[clang][lex][minimizer] Avoid treating path separators as comments

[jansvoboda11]

Summary

The minimizer strips out single-line comments (introduced by //). This sequence of characters can also appear in #include or #import directives where they play the role of path separators. We already avoid stripping this character sequence for #include but not for #import (which has the same semantics). This patch makes it so #import <A//A.h> is not affected by minimization. Previously, we would incorrectly reduce it into #import <A.

[arphaman]

Cheers, LGTM

clang/lib/Lex/DependencyDirectivesSourceMinimizer.cpp

 }
 
 void Minimizer::printToNewline(const char *&First, const char *const End) {
   while (First != End && !isVerticalWhitespace(*First)) {
     const char *Last = First;
     do {
       // Iterate over strings correctly to avoid comments and newlines.
       if (*Last == '"' || *Last == '\'' ||
-          (*Last == '<' && top() == pp_include)) {
+          (*Last == '<' && (top() == pp_include || top() == pp_import))) {
         if (LLVM_UNLIKELY(isRawStringLiteral(First, Last)))
           skipRawString(Last, End);
         else
           skipString(Last, End);
         continue;
       }
       if (*Last != '/' || End - Last < 2) {
         ++Last;

clang/unittests/Lex/DependencyDirectivesSourceMinimizerTest.cpp

TEST(MinimizeSourceToDependencyDirectivesTest, Include) {
 
   ASSERT_FALSE(minimizeSourceToDependencyDirectives("#include \"A\"\n", Out));
   EXPECT_STREQ("#include \"A\"\n", Out.data());
 
   ASSERT_FALSE(minimizeSourceToDependencyDirectives("#include <A>\n", Out));
   EXPECT_STREQ("#include <A>\n", Out.data());
 
   ASSERT_FALSE(
+      minimizeSourceToDependencyDirectives("#include <A//A.h>\n", Out));
+  EXPECT_STREQ("#include <A//A.h>\n", Out.data());
+
+  ASSERT_FALSE(
+      minimizeSourceToDependencyDirectives("#include \"A//A.h\"\n", Out));
+  EXPECT_STREQ("#include \"A//A.h\"\n", Out.data());
+
+  ASSERT_FALSE(
       minimizeSourceToDependencyDirectives("#include_next <A>\n", Out));
   EXPECT_STREQ("#include_next <A>\n", Out.data());
 
   ASSERT_FALSE(minimizeSourceToDependencyDirectives("#import <A>\n", Out));
   EXPECT_STREQ("#import <A>\n", Out.data());
 
+  ASSERT_FALSE(minimizeSourceToDependencyDirectives("#import <A//A.h>\n", Out));
+  EXPECT_STREQ("#import <A//A.h>\n", Out.data());
+
+  ASSERT_FALSE(
+      minimizeSourceToDependencyDirectives("#import \"A//A.h\"\n", Out));
+  EXPECT_STREQ("#import \"A//A.h\"\n", Out.data());
+
   ASSERT_FALSE(
       minimizeSourceToDependencyDirectives("#__include_macros <A>\n", Out));
   EXPECT_STREQ("#__include_macros <A>\n", Out.data());
 }
 
 TEST(MinimizeSourceToDependencyDirectivesTest, AtImport) {
   SmallVector<char, 128> Out;