[llvm-branch-commits] [llvm] [NVPTX] add support for encoding PTX registers for DWARF (PR #109495)

[Walter Erquinigo via llvm-branch-commits]

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@@ -141,3 +142,47 @@ NVPTXRegisterInfo::getFrameLocalRegister(const MachineFunction &MF) const {
       static_cast<const NVPTXTargetMachine &>(MF.getTarget());
   return TM.is64Bit() ? NVPTX::VRFrameLocal64 : NVPTX::VRFrameLocal32;
 }
+
+void NVPTXRegisterInfo::clearDebugRegisterMap() const {
+  debugRegisterMap.clear();
+}
+
+static uint64_t encodeRegisterForDwarf(std::string registerName) {
+  if (registerName.length() > 8) {
+    // The name is more than 8 characters long, and so won't fit into 64 bits.
+    return 0;
+  }
+
+  // Encode the name string into a DWARF register number using cuda-gdb's
+  // encoding.  See cuda_check_dwarf2_reg_ptx_virtual_register in cuda-tdep.c,
+  // https://github.com/NVIDIA/cuda-gdb/blob/e5cf3bddae520ffb326f95b4d98ce5c7474b828b/gdb/cuda/cuda-tdep.c#L353
+  // IE the bytes of the string are concatenated in reverse into a single
+  // number, which is stored in ULEB128, but in practice must be no more than 8
+  // bytes (excluding null terminator, which is not included).
+  uint64_t result = 0;
+  for (int i = 0; i < registerName.length(); ++i) {
+    result = result << 8;
+    char c = registerName[i];
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walter-erquinigo wrote:

shouldn't this be unsigned char?

https://github.com/llvm/llvm-project/pull/109495