libclang: Add a function to libclang for retrieving the bit width value

Patch by Jyun-Yan You.

llvm-svn: 169276

clang/include/clang-c/Index.h

@@ -32,7 +32,7 @@
  * compatible, thus CINDEX_VERSION_MAJOR is expected to remain stable.
  */
 #define CINDEX_VERSION_MAJOR 0
-#define CINDEX_VERSION_MINOR 7
+#define CINDEX_VERSION_MINOR 8
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \
@@ -2682,6 +2682,13 @@ CINDEX_LINKAGE long long clang_getEnumConstantDeclValue(CXCursor C);
  */
 CINDEX_LINKAGE unsigned long long clang_getEnumConstantDeclUnsignedValue(CXCursor C);
 
+/**
+ * \brief Retrieve the bit width of a bit field declaration as an integer.
+ *
+ * If a cursor that is not a bit field declaration is passed in, -1 is returned.
+ */
+CINDEX_LINKAGE int clang_getFieldDeclBitWidth(CXCursor C);
+
 /**
  * \brief Retrieve the number of non-variadic arguments associated with a given
  * cursor.

clang/test/Index/print-bitwidth.c

@@ -0,0 +1,25 @@
+union S {
+  unsigned ac : 4;
+  unsigned : 4;
+  unsigned clock : 1;
+  unsigned : 0;
+  unsigned flag : 1;
+};
+
+struct X {
+  unsigned light : 1;
+  unsigned toaster : 1;
+  int count;
+  union S stat;
+};
+
+// RUN: c-index-test -test-print-bitwidth %s | FileCheck %s
+// CHECK: FieldDecl=ac:2:12 (Definition) bitwidth=4
+// CHECK: FieldDecl=:3:3 (Definition) bitwidth=4
+// CHECK: FieldDecl=clock:4:12 (Definition) bitwidth=1
+// CHECK: FieldDecl=:5:3 (Definition) bitwidth=0
+// CHECK: FieldDecl=flag:6:12 (Definition) bitwidth=1
+// CHECK: FieldDecl=light:10:12 (Definition) bitwidth=1
+// CHECK: FieldDecl=toaster:11:12 (Definition) bitwidth=1
+// CHECK-NOT: count
+// CHECK-NOT: stat

clang/tools/c-index-test/c-index-test.c

@@ -1134,6 +1134,23 @@ static enum CXChildVisitResult PrintTypeKind(CXCursor cursor, CXCursor p,
   return CXChildVisit_Recurse;
 }
 
+/******************************************************************************/
+/* Bitwidth testing.                                                          */
+/******************************************************************************/
+
+static enum CXChildVisitResult PrintBitWidth(CXCursor cursor, CXCursor p,
+                                             CXClientData d) {
+  if (clang_getCursorKind(cursor) != CXCursor_FieldDecl)
+    return CXChildVisit_Recurse;
+
+  int Bitwidth = clang_getFieldDeclBitWidth(cursor);
+  if (Bitwidth >= 0) {
+    PrintCursor(cursor, NULL);
+    printf(" bitwidth=%d\n", Bitwidth);
+  }
+
+  return CXChildVisit_Recurse;
+}
 
 /******************************************************************************/
 /* Loading ASTs/source.                                                       */
@@ -3382,6 +3399,7 @@ static void print_usage(void) {
   fprintf(stderr,
     "       c-index-test -test-print-linkage-source {<args>}*\n"
     "       c-index-test -test-print-typekind {<args>}*\n"
+    "       c-index-test -test-print-bitwidth {<args>}*\n"
     "       c-index-test -print-usr [<CursorKind> {<args>}]*\n"
     "       c-index-test -print-usr-file <file>\n"
     "       c-index-test -write-pch <file> <compiler arguments>\n");
@@ -3463,6 +3481,9 @@ int cindextest_main(int argc, const char **argv) {
   else if (argc > 2 && strcmp(argv[1], "-test-print-typekind") == 0)
     return perform_test_load_source(argc - 2, argv + 2, "all",
                                     PrintTypeKind, 0);
+  else if (argc > 2 && strcmp(argv[1], "-test-print-bitwidth") == 0)
+    return perform_test_load_source(argc - 2, argv + 2, "all",
+                                    PrintBitWidth, 0);
   else if (argc > 1 && strcmp(argv[1], "-print-usr") == 0) {
     if (argc > 2)
       return print_usrs(argv + 2, argv + argc);

clang/tools/libclang/CXType.cpp

@@ -265,6 +265,21 @@ unsigned long long clang_getEnumConstantDeclUnsignedValue(CXCursor C) {
   return ULLONG_MAX;
 }
 
+int clang_getFieldDeclBitWidth(CXCursor C) {
+  using namespace cxcursor;
+
+  if (clang_isDeclaration(C.kind)) {
+    Decl *D = getCursorDecl(C);
+
+    if (FieldDecl *FD = dyn_cast_or_null<FieldDecl>(D)) {
+      if (FD->isBitField())
+        return FD->getBitWidthValue(getCursorContext(C));
+    }
+  }
+
+  return -1;
+}
+
 CXType clang_getCanonicalType(CXType CT) {
   if (CT.kind == CXType_Invalid)
     return CT;

clang/tools/libclang/libclang.exports

@@ -160,6 +160,7 @@ clang_getElementType
 clang_getEnumConstantDeclUnsignedValue
 clang_getEnumConstantDeclValue
 clang_getEnumDeclIntegerType
+clang_getFieldDeclBitWidth
 clang_getExpansionLocation
 clang_getFile
 clang_getFileName