Implemented tab usage only for indentation (http://llvm.org/PR17363)

Summary:
Changed UseTab to be a enum with three options: Never, Always,
ForIndentation (true/false are still supported when reading .clang-format).
IndentLevel should currently be propagated correctly for all tokens, except for
block comments. Please take a look at the general idea before I start dealing
with block comments.

Reviewers: klimek, djasper

Reviewed By: klimek

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1770

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191527 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index c5fa70c..4c73991 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -5758,7 +5758,7 @@
 TEST_F(FormatTest, ConfigurableUseOfTab) {
   FormatStyle Tab = getLLVMStyleWithColumns(42);
   Tab.IndentWidth = 8;
-  Tab.UseTab = true;
+  Tab.UseTab = FormatStyle::UT_Always;
   Tab.AlignEscapedNewlinesLeft = true;
 
   EXPECT_EQ("if (aaaaaaaa && // q\n"
@@ -5858,7 +5858,83 @@
                    " \t  */",
                    Tab));
 
-  Tab.UseTab = false;
+  Tab.UseTab = FormatStyle::UT_ForIndentation;
+  EXPECT_EQ("if (aaaaaaaa && // q\n"
+            "    bb)         // w\n"
+            "\t;",
+            format("if (aaaaaaaa &&// q\n"
+                   "bb)// w\n"
+                   ";",
+                   Tab));
+  verifyFormat("class X {\n"
+               "\tvoid f() {\n"
+               "\t\tsomeFunction(parameter1,\n"
+               "\t\t             parameter2);\n"
+               "\t}\n"
+               "};",
+               Tab);
+  verifyFormat("{\n"
+               "\tQ({\n"
+               "\t\t  int a;\n"
+               "\t\t  someFunction(aaaaaaaaaa,\n"
+               "\t\t               bbbbbbbbb);\n"
+               "\t  },\n"
+               "\t  p);\n"
+               "}",
+               Tab);
+  EXPECT_EQ("{\n"
+            "\t/* aaaa\n"
+            "\t   bbbb */\n"
+            "}",
+            format("{\n"
+                   "/* aaaa\n"
+                   "   bbbb */\n"
+                   "}",
+                   Tab));
+  EXPECT_EQ("{\n"
+            "\t/*\n"
+            "\t  aaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+            "\t  bbbbbbbbbbbbb\n"
+            "\t*/\n"
+            "}",
+            format("{\n"
+                   "/*\n"
+                   "  aaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbb\n"
+                   "*/\n"
+                   "}",
+                   Tab));
+  EXPECT_EQ("{\n"
+            "\t// aaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+            "\t// bbbbbbbbbbbbb\n"
+            "}",
+            format("{\n"
+                   "\t// aaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbb\n"
+                   "}",
+                   Tab));
+  EXPECT_EQ("{\n"
+            "\t/*\n"
+            "\t  aaaaaaaaaaaaaaaaaaaaaaaaaa\n"
+            "\t  bbbbbbbbbbbbb\n"
+            "\t*/\n"
+            "}",
+            format("{\n"
+                   "\t/*\n"
+                   "\t  aaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbb\n"
+                   "\t*/\n"
+                   "}",
+                   Tab));
+  EXPECT_EQ("{\n"
+            "\t/*\n"
+            "\n"
+            "\t*/\n"
+            "}",
+            format("{\n"
+                   "\t/*\n"
+                   "\n"
+                   "\t*/\n"
+                   "}", Tab));
+
+  Tab.UseTab = FormatStyle::UT_Never;
   EXPECT_EQ("/*\n"
             "              a\t\tcomment\n"
             "              in multiple lines\n"
@@ -6265,7 +6341,6 @@
   CHECK_PARSE_BOOL(ObjCSpaceBeforeProtocolList);
   CHECK_PARSE_BOOL(PointerBindsToType);
   CHECK_PARSE_BOOL(Cpp11BracedListStyle);
-  CHECK_PARSE_BOOL(UseTab);
   CHECK_PARSE_BOOL(IndentFunctionDeclarationAfterType);
   CHECK_PARSE_BOOL(SpacesInParentheses);
   CHECK_PARSE_BOOL(SpaceInEmptyParentheses);
@@ -6292,6 +6367,13 @@
   CHECK_PARSE("Standard: C++11", Standard, FormatStyle::LS_Cpp11);
   CHECK_PARSE("Standard: Auto", Standard, FormatStyle::LS_Auto);
 
+  Style.UseTab = FormatStyle::UT_ForIndentation;
+  CHECK_PARSE("UseTab: false", UseTab, FormatStyle::UT_Never);
+  CHECK_PARSE("UseTab: true", UseTab, FormatStyle::UT_Always);
+  CHECK_PARSE("UseTab: Never", UseTab, FormatStyle::UT_Never);
+  CHECK_PARSE("UseTab: ForIndentation", UseTab, FormatStyle::UT_ForIndentation);
+  CHECK_PARSE("UseTab: Always", UseTab, FormatStyle::UT_Always);
+
   Style.ColumnLimit = 123;
   FormatStyle BaseStyle = getLLVMStyle();
   CHECK_PARSE("BasedOnStyle: LLVM", ColumnLimit, BaseStyle.ColumnLimit);