MSVC: Add abstraction for debug information format

Replace our hard-coded default for `/Zi` with a first-class abstraction
to select the debug information format an enumeration of logical
names.  We've long hesitated to do this because the idea of "debug
information format" touches on related concepts on several platforms.
Avoid that scope creep by simply defining an abstraction that applies
only when targeting the MSVC ABI on Windows.

Removing the old default flag requires a policy because existing
projects may rely on string processing to edit them and choose a
runtime library under the old behavior.  Add policy CMP0141 to
provide compatibility.

Fixes: #10189

4 files changed, 52 insertions, 1 deletions

diff --git a/Source/cmCoreTryCompile.cxx b/Source/cmCoreTryCompile.cxx
index 0a6c359..85ffd3b 100644
--- a/Source/cmCoreTryCompile.cxx
+++ b/Source/cmCoreTryCompile.cxx
@@ -94,6 +94,8 @@ std::string const kCMAKE_TRY_COMPILE_PLATFORM_VARIABLES =
 std::string const kCMAKE_WARN_DEPRECATED = "CMAKE_WARN_DEPRECATED";
 std::string const kCMAKE_WATCOM_RUNTIME_LIBRARY_DEFAULT =
   "CMAKE_WATCOM_RUNTIME_LIBRARY_DEFAULT";
+std::string const kCMAKE_MSVC_DEBUG_INFORMATION_FORMAT_DEFAULT =
+  "CMAKE_MSVC_DEBUG_INFORMATION_FORMAT_DEFAULT";
 
 /* GHS Multi platform variables */
 std::set<std::string> const ghs_platform_vars{
@@ -497,6 +499,14 @@ bool cmCoreTryCompile::TryCompileCode(Arguments& arguments,
               *cmp0123 == "NEW"_s ? "NEW" : "OLD");
     }
 
+    /* Set MSVC debug information format policy to match our selection.  */
+    if (cmValue msvcDebugInformationFormatDefault =
+          this->Makefile->GetDefinition(
+            kCMAKE_MSVC_DEBUG_INFORMATION_FORMAT_DEFAULT)) {
+      fprintf(fout, "cmake_policy(SET CMP0141 %s)\n",
+              !msvcDebugInformationFormatDefault->empty() ? "NEW" : "OLD");
+    }
+
     /* Set cache/normal variable policy to match outer project.
        It may affect toolchain files.  */
     if (this->Makefile->GetPolicyStatus(cmPolicies::CMP0126) !=
@@ -849,6 +859,7 @@ bool cmCoreTryCompile::TryCompileCode(Arguments& arguments,
     vars.insert(kCMAKE_WARN_DEPRECATED);
     vars.emplace("CMAKE_MSVC_RUNTIME_LIBRARY"_s);
     vars.emplace("CMAKE_WATCOM_RUNTIME_LIBRARY"_s);
+    vars.emplace("CMAKE_MSVC_DEBUG_INFORMATION_FORMAT"_s);
 
     if (cmValue varListStr = this->Makefile->GetDefinition(
           kCMAKE_TRY_COMPILE_PLATFORM_VARIABLES)) {
diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index b44d2a0..defcba3 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -2041,6 +2041,41 @@ void cmLocalGenerator::AddLanguageFlags(std::string& flags,
       }
     }
   }
+
+  // Add MSVC debug information format flags. This is activated by the presence
+  // of a default selection whether or not it is overridden by a property.
+  cmValue msvcDebugInformationFormatDefault = this->Makefile->GetDefinition(
+    "CMAKE_MSVC_DEBUG_INFORMATION_FORMAT_DEFAULT");
+  if (cmNonempty(msvcDebugInformationFormatDefault)) {
+    cmValue msvcDebugInformationFormatValue =
+      target->GetProperty("MSVC_DEBUG_INFORMATION_FORMAT");
+    if (!msvcDebugInformationFormatValue) {
+      msvcDebugInformationFormatValue = msvcDebugInformationFormatDefault;
+    }
+    std::string const msvcDebugInformationFormat =
+      cmGeneratorExpression::Evaluate(*msvcDebugInformationFormatValue, this,
+                                      config, target);
+    if (!msvcDebugInformationFormat.empty()) {
+      if (cmValue msvcDebugInformationFormatOptions =
+            this->Makefile->GetDefinition(
+              cmStrCat("CMAKE_", lang,
+                       "_COMPILE_OPTIONS_MSVC_DEBUG_INFORMATION_FORMAT_",
+                       msvcDebugInformationFormat))) {
+        this->AppendCompileOptions(flags, *msvcDebugInformationFormatOptions);
+      } else if ((this->Makefile->GetSafeDefinition(
+                    cmStrCat("CMAKE_", lang, "_COMPILER_ID")) == "MSVC"_s ||
+                  this->Makefile->GetSafeDefinition(
+                    cmStrCat("CMAKE_", lang, "_SIMULATE_ID")) == "MSVC"_s) &&
+                 !cmSystemTools::GetErrorOccurredFlag()) {
+        // The compiler uses the MSVC ABI so it needs a known runtime library.
+        this->IssueMessage(MessageType::FATAL_ERROR,
+                           cmStrCat("MSVC_DEBUG_INFORMATION_FORMAT value '",
+                                    msvcDebugInformationFormat,
+                                    "' not known for this ", lang,
+                                    " compiler."));
+      }
+    }
+  }
 }
 
 void cmLocalGenerator::AddLanguageFlagsForLinking(
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index fdda31e..ea25814 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -423,7 +423,11 @@ class cmMakefile;
     "The if() command supports path comparisons using PATH_EQUAL operator.",  \
     3, 24, 0, cmPolicies::WARN)                                               \
   SELECT(POLICY, CMP0140, "The return() command checks its arguments.", 3,    \
-         25, 0, cmPolicies::WARN)
+         25, 0, cmPolicies::WARN)                                             \
+  SELECT(                                                                     \
+    POLICY, CMP0141,                                                          \
+    "MSVC debug information format flags are selected by an abstraction.", 3, \
+    25, 0, cmPolicies::WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
 #define CM_FOR_EACH_POLICY_ID(POLICY)                                         \
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index eb3feaa..df2bdba 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -563,6 +563,7 @@ cmTarget::cmTarget(std::string const& name, cmStateEnums::TargetType type,
     initProp("AUTORCC_OPTIONS");
     initProp("LINK_DEPENDS_NO_SHARED");
     initProp("LINK_INTERFACE_LIBRARIES");
+    initProp("MSVC_DEBUG_INFORMATION_FORMAT");
     initProp("MSVC_RUNTIME_LIBRARY");
     initProp("WATCOM_RUNTIME_LIBRARY");
     initProp("WIN32_EXECUTABLE");