Formatter: Get bit tests in ifs right.

It's generally not possible to know if 'a' '*' 'b' is a multiplication
expression or a variable declaration with a purely lexer-based approach. The
formatter currently uses a heuristic that classifies this token sequence as a
multiplication in rhs contexts (after '=' or 'return') and as a declaration
else.

Because of this, it gets bit tests in ifs, such as "if (a & b)" wrong. However,
declarations in ifs always have to be followed by '=', so this patch changes
the formatter to classify '&' as an operator if it's at the start of an if
statement.

Before:
  if (a& b)
  if (int* b = f())

Now:
  if (a & b)
  if (int* b = f())



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172731 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 0 deletions

diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 28d9fbe4e2..7b57e858a4 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -1235,6 +1235,14 @@ TEST_F(FormatTest, UnderstandsUsesOfStarAndAmp) {
       "  *A, // Operator detection might be confused by the '{'\n"
       "  *BB // Operator detection might be confused by previous comment\n"
       "};");
+
+  verifyFormat("if (int *a = &b)");
+  verifyFormat("if (int &a = *b)");
+  verifyFormat("if (a & b[i])");
+  verifyFormat("if (a::b::c::d & b[i])");
+  verifyFormat("if (*b[i])");
+  verifyFormat("if (int *a = (&b))");
+  verifyFormat("while (int *a = &b)");
 }
 
 TEST_F(FormatTest, FormatsCasts) {