[llvm] [llvm-objdump] Print out xcoff load section of xcoff object file with option private-headers (PR #121226)

[zhijian lin via llvm-commits]

================
@@ -262,6 +264,45 @@ void XCOFFDumper::printAuxiliaryHeader(
                                    AuxSize, *AuxHeader);
 }
 
+void XCOFFDumper::printLoaderSectionHeader() {
+  Expected<uintptr_t> LoaderSectionAddrOrError =
+      Obj.getSectionFileOffsetToRawData(XCOFF::STYP_LOADER);
+  if (!LoaderSectionAddrOrError) {
+    reportUniqueWarning(LoaderSectionAddrOrError.takeError());
+    return;
+  }
+  uintptr_t LoaderSectionAddr = LoaderSectionAddrOrError.get();
+
+  if (LoaderSectionAddr == 0)
+    return;
+
+  auto PrintLoadSecHeaderCommon = [&](const auto *LDHeader) {
+    printNumber("Version:", LDHeader->Version);
+    printNumber("NumberOfSymbolEntries:", LDHeader->NumberOfSymTabEnt);
+    printNumber("NumberOfRelocationEntries:", LDHeader->NumberOfRelTabEnt);
+    printNumber("LengthOfImportFileIDStringTable:",
+                LDHeader->LengthOfImpidStrTbl);
+    printNumber("NumberOfImportFileIDs:", LDHeader->NumberOfImpid);
+    printHex("OffsetToImportFileIDs:", LDHeader->OffsetToImpid);
+    printNumber("LengthOfStringTable:", LDHeader->LengthOfStrTbl);
+    printHex("OffsetToStringTable:", LDHeader->OffsetToStrTbl);
+  };
+
+  Width = 35;
+  outs() << "\n---Loader Section Header:\n";
+  if (Obj.is64Bit()) {
+    const LoaderSectionHeader64 *LoaderSec64 =
+        reinterpret_cast<const LoaderSectionHeader64 *>(LoaderSectionAddr);
----------------
diggerlin wrote:

If I understand your question correctly. I wrote a following test case and run , it do not crash. it looks the PowerPC do not need to be alignment on the memory in when reading the data.

```
bash> cat test.cpp
unsigned int var =10;
int main() {
 char *cvar = reinterpret_cast<char *>(&var)+1;

 int *us = reinterpret_cast<int *>(cvar);
 (*us)++;
 return *us;
}
```

https://github.com/llvm/llvm-project/pull/121226