1 files changed, 11 insertions, 88 deletions

diff --git a/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp b/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp
index 10bbae5664918..41d146f245269 100644
--- a/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp
+++ b/source/Plugins/ABI/SysV-x86_64/ABISysV_x86_64.cpp
@@ -13,6 +13,7 @@
 // C++ Includes
 // Other libraries and framework includes
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
 
 // Project includes
@@ -1160,48 +1161,6 @@ bool ABISysV_x86_64::PrepareTrivialCall(Thread &thread, addr_t sp,
   ProcessSP process_sp(thread.GetProcess());
 
   RegisterValue reg_value;
-
-#if 0
-    // This code adds an extra frame so that we don't lose the function that we came from
-    // by pushing the PC and the FP and then writing the current FP to point to the FP value
-    // we just pushed. It is disabled for now until the stack backtracing code can be debugged.
-
-    // Save current PC
-    const RegisterInfo *fp_reg_info = reg_ctx->GetRegisterInfo (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FP);
-    if (reg_ctx->ReadRegister(pc_reg_info, reg_value))
-    {
-        if (log)
-            log->Printf("Pushing the current PC onto the stack: 0x%" PRIx64 ": 0x%" PRIx64, (uint64_t)sp, reg_value.GetAsUInt64());
-        
-        if (!process_sp->WritePointerToMemory(sp, reg_value.GetAsUInt64(), error))
-            return false;
-
-        sp -= 8;
-        
-        // Save current FP
-        if (reg_ctx->ReadRegister(fp_reg_info, reg_value))
-        {
-            if (log)
-                log->Printf("Pushing the current FP onto the stack: 0x%" PRIx64 ": 0x%" PRIx64, (uint64_t)sp, reg_value.GetAsUInt64());
-            
-            if (!process_sp->WritePointerToMemory(sp, reg_value.GetAsUInt64(), error))
-                return false;
-        }
-        // Setup FP backchain
-        reg_value.SetUInt64 (sp);
-        
-        if (log)
-            log->Printf("Writing FP:  0x%" PRIx64 " (for FP backchain)", reg_value.GetAsUInt64());
-
-        if (!reg_ctx->WriteRegister(fp_reg_info, reg_value))
-        {
-            return false;
-        }
-        
-        sp -= 8;
-    }
-#endif
-
   if (log)
     log->Printf("Pushing the return address onto the stack: 0x%" PRIx64
                 ": 0x%" PRIx64,
@@ -1908,52 +1867,16 @@ bool ABISysV_x86_64::RegisterIsVolatile(const RegisterInfo *reg_info) {
 // It's being revised & updated at https://github.com/hjl-tools/x86-psABI/
 
 bool ABISysV_x86_64::RegisterIsCalleeSaved(const RegisterInfo *reg_info) {
-  if (reg_info) {
-    // Preserved registers are :
-    //    rbx, rsp, rbp, r12, r13, r14, r15
-    //    mxcsr (partially preserved)
-    //    x87 control word
-
-    const char *name = reg_info->name;
-    if (name[0] == 'r') {
-      switch (name[1]) {
-      case '1': // r12, r13, r14, r15
-        if (name[2] >= '2' && name[2] <= '5')
-          return name[3] == '\0';
-        break;
-
-      default:
-        break;
-      }
-    }
-
-    // Accept shorter-variant versions, rbx/ebx, rip/ eip, etc.
-    if (name[0] == 'r' || name[0] == 'e') {
-      switch (name[1]) {
-      case 'b': // rbp, rbx
-        if (name[2] == 'p' || name[2] == 'x')
-          return name[3] == '\0';
-        break;
-
-      case 'i': // rip
-        if (name[2] == 'p')
-          return name[3] == '\0';
-        break;
-
-      case 's': // rsp
-        if (name[2] == 'p')
-          return name[3] == '\0';
-        break;
-      }
-    }
-    if (name[0] == 's' && name[1] == 'p' && name[2] == '\0') // sp
-      return true;
-    if (name[0] == 'f' && name[1] == 'p' && name[2] == '\0') // fp
-      return true;
-    if (name[0] == 'p' && name[1] == 'c' && name[2] == '\0') // pc
-      return true;
-  }
-  return false;
+  if (!reg_info)
+    return false;
+  assert(reg_info->name != nullptr && "unnamed register?");
+  std::string Name = std::string(reg_info->name);
+  bool IsCalleeSaved =
+      llvm::StringSwitch<bool>(Name)
+          .Cases("r12", "r13", "r14", "r15", "rbp", "ebp", "rbx", "ebx", true)
+          .Cases("rip", "eip", "rsp", "esp", "sp", "fp", "pc", true)
+          .Default(false);
+  return IsCalleeSaved;
 }
 
 void ABISysV_x86_64::Initialize() {