Add support for __declspec(code_seg("segname"))

This patch uses CodeSegAttr to represent __declspec(code_seg) rather than 
building on the existing support for #pragma code_seg.
The code_seg declspec is applied on functions and classes. This attribute 
enables the placement of code into separate named segments, including compiler-
generated codes and template instantiations.

For more information, please see the following:
https://msdn.microsoft.com/en-us/library/dn636922.aspx

This patch fixes the regression for the support for attribute ((section).
https://github.com/llvm-mirror/clang/commit/746b78de7812bc785fbb5207b788348040b23fa7

Patch by Soumi Manna (Manna)
Differential Revision: https://reviews.llvm.org/D48841

llvm-svn: 337420

1 files changed, 105 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/code-seg.cpp b/clang/test/SemaCXX/code-seg.cpp
new file mode 100644
index 00000000000..c4ce6613ba9
--- /dev/null
+++ b/clang/test/SemaCXX/code-seg.cpp
@@ -0,0 +1,105 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -fms-extensions %s -triple x86_64-pc-win32
+
+struct __declspec(code_seg("my_one")) FooOne {
+  int barC();
+};
+
+struct FooTwo {
+  int __declspec(code_seg("my_three")) barD();
+  int barE();
+};
+int __declspec(code_seg("my_four")) FooOne::barC() { return 10; }
+// expected-warning@-1 {{codeseg does not match previous declaration}}
+// expected-note@3{{previous attribute is here}}
+int __declspec(code_seg("my_five")) FooTwo::barD() { return 20; }
+// expected-warning@-1 {{codeseg does not match previous declaration}}
+// expected-note@8 {{previous attribute is here}}
+int __declspec(code_seg("my_six")) FooTwo::barE() { return 30; }
+// expected-warning@-1 {{codeseg does not match previous declaration}}
+// expected-note@9 {{previous declaration is here}}
+
+// Microsoft docs say:
+// If a base-class has a code_seg attribute, derived classes must have the
+// same attribute.
+struct __declspec(code_seg("my_base")) Base1 {};
+struct Base2 {};
+
+struct D1 : Base1 {};
+//expected-error@-1 {{derived class must specify the same code segment as its base classes}}
+// expected-note@24 {{base class 'Base1' specified here}}
+struct __declspec(code_seg("my_derived")) D2 : Base1 {};
+// expected-error@-1 {{derived class must specify the same code segment as its base classes}}
+// expected-note@24 {{base class 'Base1' specified here}}
+struct __declspec(code_seg("my_derived")) D3 : Base2 {};
+// expected-error@-1 {{derived class must specify the same code segment as its base classes}}
+// expected-note@25 {{base class 'Base2' specified here}}
+
+template <typename T> struct __declspec(code_seg("my_base")) MB : T { };
+template <typename T> struct __declspec(code_seg("my_derived")) MD : T { };
+MB<Base1> mb1; // ok
+MB<Base2> mb2;
+// expected-error@37 {{derived class must specify the same code segment as its base classes}}
+// expected-note@-2 {{in instantiation of template class}}
+// expected-note@25  {{base class 'Base2' specified here}}
+MD<Base1> md1;
+// expected-error@38 {{derived class must specify the same code segment as its base classes}}
+// expected-note@-2 {{in instantiation of template class}}
+// expected-note@24 {{base class 'Base1' specified here}}
+MD<Base2> md2;
+// expected-error@38 {{derived class must specify the same code segment as its base classes}}
+// expected-note@-2 {{in instantiation of template class}}
+// expected-note@25 {{base class 'Base2' specified here}}
+
+// Virtual overrides must have the same code_seg.
+struct __declspec(code_seg("my_one")) Base3 {
+  virtual int barA() { return 1; }
+  virtual int __declspec(code_seg("my_two")) barB() { return 2; }
+};
+struct __declspec(code_seg("my_one")) Derived3 : Base3 {
+  int barA() { return 4; } // ok
+  int barB() { return 6; }
+  // expected-error@-1 {{overriding virtual function must specify the same code segment as its overridden function}}
+  // expected-note@56 {{previous declaration is here}}
+};
+
+struct Base4 {
+  virtual int __declspec(code_seg("my_one")) barA() {return 1;}
+  virtual int barB() { return 2;}
+};
+struct Derived4 : Base4 {
+  virtual int barA() {return 1;}
+  // expected-error@-1 {{overriding virtual function must specify the same code segment as its overridden function}}
+  // expected-note@66 {{previous declaration is here}}
+  virtual int __declspec(code_seg("my_two")) barB() {return 1;}
+  // expected-error@-1 {{overriding virtual function must specify the same code segment as its overridden function}}
+  // expected-note@67 {{previous declaration is here}}
+};
+
+// MS gives an error when different code segments are used but a warning when a duplicate is used
+
+// Function
+int __declspec(code_seg("foo")) __declspec(code_seg("foo")) bar1() { return 1; }
+// expected-warning@-1 {{duplicate code segment specifiers}}
+int __declspec(code_seg("foo")) __declspec(code_seg("bar")) bar2() { return 1; }
+// expected-error@-1 {{conflicting code segment specifiers}}
+
+// Class
+struct __declspec(code_seg("foo")) __declspec(code_seg("foo")) Foo {
+  // expected-warning@-1 {{duplicate code segment specifiers}}
+  int bar3() {return 0;}
+};
+struct __declspec(code_seg("foo")) __declspec(code_seg("bar")) FooSix {
+  // expected-error@-1 {{conflicting code segment specifiers}}
+  int bar3() {return 0;}
+};
+
+//Class Members
+struct FooThree {
+  int __declspec(code_seg("foo")) __declspec(code_seg("foo")) bar1() { return 1; }
+  // expected-warning@-1 {{duplicate code segment specifiers}}
+  int __declspec(code_seg("foo")) __declspec(code_seg("bar")) bar2() { return 1; }
+  // expected-error@-1 {{conflicting code segment specifiers}}
+  int bar8();
+  int bar9() { return 9; }
+};
+