[clang-tidy] ClangTidy check to flag uninitialized builtin and pointer fields.

Summary:
This patch is a continuation of http://reviews.llvm.org/D10553 by Jonathan B Coe.

The main additions are:

1. For C++11 the check suggests in-class field initialization as fix. This
makes the fields future proof towards the addition of new constructors.
2 For older language versions the fields are added in the right position
in the initializer list with more tests.
3. User documentation.

Reviewers: alexfh, jbcoe

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D16517

2 files changed, 178 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-type-member-init-cxx98.cpp b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-type-member-init-cxx98.cpp
new file mode 100644
index 00000000000..164ab56637e
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-type-member-init-cxx98.cpp
@@ -0,0 +1,67 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-pro-type-member-init %t -- -- -std=c++98
+
+struct PositiveFieldBeforeConstructor {
+  int F;
+  PositiveFieldBeforeConstructor() /* some comment */ {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: F
+  // CHECK-FIXES: PositiveFieldBeforeConstructor() : F() /* some comment */ {}
+};
+
+struct PositiveFieldAfterConstructor {
+  PositiveFieldAfterConstructor() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: F, G, H
+  // CHECK-FIXES: PositiveFieldAfterConstructor() : F(), G(), H() {}
+  int F;
+  bool G /* with comment */;
+  int *H;
+  PositiveFieldBeforeConstructor IgnoredField;
+};
+
+struct PositiveSeparateDefinition {
+  PositiveSeparateDefinition();
+  int F;
+};
+
+PositiveSeparateDefinition::PositiveSeparateDefinition() {}
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: constructor does not initialize these built-in/pointer fields: F
+// CHECK-FIXES: PositiveSeparateDefinition::PositiveSeparateDefinition() : F() {}
+
+struct PositiveMixedFieldOrder {
+  PositiveMixedFieldOrder() : /* some comment */ J(0), L(0), M(0) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: I, K, N
+  // CHECK-FIXES: PositiveMixedFieldOrder() : I(), /* some comment */ J(0), K(), L(0), M(0), N() {}
+  int I;
+  int J;
+  int K;
+  int L;
+  int M;
+  int N;
+};
+
+struct PositiveAfterBaseInitializer : public PositiveMixedFieldOrder {
+  PositiveAfterBaseInitializer() : PositiveMixedFieldOrder() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: F
+  // CHECK-FIXES: PositiveAfterBaseInitializer() : PositiveMixedFieldOrder(), F() {}
+  int F;
+};
+
+struct NegativeFieldInitialized {
+  int F;
+
+  NegativeFieldInitialized() : F() {}
+};
+
+struct NegativeFieldInitializedInDefinition {
+  int F;
+
+  NegativeFieldInitializedInDefinition();
+};
+
+NegativeFieldInitializedInDefinition::NegativeFieldInitializedInDefinition() : F() {}
+
+struct NegativeInitializedInBody {
+  NegativeInitializedInBody() { I = 0; }
+  int I;
+};
+
+
diff --git a/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
new file mode 100644
index 00000000000..62e7319ee89
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-type-member-init.cpp
@@ -0,0 +1,111 @@
+// RUN: %check_clang_tidy %s cppcoreguidelines-pro-type-member-init %t
+
+struct PositiveFieldBeforeConstructor {
+  int F;
+  // CHECK-FIXES: int F{};
+  PositiveFieldBeforeConstructor() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: F
+  // CHECK-FIXES: PositiveFieldBeforeConstructor() {}
+};
+
+struct PositiveFieldAfterConstructor {
+  PositiveFieldAfterConstructor() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: F, G
+  // CHECK-FIXES: PositiveFieldAfterConstructor() {}
+  int F;
+  // CHECK-FIXES: int F{};
+  bool G /* with comment */;
+  // CHECK-FIXES: bool G{} /* with comment */;
+  PositiveFieldBeforeConstructor IgnoredField;
+};
+
+struct PositiveSeparateDefinition {
+  PositiveSeparateDefinition();
+  int F;
+  // CHECK-FIXES: int F{};
+};
+
+PositiveSeparateDefinition::PositiveSeparateDefinition() {}
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: constructor does not initialize these built-in/pointer fields: F
+// CHECK-FIXES: PositiveSeparateDefinition::PositiveSeparateDefinition() {}
+
+struct PositiveMixedFieldOrder {
+  PositiveMixedFieldOrder() : J(0) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: I, K
+  // CHECK-FIXES: PositiveMixedFieldOrder() : J(0) {}
+  int I;
+  // CHECK-FIXES: int I{};
+  int J;
+  int K;
+  // CHECK-FIXES: int K{};
+};
+
+template <typename T>
+struct Template {
+  Template() {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: constructor does not initialize these built-in/pointer fields: F
+  int F;
+  // CHECK-FIXES: int F{};
+  T T1;
+  // CHECK-FIXES: T T1;
+};
+
+void instantiate() {
+  Template<int> TInt;
+}
+
+struct NegativeFieldInitialized {
+  int F;
+
+  NegativeFieldInitialized() : F() {}
+};
+
+struct NegativeFieldInitializedInDefinition {
+  int F;
+
+  NegativeFieldInitializedInDefinition();
+};
+NegativeFieldInitializedInDefinition::NegativeFieldInitializedInDefinition() : F() {}
+
+
+struct NegativeInClassInitialized {
+  int F = 0;
+
+  NegativeInClassInitialized() {}
+};
+
+struct NegativeConstructorDelegated {
+  int F;
+
+  NegativeConstructorDelegated(int F) : F(F) {}
+  NegativeConstructorDelegated() : NegativeConstructorDelegated(0) {}
+};
+
+struct NegativeInitializedInBody {
+  NegativeInitializedInBody() { I = 0; }
+  int I;
+};
+
+#define UNINITIALIZED_FIELD_IN_MACRO_BODY(FIELD) \
+  struct UninitializedField##FIELD {		 \
+    UninitializedField##FIELD() {}		 \
+    int FIELD;					 \
+  };						 \
+// Ensure FIELD is not initialized since fixes inside of macros are disabled.
+// CHECK-FIXES: int FIELD;
+
+UNINITIALIZED_FIELD_IN_MACRO_BODY(F);
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: constructor does not initialize these built-in/pointer fields: F
+UNINITIALIZED_FIELD_IN_MACRO_BODY(G);
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: constructor does not initialize these built-in/pointer fields: G
+
+#define UNINITIALIZED_FIELD_IN_MACRO_ARGUMENT(ARGUMENT) \
+  ARGUMENT						\
+
+UNINITIALIZED_FIELD_IN_MACRO_ARGUMENT(struct UninitializedFieldInMacroArg {
+  UninitializedFieldInMacroArg() {}
+  int Field;
+});
+// CHECK-MESSAGES: :[[@LINE-3]]:3: warning: constructor does not initialize these built-in/pointer fields: Field
+// Ensure FIELD is not initialized since fixes inside of macros are disabled.
+// CHECK-FIXES: int Field;