Add default values for function parameter chunks

Append optional chunks with their default values. For example:
before - "int i", after - "int i = 10"

Patch by Ivan Donchevskii!
    
Differential Revision: https://reviews.llvm.org/D33644



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@308433 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaCodeComplete.cpp

@@ -2398,6 +2398,37 @@ formatBlockPlaceholder(const PrintingPolicy &Policy, const NamedDecl *BlockDecl,
   return Result;
 }
 
+static std::string GetDefaultValueString(const ParmVarDecl *Param,
+                                         const SourceManager &SM,
+                                         const LangOptions &LangOpts) {
+  const Expr *defaultArg = Param->getDefaultArg();
+  if (!defaultArg)
+    return "";
+  const SourceRange SrcRange = defaultArg->getSourceRange();
+  CharSourceRange CharSrcRange = CharSourceRange::getTokenRange(SrcRange);
+  bool Invalid = CharSrcRange.isInvalid();
+  if (Invalid)
+    return "";
+  StringRef srcText = Lexer::getSourceText(CharSrcRange, SM, LangOpts, &Invalid);
+  if (Invalid)
+    return "";
+
+  if (srcText.empty() || srcText == "=") {
+    // Lexer can't determine the value.
+    // This happens if the code is incorrect (for example class is forward declared).
+    return "";
+  }
+  std::string DefValue{srcText};
+  // FIXME: remove this check if the Lexer::getSourceText value is fixed and
+  // this value always has (or always does not have) '=' in front of it
+  if (DefValue.at(0) != '=') {
+    // If we don't have '=' in front of value.
+    // Lexer returns built-in types values without '=' and user-defined types values with it.
+    return " = " + DefValue;
+  }
+  return " " + DefValue;
+}
+
 /// \brief Add function parameter chunks to the given code completion string.
 static void AddFunctionParameterChunks(Preprocessor &PP,
                                        const PrintingPolicy &Policy,
@@ -2431,6 +2462,8 @@ static void AddFunctionParameterChunks(Preprocessor &PP,
 
     // Format the placeholder string.
     std::string PlaceholderStr = FormatFunctionParameter(Policy, Param);
+    if (Param->hasDefaultArg())
+      PlaceholderStr += GetDefaultValueString(Param, PP.getSourceManager(), PP.getLangOpts());
 
     if (Function->isVariadic() && P == N - 1)
       PlaceholderStr += ", ...";
@@ -3012,10 +3045,14 @@ static void AddOverloadParameterChunks(ASTContext &Context,
 
     // Format the placeholder string.
     std::string Placeholder;
-    if (Function)
-      Placeholder = FormatFunctionParameter(Policy, Function->getParamDecl(P));
-    else
+    if (Function) {
+      const ParmVarDecl *Param = Function->getParamDecl(P);
+      Placeholder = FormatFunctionParameter(Policy, Param);
+      if (Param->hasDefaultArg())
+        Placeholder += GetDefaultValueString(Param, Context.getSourceManager(), Context.getLangOpts());
+    } else {
       Placeholder = Prototype->getParamType(P).getAsString(Policy);
+    }
 
     if (P == CurrentArg)
       Result.AddCurrentParameterChunk(

test/CodeCompletion/functions.cpp

@@ -4,5 +4,5 @@ void f(float x, float y...);
 void test() {
   ::
   // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:5:5 %s -o - | FileCheck -check-prefix=CHECK-CC1 %s
-  // CHECK-CC1: f(<#int i#>{#, <#int j#>{#, <#int k#>#}#})
+  // CHECK-CC1: f(<#int i#>{#, <#int j = 2#>{#, <#int k = 5#>#}#})
   // CHECK-CC1: f(<#float x#>, <#float y, ...#>)

test/Index/code-completion.cpp

@@ -40,7 +40,7 @@ Z::operator int() const {
 // CHECK-MEMBER: FieldDecl:{ResultType double}{TypedText member}
 // CHECK-MEMBER: FieldDecl:{ResultType int}{Text X::}{TypedText member}
 // CHECK-MEMBER: FieldDecl:{ResultType float}{Text Y::}{TypedText member}
-// CHECK-MEMBER: CXXMethod:{ResultType void}{Informative Y::}{TypedText memfunc}{LeftParen (}{Optional {Placeholder int i}}{RightParen )}
+// CHECK-MEMBER: CXXMethod:{ResultType void}{Informative Y::}{TypedText memfunc}{LeftParen (}{Optional {Placeholder int i = 17}}{RightParen )}
 // CHECK-MEMBER: CXXConversion:{TypedText operator int}{LeftParen (}{RightParen )}{Informative  const}
 // CHECK-MEMBER: CXXMethod:{ResultType Z &}{TypedText operator=}{LeftParen (}{Placeholder const Z &}{RightParen )}
 // CHECK-MEMBER: CXXMethod:{ResultType X &}{Text X::}{TypedText operator=}{LeftParen (}{Placeholder const X &}{RightParen )}
@@ -77,7 +77,7 @@ Z::operator int() const {
 // CHECK-EXPR: FieldDecl:{ResultType double}{TypedText member} (17)
 // CHECK-EXPR: FieldDecl:{ResultType int}{Text X::}{TypedText member} (9)
 // CHECK-EXPR: FieldDecl:{ResultType float}{Text Y::}{TypedText member} (18)
-// CHECK-EXPR: CXXMethod:{ResultType void}{TypedText memfunc}{LeftParen (}{Optional {Placeholder int i}}{RightParen )} (37)
+// CHECK-EXPR: CXXMethod:{ResultType void}{TypedText memfunc}{LeftParen (}{Optional {Placeholder int i = 17}}{RightParen )} (37)
 // CHECK-EXPR: Namespace:{TypedText N}{Text ::} (75)
 // CHECK-EXPR: Completion contexts:
 // CHECK-EXPR-NEXT: Any type

test/Index/complete-optional-params.cpp

@@ -6,15 +6,19 @@ void bar(int a, int b = 42, int c = 42);
 void baz(int a = 42, ...);
 struct S{ S(int a = 42, int = 42) {} };
 
+class Bar1 { public: Bar1() {} }; class Bar2;
+void foo_2(Bar1 b1 = Bar1(), Bar2 b2 = Bar2());
+
 int main() {
     foo(42, 42);
     bar(42, 42, 42);
     baz(42, 42, 42);
     S s(42, 42);
+    foo_2();
 }
 
-// RUN: c-index-test -code-completion-at=%s:10:9 %s | FileCheck -check-prefix=CHECK-CC1 %s
-// CHECK-CC1: OverloadCandidate:{ResultType void}{Text foo}{LeftParen (}{Optional {CurrentParameter int a}{Optional {Comma , }{Placeholder int}}}{RightParen )} (1)
+// RUN: c-index-test -code-completion-at=%s:13:9 %s | FileCheck -check-prefix=CHECK-CC1 %s
+// CHECK-CC1: OverloadCandidate:{ResultType void}{Text foo}{LeftParen (}{Optional {CurrentParameter int a = 42}{Optional {Comma , }{Placeholder int = 42}}}{RightParen )} (1)
 // CHECK-CC1: Completion contexts:
 // CHECK-CC1-NEXT: Any type
 // CHECK-CC1-NEXT: Any value
@@ -25,8 +29,8 @@ int main() {
 // CHECK-CC1-NEXT: Nested name specifier
 // CHECK-CC1-NEXT: Objective-C interface
 
-// RUN: c-index-test -code-completion-at=%s:11:9 %s | FileCheck -check-prefix=CHECK-CC2 %s
-// CHECK-CC2: OverloadCandidate:{ResultType void}{Text bar}{LeftParen (}{CurrentParameter int a}{Optional {Comma , }{Placeholder int b}{Optional {Comma , }{Placeholder int c}}}{RightParen )} (1)
+// RUN: c-index-test -code-completion-at=%s:14:9 %s | FileCheck -check-prefix=CHECK-CC2 %s
+// CHECK-CC2: OverloadCandidate:{ResultType void}{Text bar}{LeftParen (}{CurrentParameter int a}{Optional {Comma , }{Placeholder int b = 42}{Optional {Comma , }{Placeholder int c = 42}}}{RightParen )} (1)
 // CHECK-CC2: Completion contexts:
 // CHECK-CC2-NEXT: Any type
 // CHECK-CC2-NEXT: Any value
@@ -37,8 +41,8 @@ int main() {
 // CHECK-CC2-NEXT: Nested name specifier
 // CHECK-CC2-NEXT: Objective-C interface
 
-// RUN: c-index-test -code-completion-at=%s:11:16 %s | FileCheck -check-prefix=CHECK-CC3 %s
-// CHECK-CC3: OverloadCandidate:{ResultType void}{Text bar}{LeftParen (}{Placeholder int a}{Optional {Comma , }{Placeholder int b}{Optional {Comma , }{CurrentParameter int c}}}{RightParen )} (1)
+// RUN: c-index-test -code-completion-at=%s:14:16 %s | FileCheck -check-prefix=CHECK-CC3 %s
+// CHECK-CC3: OverloadCandidate:{ResultType void}{Text bar}{LeftParen (}{Placeholder int a}{Optional {Comma , }{Placeholder int b = 42}{Optional {Comma , }{CurrentParameter int c = 42}}}{RightParen )} (1)
 // CHECK-CC3: Completion contexts:
 // CHECK-CC3-NEXT: Any type
 // CHECK-CC3-NEXT: Any value
@@ -49,8 +53,8 @@ int main() {
 // CHECK-CC3-NEXT: Nested name specifier
 // CHECK-CC3-NEXT: Objective-C interface
 
-// RUN: c-index-test -code-completion-at=%s:12:16 %s | FileCheck -check-prefix=CHECK-CC4 %s
-// CHECK-CC4: OverloadCandidate:{ResultType void}{Text baz}{LeftParen (}{Optional {Placeholder int a}{Optional {Comma , }{CurrentParameter ...}}}{RightParen )} (1)
+// RUN: c-index-test -code-completion-at=%s:15:16 %s | FileCheck -check-prefix=CHECK-CC4 %s
+// CHECK-CC4: OverloadCandidate:{ResultType void}{Text baz}{LeftParen (}{Optional {Placeholder int a = 42}{Optional {Comma , }{CurrentParameter ...}}}{RightParen )} (1)
 // CHECK-CC4: Completion contexts:
 // CHECK-CC4-NEXT: Any type
 // CHECK-CC4-NEXT: Any value
@@ -61,8 +65,8 @@ int main() {
 // CHECK-CC4-NEXT: Nested name specifier
 // CHECK-CC4-NEXT: Objective-C interface
 
-// RUN: c-index-test -code-completion-at=%s:13:9 %s | FileCheck -check-prefix=CHECK-CC5 %s
-// CHECK-CC5: OverloadCandidate:{Text S}{LeftParen (}{Optional {CurrentParameter int a}{Optional {Comma , }{Placeholder int}}}{RightParen )} (1)
+// RUN: c-index-test -code-completion-at=%s:16:9 %s | FileCheck -check-prefix=CHECK-CC5 %s
+// CHECK-CC5: OverloadCandidate:{Text S}{LeftParen (}{Optional {CurrentParameter int a = 42}{Optional {Comma , }{Placeholder int = 42}}}{RightParen )} (1)
 // CHECK-CC5: OverloadCandidate:{Text S}{LeftParen (}{CurrentParameter const S &}{RightParen )} (1)
 // CHECK-CC5: Completion contexts:
 // CHECK-CC5-NEXT: Any type
@@ -73,3 +77,15 @@ int main() {
 // CHECK-CC5-NEXT: Class name
 // CHECK-CC5-NEXT: Nested name specifier
 // CHECK-CC5-NEXT: Objective-C interface
+
+// RUN: c-index-test -code-completion-at=%s:17:11 %s | FileCheck -check-prefix=CHECK-CC6 %s
+// CHECK-CC6: FunctionDecl:{ResultType void}{TypedText foo_2}{LeftParen (}{Optional {Placeholder Bar1 b1 = Bar1()}{Optional {Comma , }{Placeholder Bar2 b2}}}{RightParen )} (50)
+// CHECK-CC6: Completion contexts:
+// CHECK-CC6-NEXT: Any type
+// CHECK-CC6-NEXT: Any value
+// CHECK-CC6-NEXT: Enum tag
+// CHECK-CC6-NEXT: Union tag
+// CHECK-CC6-NEXT: Struct tag
+// CHECK-CC6-NEXT: Class name
+// CHECK-CC6-NEXT: Nested name specifier
+// CHECK-CC6-NEXT: Objective-C interface