[llvm] MCExpr-ify amd_kernel_code_t (PR #91587)

[Matt Arsenault via llvm-commits]

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@@ -1218,39 +1219,67 @@ unsigned getAllocatedNumVGPRBlocks(const MCSubtargetInfo *STI,
 }
 } // end namespace IsaInfo
 
-void initDefaultAMDKernelCodeT(amd_kernel_code_t &Header,
+void initDefaultAMDKernelCodeT(AMDGPUMCKernelCodeT &KernelCode,
                                const MCSubtargetInfo *STI) {
   IsaVersion Version = getIsaVersion(STI->getCPU());
 
-  memset(&Header, 0, sizeof(Header));
-
-  Header.amd_kernel_code_version_major = 1;
-  Header.amd_kernel_code_version_minor = 2;
-  Header.amd_machine_kind = 1; // AMD_MACHINE_KIND_AMDGPU
-  Header.amd_machine_version_major = Version.Major;
-  Header.amd_machine_version_minor = Version.Minor;
-  Header.amd_machine_version_stepping = Version.Stepping;
-  Header.kernel_code_entry_byte_offset = sizeof(Header);
-  Header.wavefront_size = 6;
+  KernelCode.amd_kernel_code_version_major = 0;
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arsenm wrote:

Can we just keep all of this in the AMDGPUMCKernelCodeT constructor

https://github.com/llvm/llvm-project/pull/91587