[autocompletion] Handle the space before pressing tab

Summary:
Distinguish "--autocomplete=-someflag" and "--autocomplete=-someflag,"
because the latter indicates that the user put a space before pushing tab
which should end up in a file completion.

Differential Revision: https://reviews.llvm.org/D53639

llvm-svn: 345133

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 583803de575..453758196cf 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1508,6 +1508,11 @@ void Driver::HandleAutocompletions(StringRef PassedFlags) const {
   unsigned short DisableFlags =
       options::NoDriverOption | options::Unsupported | options::Ignored;
 
+  // Distinguish "--autocomplete=-someflag" and "--autocomplete=-someflag,"
+  // because the latter indicates that the user put space before pushing tab
+  // which should end up in a file completion.
+  const bool HasSpace = PassedFlags.endswith(",");
+
   // Parse PassedFlags by "," as all the command-line flags are passed to this
   // function separated by ","
   StringRef TargetFlags = PassedFlags;
@@ -1534,6 +1539,16 @@ void Driver::HandleAutocompletions(StringRef PassedFlags) const {
   if (SuggestedCompletions.empty())
     SuggestedCompletions = Opts->suggestValueCompletions(Cur, "");
 
+  // If Flags were empty, it means the user typed `clang [tab]` where we should
+  // list all possible flags. If there was no value completion and the user
+  // pressed tab after a space, we should fall back to a file completion.
+  // We're printing a newline to be consistent with what we print at the end of
+  // this function.
+  if (SuggestedCompletions.empty() && HasSpace && !Flags.empty()) {
+    llvm::outs() << '\n';
+    return;
+  }
+
   // When flag ends with '=' and there was no value completion, return empty
   // string and fall back to the file autocompletion.
   if (SuggestedCompletions.empty() && !Cur.endswith("=")) {