[llvm] [yaml2obj][XOFF] Update yaml2obj for XCOFF to create valid XCOFF files in more cases. (PR #77620)

[James Henderson via llvm-commits]

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@@ -254,12 +310,20 @@ bool XCOFFWriter::initFileHeader(uint64_t CurrentOffset) {
 
   // Calculate SymbolTableOffset for the file header.
   if (InitFileHdr.NumberOfSymTableEntries) {
+    if (Obj.Header.SymbolTableOffset) {
+      if (CurrentOffset > Obj.Header.SymbolTableOffset) {
+        ErrOverwrite(CurrentOffset, Obj.Header.SymbolTableOffset,
+                     "SymbolTableOffset");
+        return false;
+      }
+      CurrentOffset = Obj.Header.SymbolTableOffset;
+    }
     InitFileHdr.SymbolTableOffset = CurrentOffset;
     CurrentOffset +=
         InitFileHdr.NumberOfSymTableEntries * XCOFF::SymbolTableEntrySize;
     if (CurrentOffset > MaxRawDataSize) {
-      ErrHandler("maximum object size of" + Twine(MaxRawDataSize) +
-                 "exceeded when writing symbols");
+      ErrHandler("maximum object size of " + Twine(MaxRawDataSize) +
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jh7370 wrote:

Is this tested?

https://github.com/llvm/llvm-project/pull/77620