Move the scratch buffer allocation for x86 instructions from being allocated each instruction,

to once in the AssemblyParse_x86 ctor.
an instruction

llvm-svn: 165662

1 files changed, 9 insertions, 7 deletions

diff --git a/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
index 4094ccf6670..6ff3c522524 100644
--- a/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
+++ b/lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
@@ -161,6 +161,7 @@ private:
     int m_cpu;
     ArchSpec m_arch;
     ::LLVMDisasmContextRef m_disasm_context;
+    uint8_t *m_opcode_data;
 
     DISALLOW_COPY_AND_ASSIGN (AssemblyParse_x86);
 };
@@ -177,7 +178,8 @@ AssemblyParse_x86::AssemblyParse_x86 (const ExecutionContext &exe_ctx, int cpu,
     m_lldb_fp_regnum (LLDB_INVALID_REGNUM),
     m_wordsize (-1), 
     m_cpu(cpu),
-    m_arch(arch)
+    m_arch(arch),
+    m_opcode_data(NULL)
 {
     int *initialized_flag = NULL;
     if (cpu == k_i386)
@@ -247,10 +249,13 @@ AssemblyParse_x86::AssemblyParse_x86 (const ExecutionContext &exe_ctx, int cpu,
                                           /*TagType=*/1,
                                           NULL,
                                           NULL);
+   m_opcode_data = (uint8_t *) malloc (m_arch.GetMaximumOpcodeByteSize());
 }
 
 AssemblyParse_x86::~AssemblyParse_x86 ()
 {
+    if (m_opcode_data)
+        free (m_opcode_data);
     ::LLVMDisasmDispose(m_disasm_context);
 }
 
@@ -474,8 +479,7 @@ AssemblyParse_x86::instruction_length (Address addr, int &length)
     if (!addr.IsValid())
         return false;
 
-    uint8_t *opcode_data = (uint8_t *) malloc (max_op_byte_size);
-    if (opcode_data == NULL)
+    if (m_opcode_data == NULL)
     {
         return false;
     }
@@ -483,23 +487,21 @@ AssemblyParse_x86::instruction_length (Address addr, int &length)
     const bool prefer_file_cache = true;
     Error error;
     Target *target = m_exe_ctx.GetTargetPtr();
-    if (target->ReadMemory (addr, prefer_file_cache, opcode_data, max_op_byte_size, error) == -1)
+    if (target->ReadMemory (addr, prefer_file_cache, m_opcode_data, max_op_byte_size, error) == -1)
     {
-        free (opcode_data);
         return false;
     }
    
     char out_string[512];
     const addr_t pc = addr.GetFileAddress();
     const size_t inst_size = ::LLVMDisasmInstruction (m_disasm_context,
-                                                      opcode_data,
+                                                      m_opcode_data,
                                                       max_op_byte_size,
                                                       pc, // PC value
                                                       out_string,
                                                       sizeof(out_string));
 
     length = inst_size;
-    free (opcode_data);
     return true;
 }