[llvm] [clang] [SystemZ][z/OS] This change adds support for the PPA2 section in zOS (PR #68926)

[Ulrich Weigand via cfe-commits]

================
@@ -1026,6 +1030,78 @@ void SystemZAsmPrinter::emitADASection() {
   OutStreamer->popSection();
 }
 
+static uint32_t getProductVersion(Module &M) {
+  if (auto *VersionVal = cast_or_null<ConstantAsMetadata>(
+          M.getModuleFlag("zos_product_major_version")))
+    return cast<ConstantInt>(VersionVal->getValue())->getZExtValue();
+  return LLVM_VERSION_MAJOR;
+}
+
+static uint32_t getProductRelease(Module &M) {
+  if (auto *ReleaseVal = cast_or_null<ConstantAsMetadata>(
+          M.getModuleFlag("zos_product_minor_version")))
+    return cast<ConstantInt>(ReleaseVal->getValue())->getZExtValue();
+  return LLVM_VERSION_MINOR;
+}
+
+static uint32_t getProductPatch(Module &M) {
+  if (auto *PatchVal = cast_or_null<ConstantAsMetadata>(
+          M.getModuleFlag("zos_product_patchlevel")))
+    return cast<ConstantInt>(PatchVal->getValue())->getZExtValue();
+  return LLVM_VERSION_PATCH;
+}
+
+static time_t getTranslationTime(Module &M) {
+  std::time_t Time = 0;
+  if (auto *Val = cast_or_null<ConstantAsMetadata>(
+          M.getModuleFlag("zos_translation_time"))) {
+    long SecondsSinceEpoch = cast<ConstantInt>(Val->getValue())->getSExtValue();
+    Time = static_cast<time_t>(SecondsSinceEpoch);
+  }
+  return Time;
+}
+
+void SystemZAsmPrinter::emitIDRLSection(Module &M) {
+  OutStreamer->pushSection();
+  OutStreamer->switchSection(getObjFileLowering().getIDRLSection());
+  constexpr unsigned IDRLDataLength = 30;
+  std::time_t Time = getTranslationTime(M);
+
+  uint32_t ProductVersion = getProductVersion(M);
+  uint32_t ProductRelease = getProductRelease(M);
+
+  std::string ProductID;
+  if (auto *MD = M.getModuleFlag("zos_product_id"))
+    ProductID = cast<MDString>(MD)->getString().str();
+
+  if (ProductID.empty()) {
+    char ProductIDFormatted[11]; // 10 + null.
+    snprintf(ProductIDFormatted, sizeof(ProductIDFormatted), "LLVM  %02d%02d",
+             ProductVersion, ProductRelease);
----------------
uweigand wrote:

In this case, `ProductVersion` and `ProductRelease` seem to be present twice, first as part of the ID and then again separately.  (This is different from when clang sets the ID as just "clang".)  Is this deliberate?

https://github.com/llvm/llvm-project/pull/68926