 1 : 0]);
>        // Diagnose missing comma in string array initialization.
> -      // Do not warn when all the elements in the initializer are
> concatenated together.
> -      // Do not warn for macros too.
> -      if (NumConcat > 1 && E > 2 && !SL->getBeginLoc().isMacroID()) {
> +      // Do not warn when all the elements in the initializer are
> concatenated
> +      // together. Do not warn for macros too.
> +      if (NumConcat > 1 && E > 2 && !SL->getBeginLoc().isMacroID() &&
> SLNext &&
> +          NumConcat != SLNext->getNumConcatenated()) {
>          SmallVector<FixItHint, 1> Hints;
>          for (unsigned i = 0; i < NumConcat - 1; ++i)
>            Hints.push_back(FixItHint::CreateInsertion(
>
> diff  --git a/clang/test/Sema/string-concat.c
> b/clang/test/Sema/string-concat.c
> index c93bbd4eaa00..13e9656d2536 100644
> --- a/clang/test/Sema/string-concat.c
> +++ b/clang/test/Sema/string-concat.c
> @@ -61,7 +61,7 @@ char missing_comma_inner[][5] = {
>  #define TWO "foo"
>  const char *macro_test[] = { ONE("foo") "bar",
>                               TWO "bar",
> -                             "foo" TWO // expected-note{{place
> parentheses around the string literal to silence warning}}
> +                             "foo" "bar" TWO // expected-note{{place
> parentheses around the string literal to silence warning}}
>                             };          // expected-warning at -1{{suspicious
> concatenation of string literals in an array initialization; did you mean
> to separate the elements with a comma?}}
>
>  // Do not warn for macros.
> @@ -104,6 +104,12 @@ const char *not_warn[] = {
>      "world", "test"
>  };
>
> +const char *not_warn2[] = {
> +    "// Aaa\\\n"   " Bbb\\ \n"   " Ccc?" "?/\n",
> +    "// Aaa\\\r\n" " Bbb\\ \r\n" " Ccc?" "?/\r\n",
> +    "// Aaa\\\r"   " Bbb\\ \r"   " Ccc?" "?/\r"
> +  };
> +
>  // Do not warn when all the elements in the initializer are concatenated
> together.
>  const char *all_elems_in_init_concatenated[] = {"a" "b" "c"};
>
>
>
>
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