file(GENERATE): Evaluate early to allow generating source files

The evaluation files must be known before cmTargetTraceDependencies
attempts to find them, but we must actually generate the files after
cmTargetTraceDependencies, as that can add to target SOURCES.  The
limitation is that the generated output name must not depend on the
SOURCES of a target if the generated file is used by that target.

Mark the output files as GENERATED so that trace dependencies does
not expect them to already exist in the filesystem.

Move the invokation of ForceLinkerLanguage in the Generate logic
to after the generated file names are known.  ForceLinkerLanguage
tries to determine the sources of a target (in order to determine
an already-known language) and otherwise fails to get information
about the generated file.

Test that the output of file(GENERATE) can be used as a target source
file and that accessing the target SOURCES in the name of the output
file is an error.  Accessing the TARGET_OBJECTS would be a similar
error if it was legal to use that generator expression in this
context.  That is not currently possible and is a different error
condition, so test the current error output as a reminder to change
the expected output if that becomes possible in the future.  Test
that generated rule files resulting from cmTargetTraceDependencies
appear in the SOURCES generated in the output file.

24 files changed, 176 insertions, 2 deletions

diff --git a/Source/cmGeneratorExpression.cxx b/Source/cmGeneratorExpression.cxx
index 09d02ea..bff6f5f 100644
--- a/Source/cmGeneratorExpression.cxx
+++ b/Source/cmGeneratorExpression.cxx
@@ -90,6 +90,7 @@ const char *cmCompiledGeneratorExpression::Evaluate(
   context.HadError = false;
   context.HadContextSensitiveCondition = false;
   context.HadHeadSensitiveCondition = false;
+  context.SourceSensitiveTargets.clear();
   context.HeadTarget = headTarget;
   context.EvaluateForBuildsystem = this->EvaluateForBuildsystem;
   context.CurrentTarget = currentTarget ? currentTarget : headTarget;
@@ -118,6 +119,7 @@ const char *cmCompiledGeneratorExpression::Evaluate(
     {
     this->HadContextSensitiveCondition = context.HadContextSensitiveCondition;
     this->HadHeadSensitiveCondition = context.HadHeadSensitiveCondition;
+    this->SourceSensitiveTargets = context.SourceSensitiveTargets;
     }
 
   this->DependTargets = context.DependTargets;
diff --git a/Source/cmGeneratorExpression.h b/Source/cmGeneratorExpression.h
index b952520..57f78c5 100644
--- a/Source/cmGeneratorExpression.h
+++ b/Source/cmGeneratorExpression.h
@@ -115,6 +115,10 @@ public:
   {
     return this->HadHeadSensitiveCondition;
   }
+  std::set<cmTarget const*> GetSourceSensitiveTargets() const
+  {
+    return this->SourceSensitiveTargets;
+  }
 
   void SetEvaluateForBuildsystem(bool eval)
   {
@@ -146,6 +150,7 @@ private:
   mutable std::string Output;
   mutable bool HadContextSensitiveCondition;
   mutable bool HadHeadSensitiveCondition;
+  mutable std::set<cmTarget const*>  SourceSensitiveTargets;
   bool EvaluateForBuildsystem;
 };
 
diff --git a/Source/cmGeneratorExpressionEvaluationFile.cxx b/Source/cmGeneratorExpressionEvaluationFile.cxx
index 3a8dc48..1a101dd 100644
--- a/Source/cmGeneratorExpressionEvaluationFile.cxx
+++ b/Source/cmGeneratorExpressionEvaluationFile.cxx
@@ -13,6 +13,9 @@
 #include "cmGeneratorExpressionEvaluationFile.h"
 
 #include "cmMakefile.h"
+#include "cmLocalGenerator.h"
+#include "cmGlobalGenerator.h"
+#include "cmSourceFile.h"
 #include "cmGeneratedFileStream.h"
 #include <cmsys/FStream.hxx>
 
@@ -90,6 +93,20 @@ void cmGeneratorExpressionEvaluationFile::Generate(const std::string& config,
 }
 
 //----------------------------------------------------------------------------
+void cmGeneratorExpressionEvaluationFile::CreateOutputFile(
+                                              std::string const& config)
+{
+  std::string name = this->OutputFileExpr->Evaluate(this->Makefile, config);
+  cmSourceFile* sf = this->Makefile->GetOrCreateSource(name);
+  sf->SetProperty("GENERATED", "1");
+
+  cmGlobalGenerator *gg
+                  = this->Makefile->GetLocalGenerator()->GetGlobalGenerator();
+  gg->SetFilenameTargetDepends(sf,
+                          this->OutputFileExpr->GetSourceSensitiveTargets());
+}
+
+//----------------------------------------------------------------------------
 void cmGeneratorExpressionEvaluationFile::Generate()
 {
   mode_t perm = 0;
diff --git a/Source/cmGeneratorExpressionEvaluationFile.h b/Source/cmGeneratorExpressionEvaluationFile.h
index 4e87a88..3394ade 100644
--- a/Source/cmGeneratorExpressionEvaluationFile.h
+++ b/Source/cmGeneratorExpressionEvaluationFile.h
@@ -31,6 +31,8 @@ public:
 
   std::vector<std::string> GetFiles() const { return this->Files; }
 
+  void CreateOutputFile(std::string const& config);
+
 private:
   void Generate(const std::string& config,
               cmCompiledGeneratorExpression* inputExpression,
diff --git a/Source/cmGeneratorExpressionEvaluator.cxx b/Source/cmGeneratorExpressionEvaluator.cxx
index f62bdb6..9aa8e6f 100644
--- a/Source/cmGeneratorExpressionEvaluator.cxx
+++ b/Source/cmGeneratorExpressionEvaluator.cxx
@@ -950,6 +950,10 @@ static const struct TargetPropertyNode : public cmGeneratorExpressionNode
       // value for all evaluations.
       context->SeenTargetProperties.insert(propertyName);
       }
+    if (propertyName == "SOURCES")
+      {
+      context->SourceSensitiveTargets.insert(target);
+      }
 
     if (propertyName.empty())
       {
diff --git a/Source/cmGeneratorExpressionEvaluator.h b/Source/cmGeneratorExpressionEvaluator.h
index 8a529e8..0bf1797 100644
--- a/Source/cmGeneratorExpressionEvaluator.h
+++ b/Source/cmGeneratorExpressionEvaluator.h
@@ -31,6 +31,7 @@ struct cmGeneratorExpressionContext
   std::set<cmTarget*> DependTargets;
   std::set<cmTarget const*> AllTargets;
   std::set<std::string> SeenTargetProperties;
+  std::set<cmTarget const*> SourceSensitiveTargets;
   std::map<cmTarget const*, std::map<std::string, std::string> >
                                                           MaxLanguageStandard;
   cmMakefile *Makefile;
diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 1d1225f..5836a27 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -646,6 +646,17 @@ cmTargetTraceDependencies
           si != sources.end(); ++si)
         {
         cmSourceFile* sf = *si;
+        const std::set<cmTarget const*> tgts =
+                          this->GlobalGenerator->GetFilenameTargetDepends(sf);
+        if (tgts.find(this->Target) != tgts.end())
+          {
+          cmOStringStream e;
+          e << "Evaluation output file\n  \"" << sf->GetFullPath()
+            << "\"\ndepends on the sources of a target it is used in.  This "
+              "is a dependency loop and is not allowed.";
+          this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
+          return;
+          }
         if(emitted.insert(sf).second && this->SourcesQueued.insert(sf).second)
           {
           this->SourceQueue.push(sf);
diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index a729c3d..26cfdbe 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -1253,8 +1253,6 @@ void cmGlobalGenerator::Generate()
   // Create per-target generator information.
   this->CreateGeneratorTargets();
 
-  this->ForceLinkerLanguages();
-
 #ifdef CMAKE_BUILD_WITH_CMAKE
   for (AutogensType::iterator it = autogens.begin(); it != autogens.end();
        ++it)
@@ -1270,6 +1268,8 @@ void cmGlobalGenerator::Generate()
     this->LocalGenerators[i]->TraceDependencies();
     }
 
+  this->ForceLinkerLanguages();
+
   // Compute the manifest of main targets generated.
   for (i = 0; i < this->LocalGenerators.size(); ++i)
     {
@@ -2983,6 +2983,32 @@ std::string cmGlobalGenerator::EscapeJSON(const std::string& s) {
 }
 
 //----------------------------------------------------------------------------
+void cmGlobalGenerator::SetFilenameTargetDepends(cmSourceFile* sf,
+                                              std::set<cmTarget const*> tgts)
+{
+  this->FilenameTargetDepends[sf] = tgts;
+}
+
+//----------------------------------------------------------------------------
+std::set<cmTarget const*> const&
+cmGlobalGenerator::GetFilenameTargetDepends(cmSourceFile* sf) const {
+  return this->FilenameTargetDepends[sf];
+}
+
+//----------------------------------------------------------------------------
+void cmGlobalGenerator::CreateEvaluationSourceFiles(
+                                              std::string const& config) const
+{
+  for(std::vector<cmGeneratorExpressionEvaluationFile*>::const_iterator
+      li = this->EvaluationFiles.begin();
+      li != this->EvaluationFiles.end();
+      ++li)
+    {
+    (*li)->CreateOutputFile(config);
+    }
+}
+
+//----------------------------------------------------------------------------
 void cmGlobalGenerator::AddEvaluationFile(const std::string &inputFile,
                     cmsys::auto_ptr<cmCompiledGeneratorExpression> outputExpr,
                     cmMakefile *makefile,
diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index ddd7e91..8a10d38 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -341,6 +341,13 @@ public:
 
   bool GenerateCPackPropertiesFile();
 
+  void CreateEvaluationSourceFiles(std::string const& config) const;
+
+  void SetFilenameTargetDepends(cmSourceFile* sf,
+                                std::set<cmTarget const*> tgts);
+  std::set<cmTarget const*> const&
+  GetFilenameTargetDepends(cmSourceFile* sf) const;
+
 protected:
   virtual void Generate();
 
@@ -488,6 +495,9 @@ private:
 
   // track targets to issue CMP0042 warning for.
   std::set<std::string> CMP0042WarnTargets;
+
+  mutable std::map<cmSourceFile*, std::set<cmTarget const*> >
+  FilenameTargetDepends;
 };
 
 #endif
diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 69b56c6..3fb1e1e 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -259,6 +259,17 @@ void cmLocalGenerator::ConfigureFinalPass()
 
 void cmLocalGenerator::TraceDependencies()
 {
+  std::vector<std::string> configs;
+  this->Makefile->GetConfigurations(configs);
+  if (configs.empty())
+    {
+    configs.push_back("");
+    }
+  for(std::vector<std::string>::const_iterator ci = configs.begin();
+      ci != configs.end(); ++ci)
+    {
+    this->GlobalGenerator->CreateEvaluationSourceFiles(*ci);
+    }
   // Generate the rule files for each target.
   cmGeneratorTargetsType targets = this->Makefile->GetGeneratorTargets();
   for(cmGeneratorTargetsType::iterator t = targets.begin();
diff --git a/Tests/RunCMake/File_Generate/GenerateSource-result.txt b/Tests/RunCMake/File_Generate/GenerateSource-result.txt
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/GenerateSource-result.txt
@@ -0,0 +1 @@
+0
diff --git a/Tests/RunCMake/File_Generate/GenerateSource-stderr.txt b/Tests/RunCMake/File_Generate/GenerateSource-stderr.txt
new file mode 100644
index 0000000..10f3293
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/GenerateSource-stderr.txt
@@ -0,0 +1 @@
+^$
diff --git a/Tests/RunCMake/File_Generate/GenerateSource.cmake b/Tests/RunCMake/File_Generate/GenerateSource.cmake
new file mode 100644
index 0000000..147a7f6
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/GenerateSource.cmake
@@ -0,0 +1,12 @@
+
+enable_language(CXX)
+
+# Ensure re-generation
+file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/main.cpp")
+
+file(GENERATE
+  OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/main.cpp"
+  CONTENT "int main() { return 0; }\n"
+)
+
+add_executable(mn "${CMAKE_CURRENT_BINARY_DIR}/main.cpp")
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesObjects-result.txt b/Tests/RunCMake/File_Generate/OutputNameMatchesObjects-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesObjects-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesObjects-stderr.txt b/Tests/RunCMake/File_Generate/OutputNameMatchesObjects-stderr.txt
new file mode 100644
index 0000000..d3aa973
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesObjects-stderr.txt
@@ -0,0 +1,9 @@
+CMake Error at OutputNameMatchesObjects.cmake:2 \(file\):
+  Error evaluating generator expression:
+
+    \$<TARGET_OBJECTS:foo>
+
+  The evaluation of the TARGET_OBJECTS generator expression is only suitable
+  for consumption by CMake.  It is not suitable for writing out elsewhere.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:6 \(include\)
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesObjects.cmake b/Tests/RunCMake/File_Generate/OutputNameMatchesObjects.cmake
new file mode 100644
index 0000000..d807450
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesObjects.cmake
@@ -0,0 +1,10 @@
+
+file(GENERATE
+  OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/$<BOOL:$<TARGET_OBJECTS:foo>>somefile.cpp"
+  CONTENT "static const char content[] = \"$<TARGET_OBJECTS:foo>\";\n"
+)
+
+add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/input.txt"
+  COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_CURRENT_SOURCE_DIR}/input.txt" "${CMAKE_CURRENT_BINARY_DIR}")
+
+add_executable(foo empty.cpp "${CMAKE_CURRENT_BINARY_DIR}/1somefile.cpp" "${CMAKE_CURRENT_BINARY_DIR}/input.txt")
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources-result.txt b/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources-result.txt
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources-result.txt
@@ -0,0 +1 @@
+0
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources-stderr.txt b/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources-stderr.txt
new file mode 100644
index 0000000..10f3293
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources-stderr.txt
@@ -0,0 +1 @@
+^$
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources.cmake b/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources.cmake
new file mode 100644
index 0000000..ce601da
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesOtherSources.cmake
@@ -0,0 +1,14 @@
+
+enable_language(CXX)
+
+file(GENERATE
+  OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/$<BOOL:$<TARGET_PROPERTY:foo,SOURCES>>somefile.cpp"
+  CONTENT "static const char content[] = \"$<TARGET_PROPERTY:foo,SOURCES>\";\n"
+)
+
+add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/generated.cpp"
+  COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_CURRENT_SOURCE_DIR}/generated.cpp" "${CMAKE_CURRENT_BINARY_DIR}")
+
+add_executable(foo empty.cpp "${CMAKE_CURRENT_BINARY_DIR}/generated.cpp")
+
+add_executable(bar "${CMAKE_CURRENT_BINARY_DIR}/1somefile.cpp")
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesSources-result.txt b/Tests/RunCMake/File_Generate/OutputNameMatchesSources-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesSources-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesSources-stderr.txt b/Tests/RunCMake/File_Generate/OutputNameMatchesSources-stderr.txt
new file mode 100644
index 0000000..cefb4e5
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesSources-stderr.txt
@@ -0,0 +1,7 @@
+CMake Error in CMakeLists.txt:
+  Evaluation output file
+
+    ".*Tests/RunCMake/File_Generate/OutputNameMatchesSources-build/1somefile.cpp"
+
+  depends on the sources of a target it is used in.  This is a dependency
+  loop and is not allowed.
diff --git a/Tests/RunCMake/File_Generate/OutputNameMatchesSources.cmake b/Tests/RunCMake/File_Generate/OutputNameMatchesSources.cmake
new file mode 100644
index 0000000..2feb9d1
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/OutputNameMatchesSources.cmake
@@ -0,0 +1,12 @@
+
+enable_language(CXX)
+
+file(GENERATE
+  OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/$<BOOL:$<TARGET_PROPERTY:foo,SOURCES>>somefile.cpp"
+  CONTENT "static const char content[] = \"$<TARGET_PROPERTY:foo,SOURCES>\";\n"
+)
+
+add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/renamed.cpp"
+  COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_CURRENT_SOURCE_DIR}/empty.cpp" "${CMAKE_CURRENT_BINARY_DIR}/renamed.cpp")
+
+add_executable(foo "${CMAKE_CURRENT_BINARY_DIR}/1somefile.cpp" "${CMAKE_CURRENT_BINARY_DIR}/renamed.cpp")
diff --git a/Tests/RunCMake/File_Generate/RunCMakeTest.cmake b/Tests/RunCMake/File_Generate/RunCMakeTest.cmake
index 578df81..7db77d4 100644
--- a/Tests/RunCMake/File_Generate/RunCMakeTest.cmake
+++ b/Tests/RunCMake/File_Generate/RunCMakeTest.cmake
@@ -8,6 +8,14 @@ run_cmake(EmptyCondition1)
 run_cmake(EmptyCondition2)
 run_cmake(BadCondition)
 run_cmake(DebugEvaluate)
+run_cmake(GenerateSource)
+run_cmake(OutputNameMatchesSources)
+run_cmake(OutputNameMatchesObjects)
+run_cmake(OutputNameMatchesOtherSources)
+file(READ "${RunCMake_BINARY_DIR}/OutputNameMatchesOtherSources-build/1somefile.cpp" file_contents)
+if (NOT file_contents MATCHES "generated.cpp.rule")
+  message(SEND_ERROR "Rule file not in target sources! ${file_contents}")
+endif()
 
 set(timeformat "%Y%j%H%M%S")
 
diff --git a/Tests/RunCMake/File_Generate/empty.cpp b/Tests/RunCMake/File_Generate/empty.cpp
new file mode 100644
index 0000000..bfbbdde
--- /dev/null
+++ b/Tests/RunCMake/File_Generate/empty.cpp
@@ -0,0 +1,7 @@
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int empty()
+{
+  return 0;
+}