cmMakefile: Add lookup from source name to targets via byproducts

Given an output source name it is now possible to query which target has a
byproduct of this name or has a PRE_BUILD, PRE_LINK, or POST_BUILD build event
with a byproduct of this name.

In a call to GetSourceFileWithOutput a matching byproduct can now optionally be
returned as fallback if there is no matching output of a custom command.

Default behavior is not changed by this commit.

Source/cmMakefile.cxx

@@ -908,6 +908,37 @@ void cmMakefile::AddCustomCommandToTarget(
       t.AddPostBuildCommand(cc);
       break;
   }
+  this->UpdateOutputToSourceMap(byproducts, &t);
+}
+
+void cmMakefile::UpdateOutputToSourceMap(
+  std::vector<std::string> const& byproducts, cmTarget* target)
+{
+  for (std::string const& o : byproducts) {
+    this->UpdateOutputToSourceMap(o, target);
+  }
+}
+
+void cmMakefile::UpdateOutputToSourceMap(std::string const& byproduct,
+                                         cmTarget* target)
+{
+  SourceEntry entry;
+  entry.Sources.Target = target;
+
+  auto pr = this->OutputToSource.emplace(byproduct, entry);
+  if (!pr.second) {
+    SourceEntry& current = pr.first->second;
+    // Has the target already been set?
+    if (!current.Sources.Target) {
+      current.Sources.Target = target;
+    } else {
+      // Multiple custom commands/targets produce the same output (source file
+      // or target).  See also comment in other UpdateOutputToSourceMap
+      // overload.
+      //
+      // TODO: Warn the user about this case.
+    }
+  }
 }
 
 cmSourceFile* cmMakefile::AddCustomCommandToOutput(
@@ -1003,35 +1034,47 @@ cmSourceFile* cmMakefile::AddCustomCommandToOutput(
     cc->SetDepfile(depfile);
     cc->SetJobPool(job_pool);
     file->SetCustomCommand(cc);
-    this->UpdateOutputToSourceMap(outputs, file);
+    this->UpdateOutputToSourceMap(outputs, file, false);
+    this->UpdateOutputToSourceMap(byproducts, file, true);
   }
   return file;
 }
 
 void cmMakefile::UpdateOutputToSourceMap(
-  std::vector<std::string> const& outputs, cmSourceFile* source)
+  std::vector<std::string> const& outputs, cmSourceFile* source,
+  bool byproduct)
 {
   for (std::string const& o : outputs) {
-    this->UpdateOutputToSourceMap(o, source);
+    this->UpdateOutputToSourceMap(o, source, byproduct);
   }
 }
 
 void cmMakefile::UpdateOutputToSourceMap(std::string const& output,
-                                         cmSourceFile* source)
+                                         cmSourceFile* source, bool byproduct)
 {
-  auto i = this->OutputToSource.find(output);
-  if (i != this->OutputToSource.end()) {
-    // Multiple custom commands produce the same output but may
-    // be attached to a different source file (MAIN_DEPENDENCY).
-    // LinearGetSourceFileWithOutput would return the first one,
-    // so keep the mapping for the first one.
-    //
-    // TODO: Warn the user about this case.  However, the VS 8 generator
-    // triggers it for separate generate.stamp rules in ZERO_CHECK and
-    // individual targets.
-    return;
+  SourceEntry entry;
+  entry.Sources.Source = source;
+  entry.Sources.SourceIsByproduct = byproduct;
+
+  auto pr = this->OutputToSource.emplace(output, entry);
+  if (!pr.second) {
+    SourceEntry& current = pr.first->second;
+    // Outputs take precedence over byproducts
+    if (!current.Sources.Source ||
+        (current.Sources.SourceIsByproduct && !byproduct)) {
+      current.Sources.Source = source;
+      current.Sources.SourceIsByproduct = false;
+    } else {
+      // Multiple custom commands produce the same output but may
+      // be attached to a different source file (MAIN_DEPENDENCY).
+      // LinearGetSourceFileWithOutput would return the first one,
+      // so keep the mapping for the first one.
+      //
+      // TODO: Warn the user about this case.  However, the VS 8 generator
+      // triggers it for separate generate.stamp rules in ZERO_CHECK and
+      // individual targets.
+    }
   }
-  this->OutputToSource[output] = source;
 }
 
 cmSourceFile* cmMakefile::AddCustomCommandToOutput(
@@ -1194,6 +1237,8 @@ cmTarget* cmMakefile::AddUtilityCommand(
     } else {
       cmSystemTools::Error("Could not get source file entry for " + force);
     }
+
+    this->UpdateOutputToSourceMap(byproducts, target);
   }
   return target;
 }
@@ -2007,6 +2052,7 @@ cmTarget* cmMakefile::AddNewTarget(cmStateEnums::TargetType type,
     this->Targets
       .emplace(name, cmTarget(name, type, cmTarget::VisibilityNormal, this))
       .first;
+  this->OrderedTargets.push_back(&it->second);
   this->GetGlobalGenerator()->IndexTarget(&it->second);
   this->GetStateSnapshot().GetDirectory().AddNormalTargetName(name);
   return &it->second;
@@ -2026,11 +2072,45 @@ bool AnyOutputMatches(const std::string& name,
   }
   return false;
 }
+
+bool AnyTargetCommandOutputMatches(
+  const std::string& name, const std::vector<cmCustomCommand>& commands)
+{
+  for (cmCustomCommand const& command : commands) {
+    if (AnyOutputMatches(name, command.GetByproducts())) {
+      return true;
+    }
+  }
+  return false;
+}
+}
+
+cmTarget* cmMakefile::LinearGetTargetWithOutput(const std::string& name) const
+{
+  // We go through the ordered vector of targets to get reproducible results
+  // should multiple names match.
+  for (cmTarget* t : this->OrderedTargets) {
+    // Does the output of any command match the source file name?
+    if (AnyTargetCommandOutputMatches(name, t->GetPreBuildCommands())) {
+      return t;
+    }
+    if (AnyTargetCommandOutputMatches(name, t->GetPreLinkCommands())) {
+      return t;
+    }
+    if (AnyTargetCommandOutputMatches(name, t->GetPostBuildCommands())) {
+      return t;
+    }
+  }
+  return nullptr;
 }
 
 cmSourceFile* cmMakefile::LinearGetSourceFileWithOutput(
-  const std::string& name) const
+  const std::string& name, cmSourceOutputKind kind, bool& byproduct) const
 {
+  // Outputs take precedence over byproducts.
+  byproduct = false;
+  cmSourceFile* fallback = nullptr;
+
   // Look through all the source files that have custom commands and see if the
   // custom command has the passed source file as an output.
   for (cmSourceFile* src : this->SourceFiles) {
@@ -2041,25 +2121,57 @@ cmSourceFile* cmMakefile::LinearGetSourceFileWithOutput(
         // Return the first matching output.
         return src;
       }
+      if (kind == cmSourceOutputKind::OutputOrByproduct) {
+        if (AnyOutputMatches(name, src->GetCustomCommand()->GetByproducts())) {
+          // Do not return the source yet as there might be a matching output.
+          fallback = src;
+        }
+      }
     }
   }
 
-  // otherwise return NULL
-  return nullptr;
+  // Did we find a byproduct?
+  byproduct = fallback != nullptr;
+  return fallback;
 }
 
-cmSourceFile* cmMakefile::GetSourceFileWithOutput(
+cmSourcesWithOutput cmMakefile::GetSourcesWithOutput(
   const std::string& name) const
 {
-  // If the queried path is not absolute we use the backward compatible
-  // linear-time search for an output with a matching suffix.
+  // Linear search?  Also see GetSourceFileWithOutput for detail.
   if (!cmSystemTools::FileIsFullPath(name)) {
-    return this->LinearGetSourceFileWithOutput(name);
+    cmSourcesWithOutput sources;
+    sources.Target = this->LinearGetTargetWithOutput(name);
+    sources.Source = this->LinearGetSourceFileWithOutput(
+      name, cmSourceOutputKind::OutputOrByproduct, sources.SourceIsByproduct);
+    return sources;
   }
   // Otherwise we use an efficient lookup map.
   auto o = this->OutputToSource.find(name);
   if (o != this->OutputToSource.end()) {
-    return (*o).second;
+    return o->second.Sources;
+  }
+  return {};
+}
+
+cmSourceFile* cmMakefile::GetSourceFileWithOutput(
+  const std::string& name, cmSourceOutputKind kind) const
+{
+  // If the queried path is not absolute we use the backward compatible
+  // linear-time search for an output with a matching suffix.
+  if (!cmSystemTools::FileIsFullPath(name)) {
+    bool byproduct = false;
+    return this->LinearGetSourceFileWithOutput(name, kind, byproduct);
+  }
+  // Otherwise we use an efficient lookup map.
+  auto o = this->OutputToSource.find(name);
+  if (o != this->OutputToSource.end() &&
+      (!o->second.Sources.SourceIsByproduct ||
+       kind == cmSourceOutputKind::OutputOrByproduct)) {
+    // Source file could also be null pointer for example if we found the
+    // byproduct of a utility target or a PRE_BUILD, PRE_LINK, or POST_BUILD
+    // command of a target.
+    return o->second.Sources.Source;
   }
   return nullptr;
 }

Source/cmMakefile.h

@@ -51,6 +51,24 @@ class cmTestGenerator;
 class cmVariableWatch;
 class cmake;
 
+/** Flag if byproducts shall also be considered.  */
+enum class cmSourceOutputKind
+{
+  OutputOnly,
+  OutputOrByproduct
+};
+
+/** Target and source file which have a specific output.  */
+struct cmSourcesWithOutput
+{
+  /** Target with byproduct.  */
+  cmTarget* Target = nullptr;
+
+  /** Source file with output or byproduct.  */
+  cmSourceFile* Source = nullptr;
+  bool SourceIsByproduct = false;
+};
+
 /** A type-safe wrapper for a string representing a directory id.  */
 class cmDirectoryId
 {
@@ -687,10 +705,19 @@ public:
   }
 
   /**
-   * Is there a source file that has the provided source file as an output?
-   * if so then return it
+   * Return the target if the provided source name is a byproduct of a utility
+   * target or a PRE_BUILD, PRE_LINK, or POST_BUILD command.
+   * Return the source file which has the provided source name as output.
    */
-  cmSourceFile* GetSourceFileWithOutput(const std::string& outName) const;
+  cmSourcesWithOutput GetSourcesWithOutput(const std::string& name) const;
+
+  /**
+   * Is there a source file that has the provided source name as an output?
+   * If so then return it.
+   */
+  cmSourceFile* GetSourceFileWithOutput(
+    const std::string& name,
+    cmSourceOutputKind kind = cmSourceOutputKind::OutputOnly) const;
 
   //! Add a new cmTest to the list of tests for this makefile.
   cmTest* CreateTest(const std::string& testName);
@@ -914,6 +941,9 @@ protected:
   mutable cmTargetMap Targets;
   std::map<std::string, std::string> AliasTargets;
 
+  using TargetsVec = std::vector<cmTarget*>;
+  TargetsVec OrderedTargets;
+
   using SourceFileVec = std::vector<cmSourceFile*>;
   SourceFileVec SourceFiles;
 
@@ -1036,21 +1066,37 @@ private:
     cmSourceFileLocationKind kind = cmSourceFileLocationKind::Ambiguous);
 
   /**
-   * Old version of GetSourceFileWithOutput(const std::string&) kept for
-   * backward-compatibility. It implements a linear search and support
-   * relative file paths. It is used as a fall back by
-   * GetSourceFileWithOutput(const std::string&).
+   * See LinearGetSourceFileWithOutput for background information
    */
-  cmSourceFile* LinearGetSourceFileWithOutput(const std::string& cname) const;
+  cmTarget* LinearGetTargetWithOutput(const std::string& name) const;
+
+  /**
+   * Generalized old version of GetSourceFileWithOutput kept for
+   * backward-compatibility. It implements a linear search and supports
+   * relative file paths. It is used as a fall back by GetSourceFileWithOutput
+   * and GetSourcesWithOutput.
+   */
+  cmSourceFile* LinearGetSourceFileWithOutput(const std::string& name,
+                                              cmSourceOutputKind kind,
+                                              bool& byproduct) const;
+
+  struct SourceEntry
+  {
+    cmSourcesWithOutput Sources;
+  };
 
   // A map for fast output to input look up.
-  using OutputToSourceMap = std::unordered_map<std::string, cmSourceFile*>;
+  using OutputToSourceMap = std::unordered_map<std::string, SourceEntry>;
   OutputToSourceMap OutputToSource;
 
+  void UpdateOutputToSourceMap(std::vector<std::string> const& byproducts,
+                               cmTarget* target);
+  void UpdateOutputToSourceMap(std::string const& byproduct, cmTarget* target);
+
   void UpdateOutputToSourceMap(std::vector<std::string> const& outputs,
-                               cmSourceFile* source);
-  void UpdateOutputToSourceMap(std::string const& output,
-                               cmSourceFile* source);
+                               cmSourceFile* source, bool byproduct);
+  void UpdateOutputToSourceMap(std::string const& output, cmSourceFile* source,
+                               bool byproduct);
 
   bool AddRequiredTargetCFeature(cmTarget* target, const std::string& feature,
                                  std::string* error = nullptr) const;