Add generator expression support to PDB_OUTPUT_DIRECTORY target property

Fixes: #16365

Help/prop_tgt/PDB_OUTPUT_DIRECTORY.rst

@@ -5,8 +5,14 @@ Output directory for the MS debug symbols ``.pdb`` file
 generated by the linker for an executable or shared library target.
 
 This property specifies the directory into which the MS debug symbols
-will be placed by the linker.  This property is initialized by the
-value of the :variable:`CMAKE_PDB_OUTPUT_DIRECTORY` variable if it is
+will be placed by the linker. The property value may use
+:manual:`generator expressions <cmake-generator-expressions(7)>`.
+Multi-configuration generators append a per-configuration
+subdirectory to the specified directory unless a generator expression
+is used.
+
+This property is initialized by the value of the
+:variable:`CMAKE_PDB_OUTPUT_DIRECTORY` variable if it is
 set when a target is created.
 
 .. |COMPILE_PDB_XXX| replace:: :prop_tgt:`COMPILE_PDB_OUTPUT_DIRECTORY`

Help/prop_tgt/PDB_OUTPUT_DIRECTORY_CONFIG.rst

@@ -11,5 +11,8 @@ property is initialized by the value of the
 :variable:`CMAKE_PDB_OUTPUT_DIRECTORY_<CONFIG>` variable if it is
 set when a target is created.
 
+Contents of ``PDB_OUTPUT_DIRECTORY_<CONFIG>`` may use
+:manual:`generator expressions <cmake-generator-expressions(7)>`.
+
 .. |COMPILE_PDB_XXX| replace:: :prop_tgt:`COMPILE_PDB_OUTPUT_DIRECTORY_<CONFIG>`
 .. include:: PDB_NOTE.txt

Help/release/dev/PDBDirectoryGenExpression.rst

@@ -0,0 +1,5 @@
+PDBDirectoryGenExpression
+-------------------------
+
+* The :prop_tgt:`PDB_OUTPUT_DIRECTORY` property learned to support
+  :manual:`generator expressions <cmake-generator-expressions(7)>`.

Source/cmGeneratorTarget.cxx

@@ -4612,13 +4612,24 @@ bool cmGeneratorTarget::ComputePDBOutputDir(const std::string& kind,
   // Select an output directory.
   if (const char* config_outdir = this->GetProperty(configProp)) {
     // Use the user-specified per-configuration output directory.
-    out = config_outdir;
+    cmGeneratorExpression ge;
+    std::unique_ptr<cmCompiledGeneratorExpression> cge =
+      ge.Parse(config_outdir);
+    out = cge->Evaluate(this->LocalGenerator, config);
 
     // Skip per-configuration subdirectory.
     conf.clear();
   } else if (const char* outdir = this->GetProperty(propertyName)) {
     // Use the user-specified output directory.
-    out = outdir;
+    cmGeneratorExpression ge;
+    std::unique_ptr<cmCompiledGeneratorExpression> cge = ge.Parse(outdir);
+    out = cge->Evaluate(this->LocalGenerator, config);
+
+    // Skip per-configuration subdirectory if the value contained a
+    // generator expression.
+    if (out != outdir) {
+      conf.clear();
+    }
   }
   if (out.empty()) {
     return false;

Tests/PDBDirectoryAndName/CMakeLists.txt

@@ -19,7 +19,7 @@ set(my_targets "")
 add_library(mylibA SHARED mylibA.c)
 set_target_properties(mylibA PROPERTIES
     PDB_NAME "mylibA_Special"
-    PDB_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/mylibA_PDB"
+    PDB_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/mylibA_PDB/$<CONFIG>"
 )
 list(APPEND my_targets mylibA)
 
@@ -87,7 +87,13 @@ foreach(t ${my_targets})
   if(NOT pdb_dir)
     set(pdb_dir ${CMAKE_CURRENT_BINARY_DIR})
   endif()
-  list(APPEND pdbs ${pdb_dir}/${CMAKE_CFG_INTDIR}/${pdb_name}.pdb)
+  if (pdb_dir MATCHES "\\$<.*>")
+    # Skip per-configuration subdirectory if the value contained
+    # a generator expression.
+    list(APPEND pdbs ${pdb_dir}/${pdb_name}.pdb)
+  else()
+    list(APPEND pdbs ${pdb_dir}/${CMAKE_CFG_INTDIR}/${pdb_name}.pdb)
+  endif()
 endforeach()
 add_custom_target(check_pdbs ALL VERBATIM
   COMMAND ${CMAKE_COMMAND} -Dconfig=$<CONFIGURATION> "-Dpdbs=${pdbs}"