[backported/clang-7][libclang] Add PrintingPolicy for pretty printing declarations

-------------------------------------------------------------------------
* Improves pretty printing for Qt Creator's tooltips.
-------------------------------------------------------------------------

Summary:
Introduce clang_getCursorPrettyPrinted() for pretty printing
declarations. Expose also PrintingPolicy, so the user gets more
fine-grained control of the entities being printed.

The already existing clang_getCursorDisplayName() is pretty limited -
for example, it does not handle return types, parameter names or default
arguments for function declarations. Addressing these issues in
clang_getCursorDisplayName() would mean to duplicate existing code
(e.g. clang::DeclPrinter), so rather expose new API to access the
existing functionality.

Reviewed By: jbcoe

Subscribers: cfe-commits

Tags: #clang

Patch by nik (Nikolai Kosjar)

Differential Revision: https://reviews.llvm.org/D39903

Change-Id: I509a01bb5a1e4e1d899c2725f50ed78e482c075f
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

6 files changed, 428 insertions, 12 deletions

diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index ee522f43f7..0179058944 100644
--- a/include/clang-c/Index.h
+++ b/include/clang-c/Index.h
@@ -34,6 +34,7 @@
 #define CINDEX_VERSION_MAJOR 0
 #define CINDEX_VERSION_MINOR 45
 #define CINDEX_VERSION_HAS_ISINVALIDECL_BACKPORTED
+#define CINDEX_VERSION_HAS_PRETTYDECL_BACKPORTED
 
 #define CINDEX_VERSION_ENCODE(major, minor) ( \
       ((major) * 10000)                       \
@@ -4093,6 +4094,90 @@ CINDEX_LINKAGE CXSourceRange clang_Cursor_getSpellingNameRange(CXCursor,
                                                           unsigned options);
 
 /**
+ * \brief Opaque pointer representing a policy that controls pretty printing
+ * for \c clang_getCursorPrettyPrinted.
+ */
+typedef void *CXPrintingPolicy;
+
+/**
+ * \brief Properties for the printing policy.
+ *
+ * See \c clang::PrintingPolicy for more information.
+ */
+enum CXPrintingPolicyProperty {
+  CXPrintingPolicy_Indentation,
+  CXPrintingPolicy_SuppressSpecifiers,
+  CXPrintingPolicy_SuppressTagKeyword,
+  CXPrintingPolicy_IncludeTagDefinition,
+  CXPrintingPolicy_SuppressScope,
+  CXPrintingPolicy_SuppressUnwrittenScope,
+  CXPrintingPolicy_SuppressInitializers,
+  CXPrintingPolicy_ConstantArraySizeAsWritten,
+  CXPrintingPolicy_AnonymousTagLocations,
+  CXPrintingPolicy_SuppressStrongLifetime,
+  CXPrintingPolicy_SuppressLifetimeQualifiers,
+  CXPrintingPolicy_SuppressTemplateArgsInCXXConstructors,
+  CXPrintingPolicy_Bool,
+  CXPrintingPolicy_Restrict,
+  CXPrintingPolicy_Alignof,
+  CXPrintingPolicy_UnderscoreAlignof,
+  CXPrintingPolicy_UseVoidForZeroParams,
+  CXPrintingPolicy_TerseOutput,
+  CXPrintingPolicy_PolishForDeclaration,
+  CXPrintingPolicy_Half,
+  CXPrintingPolicy_MSWChar,
+  CXPrintingPolicy_IncludeNewlines,
+  CXPrintingPolicy_MSVCFormatting,
+  CXPrintingPolicy_ConstantsAsWritten,   /* Ops, not yet there in clang 5.0 and we do not need it. */
+  CXPrintingPolicy_SuppressImplicitBase, /* Ops, not yet there in clang 5.0 and we do not need it. */
+  CXPrintingPolicy_FullyQualifiedName,
+
+  CXPrintingPolicy_LastProperty = CXPrintingPolicy_FullyQualifiedName
+};
+
+/**
+ * \brief Get a property value for the given printing policy.
+ */
+CINDEX_LINKAGE unsigned
+clang_PrintingPolicy_getProperty(CXPrintingPolicy Policy,
+                                 enum CXPrintingPolicyProperty Property);
+
+/**
+ * \brief Set a property value for the given printing policy.
+ */
+CINDEX_LINKAGE void
+clang_PrintingPolicy_setProperty(CXPrintingPolicy Policy,
+                                 enum CXPrintingPolicyProperty Property,
+                                 unsigned Value);
+
+/**
+ * \brief Retrieve the default policy for the cursor.
+ *
+ * The policy should be released after use with \c
+ * clang_PrintingPolicy_dispose.
+ */
+CINDEX_LINKAGE CXPrintingPolicy clang_getCursorPrintingPolicy(CXCursor);
+
+/**
+ * \brief Release a printing policy.
+ */
+CINDEX_LINKAGE void clang_PrintingPolicy_dispose(CXPrintingPolicy Policy);
+
+/**
+ * \brief Pretty print declarations.
+ *
+ * \param Cursor The cursor representing a declaration.
+ *
+ * \param Policy The policy to control the entities being printed. If
+ * NULL, a default policy is used.
+ *
+ * \returns The pretty printed declaration or the empty string for
+ * other cursors.
+ */
+CINDEX_LINKAGE CXString clang_getCursorPrettyPrinted(CXCursor Cursor,
+                                                     CXPrintingPolicy Policy);
+
+/**
  * \brief Retrieve the display name for the entity referenced by this cursor.
  *
  * The display name contains extra information that helps identify the cursor,
diff --git a/test/Index/print-display-names.cpp b/test/Index/print-display-names.cpp
index 94fe4665e6..5ba10e43bc 100644
--- a/test/Index/print-display-names.cpp
+++ b/test/Index/print-display-names.cpp
@@ -12,9 +12,20 @@ void g(ClassTmpl<T, T>);
 
 template<> void g<int>(ClassTmpl<int, int>);
 
-// RUN: c-index-test -test-load-source all-display %s | FileCheck %s
-// CHECK: print-display-names.cpp:2:7: ClassTemplate=ClassTmpl<T, typename>:2:7
-// CHECK: print-display-names.cpp:6:16: ClassDecl=ClassTmpl<Integer, Integer>:6:16 (Definition)
-// CHECK: print-display-names.cpp:8:6: FunctionDecl=f(ClassTmpl<float, Integer>):8:6
-// CHECK: print-display-names.cpp:11:6: FunctionTemplate=g(ClassTmpl<T, T>):11:6
-// CHECK: print-display-names.cpp:13:17: FunctionDecl=g<>(ClassTmpl<int, int>):13:17 [Specialization of g:11:6]
+// RUN: c-index-test -test-load-source all-display %s | FileCheck %s --check-prefix=DISPLAY_NAME
+// DISPLAY_NAME: print-display-names.cpp:2:7: ClassTemplate=ClassTmpl<T, typename>:2:7
+// DISPLAY_NAME: print-display-names.cpp:6:16: ClassDecl=ClassTmpl<Integer, Integer>:6:16 (Definition)
+// DISPLAY_NAME: print-display-names.cpp:8:6: FunctionDecl=f(ClassTmpl<float, Integer>):8:6
+// DISPLAY_NAME: print-display-names.cpp:11:6: FunctionTemplate=g(ClassTmpl<T, T>):11:6
+// DISPLAY_NAME: print-display-names.cpp:13:17: FunctionDecl=g<>(ClassTmpl<int, int>):13:17 [Specialization of g:11:6]
+
+// RUN: env CINDEXTEST_PRINTINGPOLICY_TERSEOUTPUT=1 c-index-test -test-load-source all-pretty %s | FileCheck %s --check-prefix=PRETTY
+// PRETTY: print-display-names.cpp:2:7: ClassTemplate=template <typename T, typename > class ClassTmpl {}:2:7 (Definition) Extent=[1:1 - 2:20]
+// PRETTY: print-display-names.cpp:4:13: TypedefDecl=typedef int Integer:4:13 (Definition) Extent=[4:1 - 4:20]
+// PRETTY: print-display-names.cpp:6:16: ClassDecl=template<> class ClassTmpl<int, int> {}:6:16 (Definition) [Specialization of ClassTmpl:2:7] Extent=[6:1 - 6:43]
+// PRETTY: print-display-names.cpp:8:6: FunctionDecl=void f(ClassTmpl<float, Integer> p):8:6 Extent=[8:1 - 8:36]
+// PRETTY: print-display-names.cpp:8:34: ParmDecl=ClassTmpl<float, Integer> p:8:34 (Definition) Extent=[8:8 - 8:35]
+// PRETTY: print-display-names.cpp:11:6: FunctionTemplate=template <typename T> void g(ClassTmpl<T, T>):11:6 Extent=[10:1 - 11:24]
+// PRETTY: print-display-names.cpp:11:23: ParmDecl=ClassTmpl<T, T>:11:23 (Definition) Extent=[11:8 - 11:23]
+// PRETTY: print-display-names.cpp:13:17: FunctionDecl=template<> void g<int>(ClassTmpl<int, int>):13:17 [Specialization of g:11:6] [Template arg 0: kind: 1, type: int] Extent=[13:1 - 13:44]
+// PRETTY: print-display-names.cpp:13:43: ParmDecl=ClassTmpl<int, int>:13:43 (Definition) Extent=[13:24 - 13:43]
diff --git a/tools/c-index-test/c-index-test.c b/tools/c-index-test/c-index-test.c
index c5e345ef6a..e9902efffb 100644
--- a/tools/c-index-test/c-index-test.c
+++ b/tools/c-index-test/c-index-test.c
@@ -86,6 +86,69 @@ static unsigned getDefaultParsingOptions() {
   return options;
 }
 
+static void ModifyPrintingPolicyAccordingToEnv(CXPrintingPolicy Policy) {
+  struct Mapping {
+    const char *name;
+    enum CXPrintingPolicyProperty property;
+  };
+  struct Mapping mappings[] = {
+      {"CINDEXTEST_PRINTINGPOLICY_INDENTATION", CXPrintingPolicy_Indentation},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSSPECIFIERS",
+       CXPrintingPolicy_SuppressSpecifiers},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSTAGKEYWORD",
+       CXPrintingPolicy_SuppressTagKeyword},
+      {"CINDEXTEST_PRINTINGPOLICY_INCLUDETAGDEFINITION",
+       CXPrintingPolicy_IncludeTagDefinition},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSSCOPE",
+       CXPrintingPolicy_SuppressScope},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSUNWRITTENSCOPE",
+       CXPrintingPolicy_SuppressUnwrittenScope},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSINITIALIZERS",
+       CXPrintingPolicy_SuppressInitializers},
+      {"CINDEXTEST_PRINTINGPOLICY_CONSTANTARRAYSIZEASWRITTEN",
+       CXPrintingPolicy_ConstantArraySizeAsWritten},
+      {"CINDEXTEST_PRINTINGPOLICY_ANONYMOUSTAGLOCATIONS",
+       CXPrintingPolicy_AnonymousTagLocations},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSSTRONGLIFETIME",
+       CXPrintingPolicy_SuppressStrongLifetime},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSLIFETIMEQUALIFIERS",
+       CXPrintingPolicy_SuppressLifetimeQualifiers},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSTEMPLATEARGSINCXXCONSTRUCTORS",
+       CXPrintingPolicy_SuppressTemplateArgsInCXXConstructors},
+      {"CINDEXTEST_PRINTINGPOLICY_BOOL", CXPrintingPolicy_Bool},
+      {"CINDEXTEST_PRINTINGPOLICY_RESTRICT", CXPrintingPolicy_Restrict},
+      {"CINDEXTEST_PRINTINGPOLICY_ALIGNOF", CXPrintingPolicy_Alignof},
+      {"CINDEXTEST_PRINTINGPOLICY_UNDERSCOREALIGNOF",
+       CXPrintingPolicy_UnderscoreAlignof},
+      {"CINDEXTEST_PRINTINGPOLICY_USEVOIDFORZEROPARAMS",
+       CXPrintingPolicy_UseVoidForZeroParams},
+      {"CINDEXTEST_PRINTINGPOLICY_TERSEOUTPUT", CXPrintingPolicy_TerseOutput},
+      {"CINDEXTEST_PRINTINGPOLICY_POLISHFORDECLARATION",
+       CXPrintingPolicy_PolishForDeclaration},
+      {"CINDEXTEST_PRINTINGPOLICY_HALF", CXPrintingPolicy_Half},
+      {"CINDEXTEST_PRINTINGPOLICY_MSWCHAR", CXPrintingPolicy_MSWChar},
+      {"CINDEXTEST_PRINTINGPOLICY_INCLUDENEWLINES",
+       CXPrintingPolicy_IncludeNewlines},
+      {"CINDEXTEST_PRINTINGPOLICY_MSVCFORMATTING",
+       CXPrintingPolicy_MSVCFormatting},
+      {"CINDEXTEST_PRINTINGPOLICY_CONSTANTSASWRITTEN",
+       CXPrintingPolicy_ConstantsAsWritten},
+      {"CINDEXTEST_PRINTINGPOLICY_SUPPRESSIMPLICITBASE",
+       CXPrintingPolicy_SuppressImplicitBase},
+      {"CINDEXTEST_PRINTINGPOLICY_FULLYQUALIFIEDNAME",
+       CXPrintingPolicy_FullyQualifiedName},
+  };
+
+  unsigned i;
+  for (i = 0; i < sizeof(mappings) / sizeof(struct Mapping); i++) {
+    char *value = getenv(mappings[i].name);
+    if (value) {
+      clang_PrintingPolicy_setProperty(Policy, mappings[i].property,
+                                       (unsigned)strtoul(value, 0L, 10));
+    }
+  }
+}
+
 /** \brief Returns 0 in case of success, non-zero in case of a failure. */
 static int checkForErrors(CXTranslationUnit TU);
 
@@ -356,7 +419,11 @@ static void PrintRange(CXSourceRange R, const char *str) {
   PrintExtent(stdout, begin_line, begin_column, end_line, end_column);
 }
 
-int want_display_name = 0;
+static enum DisplayType {
+    DisplayType_Spelling,
+    DisplayType_DisplayName,
+    DisplayType_Pretty
+} wanted_display_type = DisplayType_Spelling;
 
 static void printVersion(const char *Prefix, CXVersion Version) {
   if (Version.Major < 0)
@@ -656,6 +723,24 @@ static int lineCol_cmp(const void *p1, const void *p2) {
   return (int)lhs->col - (int)rhs->col;
 }
 
+static CXString CursorToText(CXCursor Cursor) {
+  switch (wanted_display_type) {
+  case DisplayType_Spelling:
+    return clang_getCursorSpelling(Cursor);
+  case DisplayType_DisplayName:
+    return clang_getCursorDisplayName(Cursor);
+  case DisplayType_Pretty:
+  default: {
+    CXString text;
+    CXPrintingPolicy Policy = clang_getCursorPrintingPolicy(Cursor);
+    ModifyPrintingPolicyAccordingToEnv(Policy);
+    text = clang_getCursorPrettyPrinted(Cursor, Policy);
+    clang_PrintingPolicy_dispose(Policy);
+    return text;
+  }
+  }
+}
+
 static void PrintCursor(CXCursor Cursor, const char *CommentSchemaFile) {
   CXTranslationUnit TU = clang_Cursor_getTranslationUnit(Cursor);
   if (clang_isInvalid(Cursor.kind)) {
@@ -682,8 +767,7 @@ static void PrintCursor(CXCursor Cursor, const char *CommentSchemaFile) {
     int I;
 
     ks = clang_getCursorKindSpelling(Cursor.kind);
-    string = want_display_name? clang_getCursorDisplayName(Cursor) 
-                              : clang_getCursorSpelling(Cursor);
+    string = CursorToText(Cursor);
     printf("%s=%s", clang_getCString(ks),
                     clang_getCString(string));
     clang_disposeString(ks);
@@ -1686,7 +1770,12 @@ static int perform_test_load(CXIndex Idx, CXTranslationUnit TU,
     else if (!strcmp(filter, "all-display") || 
              !strcmp(filter, "local-display")) {
       ck = NULL;
-      want_display_name = 1;
+      wanted_display_type = DisplayType_DisplayName;
+    }
+    else if (!strcmp(filter, "all-pretty") ||
+             !strcmp(filter, "local-pretty")) {
+      ck = NULL;
+      wanted_display_type = DisplayType_Pretty;
     }
     else if (!strcmp(filter, "none")) K = (enum CXCursorKind) ~0;
     else if (!strcmp(filter, "category")) K = CXCursor_ObjCCategoryDecl;
@@ -1754,8 +1843,11 @@ int perform_test_load_source(int argc, const char **argv,
   const char *InvocationPath;
 
   Idx = clang_createIndex(/* excludeDeclsFromPCH */
-                          (!strcmp(filter, "local") || 
-                           !strcmp(filter, "local-display"))? 1 : 0,
+                          (!strcmp(filter, "local") ||
+                           !strcmp(filter, "local-display") ||
+                           !strcmp(filter, "local-pretty"))
+                              ? 1
+                              : 0,
                           /* displayDiagnostics=*/1);
   InvocationPath = getenv("CINDEXTEST_INVOCATION_EMISSION_PATH");
   if (InvocationPath)
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 429fca3474..bd2e4bc8d2 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -4706,6 +4706,197 @@ CXStringSet *clang_Cursor_getObjCManglings(CXCursor C) {
   return cxstring::createSet(Manglings);
 }
 
+CXPrintingPolicy clang_getCursorPrintingPolicy(CXCursor C) {
+  if (clang_Cursor_isNull(C))
+    return 0;
+  return new PrintingPolicy(getCursorContext(C).getPrintingPolicy());
+}
+
+void clang_PrintingPolicy_dispose(CXPrintingPolicy Policy) {
+  if (Policy)
+    delete static_cast<PrintingPolicy *>(Policy);
+}
+
+unsigned
+clang_PrintingPolicy_getProperty(CXPrintingPolicy Policy,
+                                 enum CXPrintingPolicyProperty Property) {
+  if (!Policy)
+    return 0;
+
+  PrintingPolicy *P = static_cast<PrintingPolicy *>(Policy);
+  switch (Property) {
+  case CXPrintingPolicy_Indentation:
+    return P->Indentation;
+  case CXPrintingPolicy_SuppressSpecifiers:
+    return P->SuppressSpecifiers;
+  case CXPrintingPolicy_SuppressTagKeyword:
+    return P->SuppressTagKeyword;
+  case CXPrintingPolicy_IncludeTagDefinition:
+    return P->IncludeTagDefinition;
+  case CXPrintingPolicy_SuppressScope:
+    return P->SuppressScope;
+  case CXPrintingPolicy_SuppressUnwrittenScope:
+    return P->SuppressUnwrittenScope;
+  case CXPrintingPolicy_SuppressInitializers:
+    return P->SuppressInitializers;
+  case CXPrintingPolicy_ConstantArraySizeAsWritten:
+    return P->ConstantArraySizeAsWritten;
+  case CXPrintingPolicy_AnonymousTagLocations:
+    return P->AnonymousTagLocations;
+  case CXPrintingPolicy_SuppressStrongLifetime:
+    return P->SuppressStrongLifetime;
+  case CXPrintingPolicy_SuppressLifetimeQualifiers:
+    return P->SuppressLifetimeQualifiers;
+  case CXPrintingPolicy_SuppressTemplateArgsInCXXConstructors:
+    return P->SuppressTemplateArgsInCXXConstructors;
+  case CXPrintingPolicy_Bool:
+    return P->Bool;
+  case CXPrintingPolicy_Restrict:
+    return P->Restrict;
+  case CXPrintingPolicy_Alignof:
+    return P->Alignof;
+  case CXPrintingPolicy_UnderscoreAlignof:
+    return P->UnderscoreAlignof;
+  case CXPrintingPolicy_UseVoidForZeroParams:
+    return P->UseVoidForZeroParams;
+  case CXPrintingPolicy_TerseOutput:
+    return P->TerseOutput;
+  case CXPrintingPolicy_PolishForDeclaration:
+    return P->PolishForDeclaration;
+  case CXPrintingPolicy_Half:
+    return P->Half;
+  case CXPrintingPolicy_MSWChar:
+    return P->MSWChar;
+  case CXPrintingPolicy_IncludeNewlines:
+    return P->IncludeNewlines;
+  case CXPrintingPolicy_MSVCFormatting:
+    return P->MSVCFormatting;
+  case CXPrintingPolicy_ConstantsAsWritten:
+    // Ops, not yet there in clang 5.0 and we do not need it.
+    return 0;
+  case CXPrintingPolicy_SuppressImplicitBase:
+    // Ops, not yet there in clang 5.0 and we do not need it.
+    return 0;
+  case CXPrintingPolicy_FullyQualifiedName:
+    return P->FullyQualifiedName;
+  }
+
+  assert(false && "Invalid CXPrintingPolicyProperty");
+  return 0;
+}
+
+void clang_PrintingPolicy_setProperty(CXPrintingPolicy Policy,
+                                      enum CXPrintingPolicyProperty Property,
+                                      unsigned Value) {
+  if (!Policy)
+    return;
+
+  PrintingPolicy *P = static_cast<PrintingPolicy *>(Policy);
+  switch (Property) {
+  case CXPrintingPolicy_Indentation:
+    P->Indentation = Value;
+    return;
+  case CXPrintingPolicy_SuppressSpecifiers:
+    P->SuppressSpecifiers = Value;
+    return;
+  case CXPrintingPolicy_SuppressTagKeyword:
+    P->SuppressTagKeyword = Value;
+    return;
+  case CXPrintingPolicy_IncludeTagDefinition:
+    P->IncludeTagDefinition = Value;
+    return;
+  case CXPrintingPolicy_SuppressScope:
+    P->SuppressScope = Value;
+    return;
+  case CXPrintingPolicy_SuppressUnwrittenScope:
+    P->SuppressUnwrittenScope = Value;
+    return;
+  case CXPrintingPolicy_SuppressInitializers:
+    P->SuppressInitializers = Value;
+    return;
+  case CXPrintingPolicy_ConstantArraySizeAsWritten:
+    P->ConstantArraySizeAsWritten = Value;
+    return;
+  case CXPrintingPolicy_AnonymousTagLocations:
+    P->AnonymousTagLocations = Value;
+    return;
+  case CXPrintingPolicy_SuppressStrongLifetime:
+    P->SuppressStrongLifetime = Value;
+    return;
+  case CXPrintingPolicy_SuppressLifetimeQualifiers:
+    P->SuppressLifetimeQualifiers = Value;
+    return;
+  case CXPrintingPolicy_SuppressTemplateArgsInCXXConstructors:
+    P->SuppressTemplateArgsInCXXConstructors = Value;
+    return;
+  case CXPrintingPolicy_Bool:
+    P->Bool = Value;
+    return;
+  case CXPrintingPolicy_Restrict:
+    P->Restrict = Value;
+    return;
+  case CXPrintingPolicy_Alignof:
+    P->Alignof = Value;
+    return;
+  case CXPrintingPolicy_UnderscoreAlignof:
+    P->UnderscoreAlignof = Value;
+    return;
+  case CXPrintingPolicy_UseVoidForZeroParams:
+    P->UseVoidForZeroParams = Value;
+    return;
+  case CXPrintingPolicy_TerseOutput:
+    P->TerseOutput = Value;
+    return;
+  case CXPrintingPolicy_PolishForDeclaration:
+    P->PolishForDeclaration = Value;
+    return;
+  case CXPrintingPolicy_Half:
+    P->Half = Value;
+    return;
+  case CXPrintingPolicy_MSWChar:
+    P->MSWChar = Value;
+    return;
+  case CXPrintingPolicy_IncludeNewlines:
+    P->IncludeNewlines = Value;
+    return;
+  case CXPrintingPolicy_MSVCFormatting:
+    P->MSVCFormatting = Value;
+    return;
+  case CXPrintingPolicy_ConstantsAsWritten:
+    // Ops, not yet there in clang 5.0 and we do not need it.
+    return;
+  case CXPrintingPolicy_SuppressImplicitBase:
+    // Ops, not yet there in clang 5.0 and we do not need it.
+    return;
+  case CXPrintingPolicy_FullyQualifiedName:
+    P->FullyQualifiedName = Value;
+    return;
+  }
+
+  assert(false && "Invalid CXPrintingPolicyProperty");
+}
+
+CXString clang_getCursorPrettyPrinted(CXCursor C, CXPrintingPolicy cxPolicy) {
+  if (clang_Cursor_isNull(C))
+    return cxstring::createEmpty();
+
+  if (clang_isDeclaration(C.kind)) {
+    const Decl *D = getCursorDecl(C);
+    if (!D)
+      return cxstring::createEmpty();
+
+    SmallString<128> Str;
+    llvm::raw_svector_ostream OS(Str);
+    PrintingPolicy *UserPolicy = static_cast<PrintingPolicy *>(cxPolicy);
+    D->print(OS, UserPolicy ? *UserPolicy
+                            : getCursorContext(C).getPrintingPolicy());
+
+    return cxstring::createDup(OS.str());
+  }
+
+  return cxstring::createEmpty();
+}
+
 CXString clang_getCursorDisplayName(CXCursor C) {
   if (!clang_isDeclaration(C.kind))
     return clang_getCursorSpelling(C);
diff --git a/tools/libclang/libclang.exports b/tools/libclang/libclang.exports
index 5d1b0224ef..67e4b4334b 100644
--- a/tools/libclang/libclang.exports
+++ b/tools/libclang/libclang.exports
@@ -178,6 +178,8 @@ clang_getCursorAvailability
 clang_getCursorCompletionString
 clang_getCursorDefinition
 clang_getCursorDisplayName
+clang_getCursorPrintingPolicy
+clang_getCursorPrettyPrinted
 clang_getCursorExtent
 clang_getCursorExceptionSpecificationType
 clang_getCursorKind
@@ -359,3 +361,6 @@ clang_EvalResult_isUnsignedInt
 clang_EvalResult_getAsDouble
 clang_EvalResult_getAsStr
 clang_EvalResult_dispose
+clang_PrintingPolicy_getProperty
+clang_PrintingPolicy_setProperty
+clang_PrintingPolicy_dispose
diff --git a/unittests/libclang/LibclangTest.cpp b/unittests/libclang/LibclangTest.cpp
index f2a96d6be6..342fbd5279 100644
--- a/unittests/libclang/LibclangTest.cpp
+++ b/unittests/libclang/LibclangTest.cpp
@@ -572,3 +572,35 @@ TEST_F(LibclangReparseTest, clang_parseTranslationUnit2FullArgv) {
   EXPECT_EQ(0U, clang_getNumDiagnostics(ClangTU));
   DisplayDiagnostics();
 }
+
+class LibclangPrintingPolicyTest : public LibclangParseTest {
+public:
+  CXPrintingPolicy Policy = nullptr;
+
+  void SetUp() override {
+    LibclangParseTest::SetUp();
+    std::string File = "file.cpp";
+    WriteFile(File, "int i;\n");
+    ClangTU = clang_parseTranslationUnit(Index, File.c_str(), nullptr, 0,
+                                         nullptr, 0, TUFlags);
+    CXCursor TUCursor = clang_getTranslationUnitCursor(ClangTU);
+    Policy = clang_getCursorPrintingPolicy(TUCursor);
+  }
+  void TearDown() override {
+    clang_PrintingPolicy_dispose(Policy);
+    LibclangParseTest::TearDown();
+  }
+};
+
+TEST_F(LibclangPrintingPolicyTest, SetAndGetProperties) {
+  for (unsigned Value = 0; Value < 2; ++Value) {
+    for (int I = 0; I < CXPrintingPolicy_LastProperty; ++I) {
+      auto Property = static_cast<enum CXPrintingPolicyProperty>(I);
+      if (Property == CXPrintingPolicy_ConstantsAsWritten || Property == CXPrintingPolicy_SuppressImplicitBase)
+          continue; // These are not yet in clang 5.0.
+
+      clang_PrintingPolicy_setProperty(Policy, Property, Value);
+      EXPECT_EQ(Value, clang_PrintingPolicy_getProperty(Policy, Property));
+    }
+  }
+}