[clang] Fix static analyzer concerns in #embed code (#99331)

Summary:
1. Dead code in `LookupEmbedFile`. The loop always exited on the first
iteration. This was also causing a bug of not checking all directories
provided by `--embed-dir`.

2. Use of uninitialized variable `CurTok` in `LexEmbedParameters`. It
was used to initialize the field which seems to be unused. Removed
unused field, this way `CurTok` should be initialized by Lex method.

Test Plan: 

Reviewers: 

Subscribers: 

Tasks: 

Tags: 


Differential Revision: https://phabricator.intern.facebook.com/D60251687

Author: Fznamznon

clang/include/clang/Lex/PPEmbedParameters.h

@@ -75,7 +75,6 @@ struct LexEmbedParametersResult {
   std::optional<PPEmbedParameterIfEmpty> MaybeIfEmptyParam;
   std::optional<PPEmbedParameterPrefix> MaybePrefixParam;
   std::optional<PPEmbedParameterSuffix> MaybeSuffixParam;
-  SourceRange ParamRange;
   int UnrecognizedParams;
 
   size_t PrefixTokenCount() const {

clang/lib/Lex/PPDirectives.cpp

@@ -1137,7 +1137,9 @@ Preprocessor::LookupEmbedFile(StringRef Filename, bool isAngled, bool OpenFile,
     SeparateComponents(LookupPath, Entry, Filename, false);
     llvm::Expected<FileEntryRef> ShouldBeEntry =
         FM.getFileRef(LookupPath, OpenFile);
-    return llvm::expectedToOptional(std::move(ShouldBeEntry));
+    if (ShouldBeEntry)
+      return llvm::expectedToOptional(std::move(ShouldBeEntry));
+    llvm::consumeError(ShouldBeEntry.takeError());
   }
   return std::nullopt;
 }
@@ -3624,12 +3626,10 @@ Preprocessor::LexEmbedParameters(Token &CurTok, bool ForHasEmbed) {
   LexEmbedParametersResult Result{};
   SmallVector<Token, 2> ParameterTokens;
   tok::TokenKind EndTokenKind = ForHasEmbed ? tok::r_paren : tok::eod;
-  Result.ParamRange = {CurTok.getLocation(), CurTok.getLocation()};
 
   auto DiagMismatchedBracesAndSkipToEOD =
       [&](tok::TokenKind Expected,
           std::pair<tok::TokenKind, SourceLocation> Matches) {
-        Result.ParamRange.setEnd(CurTok.getEndLoc());
         Diag(CurTok, diag::err_expected) << Expected;
         Diag(Matches.second, diag::note_matching) << Matches.first;
         if (CurTok.isNot(tok::eod))
@@ -3638,7 +3638,6 @@ Preprocessor::LexEmbedParameters(Token &CurTok, bool ForHasEmbed) {
 
   auto ExpectOrDiagAndSkipToEOD = [&](tok::TokenKind Kind) {
     if (CurTok.isNot(Kind)) {
-      Result.ParamRange.setEnd(CurTok.getEndLoc());
       Diag(CurTok, diag::err_expected) << Kind;
       if (CurTok.isNot(tok::eod))
         DiscardUntilEndOfDirective(CurTok);
@@ -3872,7 +3871,6 @@ Preprocessor::LexEmbedParameters(Token &CurTok, bool ForHasEmbed) {
       }
     }
   }
-  Result.ParamRange.setEnd(CurTok.getLocation());
   return Result;
 }
 

clang/test/Preprocessor/embed_search_paths.c

@@ -0,0 +1,4 @@
+// RUN: %clang_cc1 -std=c23 %s -E -verify --embed-dir=%S --embed-dir=%S/Inputs
+// expected-no-diagnostics
+
+#embed <jk.txt>