From 2bee6f5ba5b3f33817cc00e056a7df60d05c9399 Mon Sep 17 00:00:00 2001
From: Stephen Kelly <steveire@gmail.com>
Date: Mon, 19 Nov 2012 23:56:12 +0100
Subject: Add the TARGET_DEFINED generator expression

This tests whether the parameter is a usable target.
---
 Source/cmDocumentGeneratorExpressions.h                |  1 +
 Source/cmGeneratorExpressionEvaluator.cxx              | 18 ++++++++++++++++++
 .../target_compile_definitions/CMakeLists.txt          |  2 ++
 .../target_compile_definitions/consumer.cpp            |  8 ++++++++
 4 files changed, 29 insertions(+)

diff --git a/Source/cmDocumentGeneratorExpressions.h b/Source/cmDocumentGeneratorExpressions.h
index b8889ac..fa21907 100644
--- a/Source/cmDocumentGeneratorExpressions.h
+++ b/Source/cmDocumentGeneratorExpressions.h
@@ -37,6 +37,7 @@
   "target in the same buildsystem. Expands to the empty string "        \
   "otherwise.\n"                                                        \
   "  $<TARGET_FILE:tgt>        = main file (.exe, .so.1.2, .a)\n"       \
+  "  $<TARGET_DEFINED:tgt>     = '1' if tgt is a target, else '0'\n"    \
   "  $<TARGET_LINKER_FILE:tgt> = file used to link (.a, .lib, .so)\n"   \
   "  $<TARGET_SONAME_FILE:tgt> = file with soname (.so.3)\n"            \
   "where \"tgt\" is the name of a target.  "                            \
diff --git a/Source/cmGeneratorExpressionEvaluator.cxx b/Source/cmGeneratorExpressionEvaluator.cxx
index f4e4131..8e40815a 100644
--- a/Source/cmGeneratorExpressionEvaluator.cxx
+++ b/Source/cmGeneratorExpressionEvaluator.cxx
@@ -289,6 +289,22 @@ static const struct ConfigurationTestNode : public cmGeneratorExpressionNode
 } configurationTestNode;
 
 
+static const struct TargetDefinedNode : public cmGeneratorExpressionNode
+{
+  TargetDefinedNode() {}
+
+  virtual int NumExpectedParameters() const { return 1; }
+
+  std::string Evaluate(const std::vector<std::string> &parameters,
+                       cmGeneratorExpressionContext *context,
+                       const GeneratorExpressionContent *,
+                       cmGeneratorExpressionDAGChecker *) const
+  {
+    return context->Makefile->FindTargetToUse(parameters.front().c_str())
+      ? "1" : "0";
+  }
+} targetDefinedNode;
+
 //----------------------------------------------------------------------------
 static const char* targetPropertyTransitiveWhitelist[] = {
     "INTERFACE_INCLUDE_DIRECTORIES"
@@ -702,6 +718,8 @@ cmGeneratorExpressionNode* GetNode(const std::string &identifier)
     return &buildInterfaceNode;
   else if (identifier == "INSTALL_INTERFACE")
     return &installInterfaceNode;
+  else if (identifier == "TARGET_DEFINED")
+    return &targetDefinedNode;
   return 0;
 
 }
diff --git a/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt b/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
index 84a23ef..a37c597 100644
--- a/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
+++ b/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
@@ -23,4 +23,6 @@ add_executable(consumer
 
 target_compile_definitions(consumer
   PRIVATE target_compile_definitions importedlib
+  $<$<TARGET_DEFINED:notdefined>:SHOULD_NOT_BE_DEFINED>
+  $<$<TARGET_DEFINED:importedlib>:SHOULD_BE_DEFINED>
 )
diff --git a/Tests/CMakeCommands/target_compile_definitions/consumer.cpp b/Tests/CMakeCommands/target_compile_definitions/consumer.cpp
index e3788dd..1ef657d 100644
--- a/Tests/CMakeCommands/target_compile_definitions/consumer.cpp
+++ b/Tests/CMakeCommands/target_compile_definitions/consumer.cpp
@@ -15,4 +15,12 @@
 #error Expected MY_IMPORTEDINTERFACE_DEFINE
 #endif
 
+#ifdef SHOULD_NOT_BE_DEFINED
+#error Unexpected SHOULD_NOT_BE_DEFINED
+#endif
+
+#ifndef SHOULD_BE_DEFINED
+#error Expected SHOULD_BE_DEFINED
+#endif
+
 int main() { return 0; }
-- 
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