Makefile: Fix rebuild with multiple custom command outputs (#15116)

Fix the generated makefiles for custom commands with multiple outputs to
list all the outputs on the left hand side of the build rule.  This is
much simpler and more reliable than the old multiple-output-pair
infrastructure.

1 files changed, 43 insertions, 3 deletions

diff --git a/Source/cmLocalUnixMakefileGenerator3.cxx b/Source/cmLocalUnixMakefileGenerator3.cxx
index ff8ba8b..56b2b97 100644
--- a/Source/cmLocalUnixMakefileGenerator3.cxx
+++ b/Source/cmLocalUnixMakefileGenerator3.cxx
@@ -618,6 +618,30 @@ cmLocalUnixMakefileGenerator3
                          comment);
     return;
     }
+  std::vector<std::string> outputs(1, target);
+  this->WriteMakeRule(os, comment,
+                      outputs, depends, commands,
+                      symbolic, in_help);
+}
+
+//----------------------------------------------------------------------------
+void
+cmLocalUnixMakefileGenerator3
+::WriteMakeRule(std::ostream& os,
+                const char* comment,
+                const std::vector<std::string>& outputs,
+                const std::vector<std::string>& depends,
+                const std::vector<std::string>& commands,
+                bool symbolic,
+                bool in_help)
+{
+  // Make sure there is an output.
+  if(outputs.empty())
+    {
+    cmSystemTools::Error("No outputs for WriteMakeRule! called with comment: ",
+                         comment);
+    return;
+    }
 
   std::string replace;
 
@@ -636,8 +660,18 @@ cmLocalUnixMakefileGenerator3
     }
 
   // Construct the left hand side of the rule.
-  replace = target;
-  std::string tgt = this->Convert(replace,HOME_OUTPUT,MAKERULE);
+  std::string tgt;
+  {
+  const char* sep = "";
+  for (std::vector<std::string>::const_iterator i = outputs.begin();
+       i != outputs.end(); ++i)
+    {
+    tgt += sep;
+    tgt += this->Convert(*i,HOME_OUTPUT,MAKERULE);
+    sep = " ";
+    }
+  }
+
   const char* space = "";
   if(tgt.size() == 1)
     {
@@ -690,7 +724,11 @@ cmLocalUnixMakefileGenerator3
   // Add the output to the local help if requested.
   if(in_help)
     {
-    this->LocalHelp.push_back(target);
+    for (std::vector<std::string>::const_iterator i = outputs.begin();
+         i != outputs.end(); ++i)
+      {
+      this->LocalHelp.push_back(*i);
+      }
     }
 }
 
@@ -1709,6 +1747,8 @@ cmLocalUnixMakefileGenerator3
 //----------------------------------------------------------------------------
 void cmLocalUnixMakefileGenerator3::CheckMultipleOutputs(bool verbose)
 {
+  // Nothing populates multiple output pairs anymore, but we need to
+  // honor it when working in a build tree generated by an older CMake.
   cmMakefile* mf = this->Makefile;
 
   // Get the string listing the multiple output pairs.