Merge topic 'cps-link-only'

ebe487ea81 export: Allow export with LINK_ONLY library dependencies
13c7bb5b0c cmGeneratorExpression: Update strip function to collect parsed expressions

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !10522

Source/cmExportPackageInfoGenerator.cxx

@@ -2,6 +2,7 @@
    file LICENSE.rst or https://cmake.org/licensing for details.  */
 #include "cmExportPackageInfoGenerator.h"
 
+#include <cstddef>
 #include <memory>
 #include <set>
 #include <utility>
@@ -210,13 +211,15 @@ bool cmExportPackageInfoGenerator::GenerateInterfaceProperties(
 }
 
 namespace {
-bool forbidGeneratorExpressions(std::string const& propertyName,
-                                std::string const& propertyValue,
-                                cmGeneratorTarget const* target)
+bool ForbidGeneratorExpressions(
+  cmGeneratorTarget const* target, std::string const& propertyName,
+  std::string const& propertyValue, std::string& evaluatedValue,
+  std::map<std::string, std::vector<std::string>>& allowList)
 {
-  std::string const& evaluatedValue = cmGeneratorExpression::Preprocess(
-    propertyValue, cmGeneratorExpression::StripAllGeneratorExpressions);
-  if (evaluatedValue != propertyValue) {
+  size_t const allowedExpressions = allowList.size();
+  evaluatedValue = cmGeneratorExpression::Collect(propertyValue, allowList);
+  if (evaluatedValue != propertyValue &&
+      allowList.size() > allowedExpressions) {
     target->Makefile->IssueMessage(
       MessageType::FATAL_ERROR,
       cmStrCat("Property \"", propertyName, "\" of target \"",
@@ -224,8 +227,32 @@ bool forbidGeneratorExpressions(std::string const& propertyName,
                "\" contains a generator expression. This is not allowed."));
     return false;
   }
+  // Forbid Nested Generator Expressions
+  for (auto const& genexp : allowList) {
+    for (auto const& value : genexp.second) {
+      if (value.find("$<") != std::string::npos) {
+        target->Makefile->IssueMessage(
+          MessageType::FATAL_ERROR,
+          cmStrCat(
+            "$<", genexp.first, ":...> expression in \"", propertyName,
+            "\" of target \"", target->GetName(),
+            "\" contains a generator expression. This is not allowed."));
+        return false;
+      }
+    }
+  }
   return true;
 }
+
+bool ForbidGeneratorExpressions(cmGeneratorTarget const* target,
+                                std::string const& propertyName,
+                                std::string const& propertyValue)
+{
+  std::map<std::string, std::vector<std::string>> allowList;
+  std::string evaluatedValue;
+  return ForbidGeneratorExpressions(target, propertyName, propertyValue,
+                                    evaluatedValue, allowList);
+}
 }
 
 bool cmExportPackageInfoGenerator::NoteLinkedTarget(
@@ -317,31 +344,43 @@ void cmExportPackageInfoGenerator::GenerateInterfaceLinkProperties(
     return;
   }
 
-  // TODO: Support $<LINK_ONLY>.
-  if (!forbidGeneratorExpressions(iter->first, iter->second, target)) {
+  // Extract any $<LINK_ONLY:...> from the link libraries, and assert that no
+  // other generator expressions are present.
+  std::map<std::string, std::vector<std::string>> allowList = { { "LINK_ONLY",
+                                                                  {} } };
+  std::string interfaceLinkLibraries;
+  if (!ForbidGeneratorExpressions(target, iter->first, iter->second,
+                                  interfaceLinkLibraries, allowList)) {
     result = false;
     return;
   }
 
-  std::vector<std::string> buildRequires;
-  // std::vector<std::string> linkRequires; TODO
   std::vector<std::string> linkLibraries;
+  std::vector<std::string> linkRequires;
+  std::vector<std::string> buildRequires;
 
-  for (auto const& name : cmList{ iter->second }) {
-    auto const& ti = this->LinkTargets.find(name);
-    if (ti != this->LinkTargets.end()) {
-      if (ti->second.empty()) {
-        result = false;
+  auto addLibraries = [this, &linkLibraries,
+                       &result](std::vector<std::string> const& names,
+                                std::vector<std::string>& output) -> void {
+    for (auto const& name : names) {
+      auto const& ti = this->LinkTargets.find(name);
+      if (ti != this->LinkTargets.end()) {
+        if (ti->second.empty()) {
+          result = false;
+        } else {
+          output.emplace_back(ti->second);
+        }
       } else {
-        buildRequires.emplace_back(ti->second);
+        linkLibraries.emplace_back(name);
       }
-    } else {
-      linkLibraries.emplace_back(name);
     }
-  }
+  };
+
+  addLibraries(allowList["LINK_ONLY"], linkRequires);
+  addLibraries(cmList{ interfaceLinkLibraries }, buildRequires);
 
   buildArray(component, "requires", buildRequires);
-  // buildArray(component, "link_requires", linkRequires); TODO
+  buildArray(component, "link_requires", linkRequires);
   buildArray(component, "link_libraries", linkLibraries);
 }
 
@@ -354,7 +393,7 @@ void cmExportPackageInfoGenerator::GenerateInterfaceCompileFeatures(
     return;
   }
 
-  if (!forbidGeneratorExpressions(iter->first, iter->second, target)) {
+  if (!ForbidGeneratorExpressions(target, iter->first, iter->second)) {
     result = false;
     return;
   }
@@ -383,7 +422,7 @@ void cmExportPackageInfoGenerator::GenerateInterfaceCompileDefines(
   }
 
   // TODO: Support language-specific defines.
-  if (!forbidGeneratorExpressions(iter->first, iter->second, target)) {
+  if (!ForbidGeneratorExpressions(target, iter->first, iter->second)) {
     result = false;
     return;
   }
@@ -414,7 +453,7 @@ void cmExportPackageInfoGenerator::GenerateInterfaceListProperty(
     return;
   }
 
-  if (!forbidGeneratorExpressions(prop, iter->second, target)) {
+  if (!ForbidGeneratorExpressions(target, prop, iter->second)) {
     result = false;
     return;
   }

Source/cmGeneratorExpression.cxx

@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <cassert>
 #include <memory>
+#include <stack>
 #include <utility>
 
 #include <cm/string_view>
@@ -156,27 +157,40 @@ std::string cmGeneratorExpression::StripEmptyListElements(
   return result;
 }
 
-static std::string stripAllGeneratorExpressions(std::string const& input)
+static std::string extractAllGeneratorExpressions(
+  std::string const& input,
+  std::map<std::string, std::vector<std::string>>* collected)
 {
   std::string result;
   std::string::size_type pos = 0;
   std::string::size_type lastPos = pos;
-  int nestingLevel = 0;
+  // stack of { Generator Expression Name, Start Position of Value }
+  std::stack<std::pair<std::string, std::string::size_type>> genexps;
   while ((pos = input.find("$<", lastPos)) != std::string::npos) {
     result += input.substr(lastPos, pos - lastPos);
     pos += 2;
-    nestingLevel = 1;
     char const* c = input.c_str() + pos;
+    char const* cName = c;
     char const* const cStart = c;
     for (; *c; ++c) {
       if (cmGeneratorExpression::StartsWithGeneratorExpression(c)) {
-        ++nestingLevel;
         ++c;
+        cName = c + 1;
         continue;
       }
-      if (c[0] == '>') {
-        --nestingLevel;
-        if (nestingLevel == 0) {
+      if (c[0] == ':' && cName) {
+        genexps.push({ input.substr(pos + (cName - cStart), c - cName),
+                       pos + (c + 1 - cStart) });
+        cName = nullptr;
+      } else if (c[0] == '>') {
+        if (!cName && !genexps.empty()) {
+          if (collected) {
+            (*collected)[genexps.top().first].push_back(input.substr(
+              genexps.top().second, pos + c - cStart - genexps.top().second));
+          }
+          genexps.pop();
+        }
+        if (genexps.empty()) {
           break;
         }
       }
@@ -188,12 +202,17 @@ static std::string stripAllGeneratorExpressions(std::string const& input)
     pos += traversed;
     lastPos = pos;
   }
-  if (nestingLevel == 0) {
+  if (genexps.empty()) {
     result += input.substr(lastPos);
   }
   return cmGeneratorExpression::StripEmptyListElements(result);
 }
 
+static std::string stripAllGeneratorExpressions(std::string const& input)
+{
+  return extractAllGeneratorExpressions(input, nullptr);
+}
+
 static void prefixItems(std::string const& content, std::string& result,
                         cm::string_view const& prefix)
 {
@@ -375,6 +394,13 @@ std::string cmGeneratorExpression::Preprocess(std::string const& input,
   return std::string();
 }
 
+std::string cmGeneratorExpression::Collect(
+  std::string const& input,
+  std::map<std::string, std::vector<std::string>>& collected)
+{
+  return extractAllGeneratorExpressions(input, &collected);
+}
+
 cm::string_view::size_type cmGeneratorExpression::Find(
   cm::string_view const& input)
 {

Source/cmGeneratorExpression.h

@@ -63,6 +63,10 @@ public:
                                 PreprocessContext context,
                                 cm::string_view importPrefix = {});
 
+  static std::string Collect(
+    std::string const& input,
+    std::map<std::string, std::vector<std::string>>& collected);
+
   static void Split(std::string const& input,
                     std::vector<std::string>& output);