[llvm] [X86] Disallow immediate address calls when position independent (PR #202370)

[Phoebe Wang via llvm-commits]

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@@ -241,7 +241,7 @@ bool X86Subtarget::isLegalToCallImmediateAddr() const {
   // FIXME: I386 PE/COFF supports PC relative calls using IMAGE_REL_I386_REL32
   // but WinCOFFObjectWriter::RecordRelocation cannot emit them.  Once it does,
   // the following check for Win32 should be removed.
-  if (Is64Bit || isTargetWin32())
+  if (Is64Bit || isTargetWin32() || isPositionIndependent())
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phoebewang wrote:

I'm not experienced in the involved code here. I just want to be cautious given it looks like a behavioral change of long existing code.

I skimed the related link and issues. It looks like the absolute address is not intended. Maybe we can try to avoid the generation of it. Is there a simple C reproducer? I'd like to see how GCC handles it as a comparison.

https://github.com/llvm/llvm-project/pull/202370