find_*: Add debug logging infrastructure

Enable debug messages a new `--find-debug` command-line option or via
the `CMAKE_FIND_DEBUG_MODE` variable.

This work was started by Chris Wilson, continued by Ray Donnelly, and
then refactored by Robert Maynard to collect information into a single
message per find query.

Co-Author: Ray Donnelly <mingw.android@gmail.com>
Co-Author: Chris Wilson <chris+github@qwirx.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 74cc831..0ad482c 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -3728,7 +3728,8 @@ void cmMakefile::DisplayStatus(const std::string& message, float s) const
 }
 
 std::string cmMakefile::GetModulesFile(const std::string& filename,
-                                       bool& system) const
+                                       bool& system, bool debug,
+                                       std::string& debugBuffer) const
 {
   std::string result;
 
@@ -3759,6 +3760,9 @@ std::string cmMakefile::GetModulesFile(const std::string& filename,
         moduleInCMakeModulePath = itempl;
         break;
       }
+      if (debug) {
+        debugBuffer = cmStrCat(debugBuffer, "  ", itempl, "\n");
+      }
     }
   }
 
@@ -3767,6 +3771,9 @@ std::string cmMakefile::GetModulesFile(const std::string& filename,
     cmStrCat(cmSystemTools::GetCMakeRoot(), "/Modules/", filename);
   cmSystemTools::ConvertToUnixSlashes(moduleInCMakeRoot);
   if (!cmSystemTools::FileExists(moduleInCMakeRoot)) {
+    if (debug) {
+      debugBuffer = cmStrCat(debugBuffer, "  ", moduleInCMakeRoot, "\n");
+    }
     moduleInCMakeRoot.clear();
   }