[CommandLineParser] Add DefaultOption flag

Summary: Add DefaultOption flag to CommandLineParser which provides a
default option or alias, but allows users to override it for some
other purpose as needed.

Also, add `-h` as a default alias to `-help`, which can be seamlessly
overridden by applications like llvm-objdump and llvm-readobj which
use `-h` as an alias for other options.

(relanding after revert, r358414)
Added DefaultOptions.clear() to reset().

Reviewers: alexfh, klimek

Reviewed By: klimek

Subscribers: kristina, MaskRay, mehdi_amini, inglorion, dexonsmith, hiraditya, llvm-commits, jhenderson, arphaman, cfe-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D59746

llvm-svn: 358428

1 files changed, 62 insertions, 0 deletions

diff --git a/llvm/unittests/Support/CommandLineTest.cpp b/llvm/unittests/Support/CommandLineTest.cpp
index a7aee41..fcbfd33 100644
--- a/llvm/unittests/Support/CommandLineTest.cpp
+++ b/llvm/unittests/Support/CommandLineTest.cpp
@@ -620,6 +620,68 @@ TEST(CommandLineTest, GetRegisteredSubcommands) {
   }
 }
 
+TEST(CommandLineTest, DefaultOptions) {
+  cl::ResetCommandLineParser();
+
+  StackOption<std::string> Bar("bar", cl::sub(*cl::AllSubCommands),
+                               cl::DefaultOption);
+  StackOption<std::string, cl::alias> Bar_Alias(
+      "b", cl::desc("Alias for -bar"), cl::aliasopt(Bar), cl::DefaultOption);
+
+  StackOption<bool> Foo("foo", cl::init(false), cl::sub(*cl::AllSubCommands),
+                        cl::DefaultOption);
+  StackOption<bool, cl::alias> Foo_Alias("f", cl::desc("Alias for -foo"),
+                                         cl::aliasopt(Foo), cl::DefaultOption);
+
+  StackSubCommand SC1("sc1", "First Subcommand");
+  // Override "-b" and change type in sc1 SubCommand.
+  StackOption<bool> SC1_B("b", cl::sub(SC1), cl::init(false));
+  StackSubCommand SC2("sc2", "Second subcommand");
+  // Override "-foo" and change type in sc2 SubCommand.  Note that this does not
+  // affect "-f" alias, which continues to work correctly.
+  StackOption<std::string> SC2_Foo("foo", cl::sub(SC2));
+
+  const char *args0[] = {"prog", "-b", "args0 bar string", "-f"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(sizeof(args0) / sizeof(char *), args0,
+                                          StringRef(), &llvm::nulls()));
+  EXPECT_TRUE(Bar == "args0 bar string");
+  EXPECT_TRUE(Foo);
+  EXPECT_FALSE(SC1_B);
+  EXPECT_TRUE(SC2_Foo.empty());
+
+  cl::ResetAllOptionOccurrences();
+
+  const char *args1[] = {"prog", "sc1", "-b", "-bar", "args1 bar string", "-f"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(sizeof(args1) / sizeof(char *), args1,
+                                          StringRef(), &llvm::nulls()));
+  EXPECT_TRUE(Bar == "args1 bar string");
+  EXPECT_TRUE(Foo);
+  EXPECT_TRUE(SC1_B);
+  EXPECT_TRUE(SC2_Foo.empty());
+  for (auto *S : cl::getRegisteredSubcommands()) {
+    if (*S) {
+      EXPECT_EQ("sc1", S->getName());
+    }
+  }
+
+  cl::ResetAllOptionOccurrences();
+
+  const char *args2[] = {"prog", "sc2", "-b", "args2 bar string",
+                         "-f", "-foo", "foo string"};
+  EXPECT_TRUE(cl::ParseCommandLineOptions(sizeof(args2) / sizeof(char *), args2,
+                                          StringRef(), &llvm::nulls()));
+  EXPECT_TRUE(Bar == "args2 bar string");
+  EXPECT_TRUE(Foo);
+  EXPECT_FALSE(SC1_B);
+  EXPECT_TRUE(SC2_Foo == "foo string");
+  for (auto *S : cl::getRegisteredSubcommands()) {
+    if (*S) {
+      EXPECT_EQ("sc2", S->getName());
+    }
+  }
+  cl::ResetCommandLineParser();
+}
+
 TEST(CommandLineTest, ArgumentLimit) {
   std::string args(32 * 4096, 'a');
   EXPECT_FALSE(llvm::sys::commandLineFitsWithinSystemLimits("cl", args.data()));