[llvm] [Object][COFF][llvm-readobj] Add support for ARM64X dynamic relocations. (PR #97229)

[Eli Friedman via llvm-commits]

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@@ -800,6 +800,218 @@ Error COFFObjectFile::initLoadConfigPtr() {
     }
   }
 
+  // Interpret and validate dynamic relocations.
+  uint32_t DynamicRelocTableOffset = 0, DynamicRelocTableSection = 0;
+  if (is64()) {
+    auto Config = getLoadConfig64();
+    if (Config->Size >=
+        offsetof(coff_load_configuration64, DynamicValueRelocTableSection) +
+            sizeof(Config->DynamicValueRelocTableSection)) {
+      DynamicRelocTableSection = Config->DynamicValueRelocTableSection;
+      DynamicRelocTableOffset = Config->DynamicValueRelocTableOffset;
+    }
+  } else {
+    auto Config = getLoadConfig32();
+    if (Config->Size >=
+        offsetof(coff_load_configuration32, DynamicValueRelocTableSection) +
+            sizeof(Config->DynamicValueRelocTableSection)) {
+      DynamicRelocTableSection = Config->DynamicValueRelocTableSection;
+      DynamicRelocTableOffset = Config->DynamicValueRelocTableOffset;
+    }
+  }
+
+  Expected<const coff_section *> Section = getSection(DynamicRelocTableSection);
+  if (!Section)
+    return Section.takeError();
+  if (*Section) {
+    ArrayRef<uint8_t> Contents;
+    if (Error E = getSectionContents(*Section, Contents))
+      return E;
+
+    Contents = Contents.drop_front(DynamicRelocTableOffset);
+    if (Contents.size() < sizeof(coff_dynamic_reloc_table))
+      return createStringError(object_error::parse_failed,
+                               "Too large DynamicValueRelocTableOffset (" +
+                                   Twine(DynamicRelocTableOffset) + ")");
+
+    DynamicRelocTable =
+        reinterpret_cast<const coff_dynamic_reloc_table *>(Contents.data());
+
+    if (DynamicRelocTable->Version != 1 && DynamicRelocTable->Version != 2) {
+      DynamicRelocTable = nullptr;
+      return Error::success();
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efriedma-quic wrote:

Why is this not an error?

https://github.com/llvm/llvm-project/pull/97229