Index: lldb/trunk/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
===================================================================
--- lldb/trunk/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
+++ lldb/trunk/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
@@ -630,13 +630,12 @@
         m_flavor.assign("default");
     }
 
-    const char *triple = arch.GetTriple().getTriple().c_str();
     unsigned flavor = ~0U;
+    llvm::Triple triple = arch.GetTriple();
 
     // So far the only supported flavor is "intel" on x86.  The base class will set this
     // correctly coming in.
-    if (arch.GetTriple().getArch() == llvm::Triple::x86
-        || arch.GetTriple().getArch() == llvm::Triple::x86_64)
+    if (triple.getArch() == llvm::Triple::x86 || triple.getArch() == llvm::Triple::x86_64)
     {
         if (m_flavor == "intel")
         {
@@ -649,7 +648,7 @@
     }
 
     ArchSpec thumb_arch(arch);
-    if (arch.GetTriple().getArch() == llvm::Triple::arm || arch.GetTriple().getArch() == llvm::Triple::thumb)
+    if (triple.getArch() == llvm::Triple::arm || triple.getArch() == llvm::Triple::thumb)
     {
         std::string thumb_arch_name (thumb_arch.GetTriple().getArchName().str());
         // Replace "arm" with "thumb" so we get all thumb variants correct
@@ -665,18 +664,27 @@
         thumb_arch.GetTriple().setArchName(llvm::StringRef(thumb_arch_name.c_str()));
     }
 
+    // If no sub architecture specified then use the most recent arm architecture so the
+    // disassembler will return all instruction. Without it we will see a lot of unknow opcode
+    // in case the code uses instructions which are not available in the oldest arm version
+    // (used when no sub architecture is specified)
+    if (triple.getArch() == llvm::Triple::arm && triple.getSubArch() == llvm::Triple::NoSubArch)
+        triple.setArchName("armv8.1a");
+
+    const char *triple_str = triple.getTriple().c_str();
+
     // Cortex-M3 devices (e.g. armv7m) can only execute thumb (T2) instructions,
     // so hardcode the primary disassembler to thumb mode.  Same for Cortex-M4 (armv7em).
     //
     // Handle the Cortex-M0 (armv6m) the same; the ISA is a subset of the T and T32
     // instructions defined in ARMv7-A.
 
-    if ((arch.GetTriple().getArch() == llvm::Triple::arm || arch.GetTriple().getArch() == llvm::Triple::thumb)
+    if ((triple.getArch() == llvm::Triple::arm || triple.getArch() == llvm::Triple::thumb)
         && (arch.GetCore() == ArchSpec::Core::eCore_arm_armv7m
             || arch.GetCore() == ArchSpec::Core::eCore_arm_armv7em
             || arch.GetCore() == ArchSpec::Core::eCore_arm_armv6m))
     {
-        triple = thumb_arch.GetTriple().getTriple().c_str();
+        triple_str = thumb_arch.GetTriple().getTriple().c_str();
     }
 
     const char *cpu = "";
@@ -718,8 +726,8 @@
     }
 
     std::string features_str = "";
-    if (arch.GetTriple().getArch() == llvm::Triple::mips || arch.GetTriple().getArch() == llvm::Triple::mipsel
-        || arch.GetTriple().getArch() == llvm::Triple::mips64 || arch.GetTriple().getArch() == llvm::Triple::mips64el)
+    if (triple.getArch() == llvm::Triple::mips || triple.getArch() == llvm::Triple::mipsel
+        || triple.getArch() == llvm::Triple::mips64 || triple.getArch() == llvm::Triple::mips64el)
     {
         uint32_t arch_flags = arch.GetFlags ();
         if (arch_flags & ArchSpec::eMIPSAse_msa)
@@ -734,7 +742,7 @@
             features_str += "+micromips,";
     }
     
-    m_disasm_ap.reset (new LLVMCDisassembler(triple, cpu, features_str.c_str(), flavor, *this));
+    m_disasm_ap.reset (new LLVMCDisassembler(triple_str, cpu, features_str.c_str(), flavor, *this));
     if (!m_disasm_ap->IsValid())
     {
         // We use m_disasm_ap.get() to tell whether we are valid or not, so if this isn't good for some reason,
@@ -743,7 +751,7 @@
     }
 
     // For arm CPUs that can execute arm or thumb instructions, also create a thumb instruction disassembler.
-    if (arch.GetTriple().getArch() == llvm::Triple::arm || arch.GetTriple().getArch() == llvm::Triple::thumb)
+    if (triple.getArch() == llvm::Triple::arm || triple.getArch() == llvm::Triple::thumb)
     {
         std::string thumb_triple(thumb_arch.GetTriple().getTriple());
         m_alternate_disasm_ap.reset(new LLVMCDisassembler(thumb_triple.c_str(), "", "", flavor, *this));