Genex: Add generator expressions $<DEVICE_LINK> and $<HOST_LINK>

These generator expressions can only be used in link options properties.
These expressions return the arguments respectively for device and host link
step, otherwise return an empty string.

Source/cmGeneratorExpressionDAGChecker.cxx

@@ -163,6 +163,13 @@ bool cmGeneratorExpressionDAGChecker::EvaluatingLinkExpression() const
     property == "LINK_DEPENDS"_s;
 }
 
+bool cmGeneratorExpressionDAGChecker::EvaluatingLinkOptionsExpression() const
+{
+  cm::string_view property(this->Top()->Property);
+
+  return property == "LINK_OPTIONS"_s;
+}
+
 bool cmGeneratorExpressionDAGChecker::EvaluatingLinkLibraries(
   cmGeneratorTarget const* tgt) const
 {

Source/cmGeneratorExpressionDAGChecker.h

@@ -69,6 +69,7 @@ struct cmGeneratorExpressionDAGChecker
   bool EvaluatingGenexExpression() const;
   bool EvaluatingPICExpression() const;
   bool EvaluatingLinkExpression() const;
+  bool EvaluatingLinkOptionsExpression() const;
 
   bool EvaluatingLinkLibraries(cmGeneratorTarget const* tgt = nullptr) const;
 

Source/cmGeneratorExpressionNode.cxx

@@ -15,6 +15,7 @@
 
 #include <cm/iterator>
 #include <cm/string_view>
+#include <cm/vector>
 #include <cmext/algorithm>
 
 #include "cmsys/RegularExpression.hxx"
@@ -1187,6 +1188,70 @@ static const struct LinkLanguageAndIdNode : public cmGeneratorExpressionNode
   }
 } linkLanguageAndIdNode;
 
+static const struct HostLinkNode : public cmGeneratorExpressionNode
+{
+  HostLinkNode() {} // NOLINT(modernize-use-equals-default)
+
+  int NumExpectedParameters() const override { return ZeroOrMoreParameters; }
+
+  std::string Evaluate(
+    const std::vector<std::string>& parameters,
+    cmGeneratorExpressionContext* context,
+    const GeneratorExpressionContent* content,
+    cmGeneratorExpressionDAGChecker* dagChecker) const override
+  {
+    if (!context->HeadTarget || !dagChecker ||
+        !dagChecker->EvaluatingLinkOptionsExpression()) {
+      reportError(context, content->GetOriginalExpression(),
+                  "$<HOST_LINK:...> may only be used with binary targets "
+                  "to specify link options.");
+      return std::string();
+    }
+
+    return context->HeadTarget->IsDeviceLink() ? std::string()
+                                               : cmJoin(parameters, ";");
+  }
+} hostLinkNode;
+
+static const struct DeviceLinkNode : public cmGeneratorExpressionNode
+{
+  DeviceLinkNode() {} // NOLINT(modernize-use-equals-default)
+
+  int NumExpectedParameters() const override { return ZeroOrMoreParameters; }
+
+  std::string Evaluate(
+    const std::vector<std::string>& parameters,
+    cmGeneratorExpressionContext* context,
+    const GeneratorExpressionContent* content,
+    cmGeneratorExpressionDAGChecker* dagChecker) const override
+  {
+    if (!context->HeadTarget || !dagChecker ||
+        !dagChecker->EvaluatingLinkOptionsExpression()) {
+      reportError(context, content->GetOriginalExpression(),
+                  "$<DEVICE_LINK:...> may only be used with binary targets "
+                  "to specify link options.");
+      return std::string();
+    }
+
+    if (context->HeadTarget->IsDeviceLink()) {
+      std::vector<std::string> list;
+      cmExpandLists(parameters.begin(), parameters.end(), list);
+      const auto DL_BEGIN = "<DEVICE_LINK>"_s;
+      const auto DL_END = "</DEVICE_LINK>"_s;
+      cm::erase_if(list, [&](const std::string& item) {
+        return item == DL_BEGIN || item == DL_END;
+      });
+
+      list.insert(list.begin(), static_cast<std::string>(DL_BEGIN));
+      list.push_back(static_cast<std::string>(DL_END));
+
+      return cmJoin(list, ";");
+    }
+
+    return std::string();
+  }
+} deviceLinkNode;
+
 std::string getLinkedTargetsContent(
   cmGeneratorTarget const* target, std::string const& prop,
   cmGeneratorExpressionContext* context,
@@ -1304,6 +1369,7 @@ static const struct TargetPropertyNode : public cmGeneratorExpressionNode
           context, content->GetOriginalExpression(),
           "$<TARGET_PROPERTY:prop>  may only be used with binary targets.  "
           "It may not be used with add_custom_command or add_custom_target.  "
+          " "
           "Specify the target to read a property from using the "
           "$<TARGET_PROPERTY:tgt,prop> signature instead.");
         return std::string();
@@ -2464,6 +2530,8 @@ const cmGeneratorExpressionNode* cmGeneratorExpressionNode::GetNode(
     { "COMPILE_LANGUAGE", &languageNode },
     { "LINK_LANG_AND_ID", &linkLanguageAndIdNode },
     { "LINK_LANGUAGE", &linkLanguageNode },
+    { "HOST_LINK", &hostLinkNode },
+    { "DEVICE_LINK", &deviceLinkNode },
     { "SHELL_PATH", &shellPathNode }
   };
 

Source/cmGeneratorTarget.cxx

@@ -5532,6 +5532,13 @@ PropertyType checkInterfacePropertyCompatibility(cmGeneratorTarget const* tgt,
   return propContent;
 }
 
+bool cmGeneratorTarget::SetDeviceLink(bool deviceLink)
+{
+  bool previous = this->DeviceLink;
+  this->DeviceLink = deviceLink;
+  return previous;
+}
+
 bool cmGeneratorTarget::GetLinkInterfaceDependentBoolProperty(
   const std::string& p, const std::string& config) const
 {
@@ -5955,7 +5962,6 @@ const cmLinkInterfaceLibraries* cmGeneratorTarget::GetLinkInterfaceLibraries(
   }
 
   // Lookup any existing link interface for this configuration.
-  std::string CONFIG = cmSystemTools::UpperCase(config);
   cmHeadToLinkInterfaceMap& hm =
     (usage_requirements_only
        ? this->GetHeadToLinkInterfaceUsageRequirementsMap(config)
@@ -6377,7 +6383,6 @@ const cmLinkInterface* cmGeneratorTarget::GetImportLinkInterface(
     return nullptr;
   }
 
-  std::string CONFIG = cmSystemTools::UpperCase(config);
   cmHeadToLinkInterfaceMap& hm =
     (usage_requirements_only
        ? this->GetHeadToLinkInterfaceUsageRequirementsMap(config)
@@ -6591,16 +6596,15 @@ void cmGeneratorTarget::ComputeImportInfo(std::string const& desired_config,
 cmHeadToLinkInterfaceMap& cmGeneratorTarget::GetHeadToLinkInterfaceMap(
   const std::string& config) const
 {
-  std::string CONFIG = cmSystemTools::UpperCase(config);
-  return this->LinkInterfaceMap[CONFIG];
+  return this->LinkInterfaceMap[cmSystemTools::UpperCase(config)];
 }
 
 cmHeadToLinkInterfaceMap&
 cmGeneratorTarget::GetHeadToLinkInterfaceUsageRequirementsMap(
   const std::string& config) const
 {
-  std::string CONFIG = cmSystemTools::UpperCase(config);
-  return this->LinkInterfaceUsageRequirementsOnlyMap[CONFIG];
+  return this
+    ->LinkInterfaceUsageRequirementsOnlyMap[cmSystemTools::UpperCase(config)];
 }
 
 const cmLinkImplementation* cmGeneratorTarget::GetLinkImplementation(
@@ -6617,8 +6621,8 @@ const cmLinkImplementation* cmGeneratorTarget::GetLinkImplementation(
     return nullptr;
   }
 
-  std::string CONFIG = cmSystemTools::UpperCase(config);
-  cmOptionalLinkImplementation& impl = this->LinkImplMap[CONFIG][this];
+  cmOptionalLinkImplementation& impl =
+    this->LinkImplMap[cmSystemTools::UpperCase(config)][this];
   if (secondPass) {
     impl = cmOptionalLinkImplementation();
   }
@@ -6877,8 +6881,8 @@ cmGeneratorTarget::GetLinkImplementationLibrariesInternal(
   }
 
   // Populate the link implementation libraries for this configuration.
-  std::string CONFIG = cmSystemTools::UpperCase(config);
-  HeadToLinkImplementationMap& hm = this->LinkImplMap[CONFIG];
+  HeadToLinkImplementationMap& hm =
+    this->LinkImplMap[cmSystemTools::UpperCase(config)];
 
   // If the link implementation does not depend on the head target
   // then return the one we computed first.

Source/cmGeneratorTarget.h

@@ -204,6 +204,24 @@ public:
   const char* GetLinkInterfaceDependentNumberMaxProperty(
     const std::string& p, const std::string& config) const;
 
+  class DeviceLinkSetter
+  {
+  public:
+    DeviceLinkSetter(cmGeneratorTarget& target)
+      : Target(target)
+    {
+      this->PreviousState = target.SetDeviceLink(true);
+    }
+    ~DeviceLinkSetter() { this->Target.SetDeviceLink(this->PreviousState); };
+
+  private:
+    cmGeneratorTarget& Target;
+    bool PreviousState;
+  };
+
+  bool SetDeviceLink(bool deviceLink);
+  bool IsDeviceLink() const { return this->DeviceLink; }
+
   cmLinkInterface const* GetLinkInterface(
     const std::string& config, const cmGeneratorTarget* headTarget) const;
   void ComputeLinkInterface(const std::string& config,
@@ -829,6 +847,7 @@ private:
   mutable std::string LinkerLanguage;
   using LinkClosureMapType = std::map<std::string, LinkClosure>;
   mutable LinkClosureMapType LinkClosureMap;
+  bool DeviceLink = false;
 
   // Returns ARCHIVE, LIBRARY, or RUNTIME based on platform and type.
   const char* GetOutputTargetType(cmStateEnums::ArtifactType artifact) const;

Source/cmStringAlgorithms.h

@@ -87,7 +87,7 @@ void cmExpandLists(InputIt first, InputIt last,
                    std::vector<std::string>& argsOut)
 {
   for (; first != last; ++first) {
-    ExpandList(*first, argsOut);
+    cmExpandList(*first, argsOut);
   }
 }