Introduce the INTERFACE_LINK_LIBRARIES property.

This property replaces the properties which
match (IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?, and is enabled
for IMPORTED targets, and for non-IMPORTED targets only with a policy.

For static libraries, the INTERFACE_LINK_LIBRARIES property is
also used as the source of transitive usage requirements content.
Static libraries still require users to link to all entries in
their LINK_LIBRARIES, but usage requirements such as INCLUDE_DIRECTORIES
COMPILE_DEFINITIONS and COMPILE_OPTIONS can be restricted to only
certain interface libraries.

Because the INTERFACE_LINK_LIBRARIES property is populated unconditionally,
we need to compare the evaluated result of it with the link implementation
to determine whether to issue the policy warning for static libraries. For
shared libraries, the policy warning is issued if the contents of
the INTERFACE_LINK_LIBRARIES property differs from the contents of the
relevant config-specific old LINK_INTERFACE_LIBRARIES property.

Tests/InterfaceLinkLibraries/CMakeLists.txt

@@ -0,0 +1,49 @@
+cmake_minimum_required (VERSION 2.8)
+
+cmake_policy(SET CMP0022 NEW)
+
+project(InterfaceLinkLibraries)
+
+add_library(foo_shared SHARED foo_vs6_1.cpp)
+target_compile_definitions(foo_shared INTERFACE FOO_LIBRARY)
+add_library(bar_shared SHARED bar_vs6_1.cpp)
+target_compile_definitions(bar_shared INTERFACE BAR_LIBRARY)
+set_property(TARGET bar_shared APPEND PROPERTY INTERFACE_LINK_LIBRARIES foo_shared)
+
+add_executable(shared_test main_vs6_1.cpp)
+set_property(TARGET shared_test APPEND PROPERTY LINK_LIBRARIES bar_shared)
+
+add_library(foo_static STATIC foo_vs6_2.cpp)
+target_compile_definitions(foo_static INTERFACE FOO_LIBRARY)
+add_library(bar_static STATIC bar_vs6_2.cpp)
+target_compile_definitions(bar_static INTERFACE BAR_LIBRARY)
+set_property(TARGET bar_static APPEND PROPERTY INTERFACE_LINK_LIBRARIES foo_static)
+
+add_executable(static_test main_vs6_2.cpp)
+set_property(TARGET static_test APPEND PROPERTY LINK_LIBRARIES bar_static)
+
+add_library(foo_shared_private SHARED foo_vs6_3.cpp)
+target_compile_definitions(foo_shared_private INTERFACE FOO_LIBRARY)
+add_library(bang_shared_private SHARED bang_vs6_1.cpp)
+target_compile_definitions(bang_shared_private INTERFACE BANG_LIBRARY)
+add_library(bar_shared_private SHARED bar_vs6_3.cpp)
+target_compile_definitions(bar_shared_private INTERFACE BAR_LIBRARY)
+target_compile_definitions(bar_shared_private PRIVATE BAR_USE_BANG)
+set_property(TARGET bar_shared_private APPEND PROPERTY LINK_LIBRARIES bang_shared_private)
+set_property(TARGET bar_shared_private APPEND PROPERTY INTERFACE_LINK_LIBRARIES foo_shared_private)
+
+add_executable(shared_private_test main_vs6_3.cpp)
+set_property(TARGET shared_private_test APPEND PROPERTY LINK_LIBRARIES bar_shared_private)
+
+add_library(foo_static_private STATIC foo_vs6_4.cpp)
+target_compile_definitions(foo_static_private INTERFACE FOO_LIBRARY)
+add_library(bang_static_private STATIC bang_vs6_2.cpp)
+target_compile_definitions(bang_static_private INTERFACE BANG_LIBRARY)
+add_library(bar_static_private STATIC bar_vs6_4.cpp)
+target_compile_definitions(bar_static_private INTERFACE BAR_LIBRARY)
+target_compile_definitions(bar_static_private PRIVATE BAR_USE_BANG)
+set_property(TARGET bar_static_private APPEND PROPERTY LINK_LIBRARIES bang_static_private)
+set_property(TARGET bar_static_private APPEND PROPERTY INTERFACE_LINK_LIBRARIES $<LINK_ONLY:bang_static_private> foo_static_private)
+
+add_executable(InterfaceLinkLibraries main_vs6_4.cpp)
+set_property(TARGET InterfaceLinkLibraries APPEND PROPERTY LINK_LIBRARIES bar_static_private)

Tests/InterfaceLinkLibraries/bang.cpp

@@ -0,0 +1,15 @@
+
+#ifdef FOO_LIBRARY
+#error Unexpected FOO_LIBRARY
+#endif
+
+#ifdef BAR_LIBRARY
+#error Unexpected BAR_LIBRARY
+#endif
+
+#include "bang.h"
+
+int bang()
+{
+  return 0;
+}

Tests/InterfaceLinkLibraries/bang.h

@@ -0,0 +1,4 @@
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int bang();

Tests/InterfaceLinkLibraries/bang_vs6_1.cpp

@@ -0,0 +1 @@
+#include "bang.cpp"

Tests/InterfaceLinkLibraries/bang_vs6_2.cpp

@@ -0,0 +1 @@
+#include "bang.cpp"

Tests/InterfaceLinkLibraries/bar.cpp

@@ -0,0 +1,26 @@
+
+#ifdef FOO_LIBRARY
+#error Unexpected FOO_LIBRARY
+#endif
+
+#ifdef BAR_USE_BANG
+#  ifndef BANG_LIBRARY
+#    error Expected BANG_LIBRARY
+#  endif
+#  include "bang.h"
+#else
+#  ifdef BANG_LIBRARY
+#    error Unexpected BANG_LIBRARY
+#  endif
+#endif
+
+#include "bar.h"
+
+int bar()
+{
+#ifdef BAR_USE_BANG
+  return bang();
+#else
+  return 0;
+#endif
+}

Tests/InterfaceLinkLibraries/bar.h

@@ -0,0 +1,7 @@
+
+#include "foo.h"
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int bar();

Tests/InterfaceLinkLibraries/bar_vs6_1.cpp

@@ -0,0 +1 @@
+#include "bar.cpp"

Tests/InterfaceLinkLibraries/bar_vs6_2.cpp

@@ -0,0 +1 @@
+#include "bar.cpp"

Tests/InterfaceLinkLibraries/bar_vs6_3.cpp

@@ -0,0 +1 @@
+#include "bar.cpp"

Tests/InterfaceLinkLibraries/bar_vs6_4.cpp

@@ -0,0 +1 @@
+#include "bar.cpp"

Tests/InterfaceLinkLibraries/foo.cpp

@@ -0,0 +1,15 @@
+
+#ifdef BAR_LIBRARY
+#error Unexpected BAR_LIBRARY
+#endif
+
+#ifdef BANG_LIBRARY
+#error Unexpected BANG_LIBRARY
+#endif
+
+#include "foo.h"
+
+int foo()
+{
+  return 0;
+}

Tests/InterfaceLinkLibraries/foo.h

@@ -0,0 +1,4 @@
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int foo();

Tests/InterfaceLinkLibraries/foo_vs6_1.cpp

@@ -0,0 +1 @@
+#include "foo.cpp"

Tests/InterfaceLinkLibraries/foo_vs6_2.cpp

@@ -0,0 +1 @@
+#include "foo.cpp"

Tests/InterfaceLinkLibraries/foo_vs6_3.cpp

@@ -0,0 +1 @@
+#include "foo.cpp"

Tests/InterfaceLinkLibraries/foo_vs6_4.cpp

@@ -0,0 +1 @@
+#include "foo.cpp"

Tests/InterfaceLinkLibraries/main.cpp

@@ -0,0 +1,19 @@
+
+#ifndef FOO_LIBRARY
+#error Expected FOO_LIBRARY
+#endif
+
+#ifndef BAR_LIBRARY
+#error Expected BAR_LIBRARY
+#endif
+
+#ifdef BANG_LIBRARY
+#error Unexpected BANG_LIBRARY
+#endif
+
+#include "bar.h"
+
+int main(void)
+{
+  return foo() + bar();
+}

Tests/InterfaceLinkLibraries/main_vs6_1.cpp

@@ -0,0 +1 @@
+#include "main.cpp"

Tests/InterfaceLinkLibraries/main_vs6_2.cpp

@@ -0,0 +1 @@
+#include "main.cpp"

Tests/InterfaceLinkLibraries/main_vs6_3.cpp

@@ -0,0 +1 @@
+#include "main.cpp"

Tests/InterfaceLinkLibraries/main_vs6_4.cpp

@@ -0,0 +1 @@
+#include "main.cpp"