[lldb] Add support for MSP430 in LLDB.

Add MSP430 to the list of available targets, implement MSP430 ABI, add support for debugging targets with 16-bit address size.

The update is intended for use with MSPDebug, a GDB server implementation for MSP430.

Reviewed By: bulbazord, DavidSpickett

Differential Revision: https://reviews.llvm.org/D146965

lldb/include/lldb/Utility/ArchSpec.h

@@ -172,6 +172,8 @@ class ArchSpec {
     eCore_mips64r5el,
     eCore_mips64r6el,
 
+    eCore_msp430,
+
     eCore_ppc_generic,
     eCore_ppc_ppc601,
     eCore_ppc_ppc602,

lldb/include/lldb/Utility/DataExtractor.h

@@ -843,9 +843,7 @@ class DataExtractor {
   /// \param[in] addr_size
   ///     The size in bytes to use when extracting addresses.
   void SetAddressByteSize(uint32_t addr_size) {
-#ifdef LLDB_CONFIGURATION_DEBUG
-    assert(addr_size == 4 || addr_size == 8);
-#endif
+    assert(addr_size == 2 || addr_size == 4 || addr_size == 8);
     m_addr_size = addr_size;
   }
 

lldb/source/Expression/IRMemoryMap.cpp

@@ -96,12 +96,21 @@ lldb::addr_t IRMemoryMap::FindSpace(size_t size) {
   // regions, walk forward through memory until a region is found that has
   // adequate space for our allocation.
   if (process_is_alive) {
-    const uint64_t end_of_memory = process_sp->GetAddressByteSize() == 8
-                                       ? 0xffffffffffffffffull
-                                       : 0xffffffffull;
-
-    lldbassert(process_sp->GetAddressByteSize() == 4 ||
-               end_of_memory != 0xffffffffull);
+    uint64_t end_of_memory;
+    switch (process_sp->GetAddressByteSize()) {
+    case 2:
+      end_of_memory = 0xffffull;
+      break;
+    case 4:
+      end_of_memory = 0xffffffffull;
+      break;
+    case 8:
+      end_of_memory = 0xffffffffffffffffull;
+      break;
+    default:
+      lldbassert(false && "Invalid address size.");
+      return LLDB_INVALID_ADDRESS;
+    }
 
     MemoryRegionInfo region_info;
     Status err = process_sp->GetMemoryRegionInfo(ret, region_info);
@@ -137,26 +146,31 @@ lldb::addr_t IRMemoryMap::FindSpace(size_t size) {
   // We've tried our algorithm, and it didn't work.  Now we have to reset back
   // to the end of the allocations we've already reported, or use a 'sensible'
   // default if this is our first allocation.
-
   if (m_allocations.empty()) {
     uint32_t address_byte_size = GetAddressByteSize();
     if (address_byte_size != UINT32_MAX) {
       switch (address_byte_size) {
-      case 8:
-        ret = 0xdead0fff00000000ull;
+      case 2:
+        ret = 0x8000ull;
         break;
       case 4:
         ret = 0xee000000ull;
         break;
-      default:
+      case 8:
+        ret = 0xdead0fff00000000ull;
         break;
+      default:
+        lldbassert(false && "Invalid address size.");
+        return LLDB_INVALID_ADDRESS;
       }
     }
   } else {
     auto back = m_allocations.rbegin();
     lldb::addr_t addr = back->first;
     size_t alloc_size = back->second.m_size;
-    ret = llvm::alignTo(addr + alloc_size, 4096);
+    auto arch = target_sp->GetArchitecture().GetTriple().getArch();
+    auto align = arch == llvm::Triple::msp430 ? 512 : 4096;
+    ret = llvm::alignTo(addr + alloc_size, align);
   }
 
   return ret;

lldb/source/Expression/LLVMUserExpression.cpp

@@ -333,7 +333,9 @@ bool LLVMUserExpression::PrepareToExecuteJITExpression(
     if (m_can_interpret && m_stack_frame_bottom == LLDB_INVALID_ADDRESS) {
       Status alloc_error;
 
-      const size_t stack_frame_size = 512 * 1024;
+      auto arch = target->GetArchitecture().GetTriple().getArch();
+      const size_t stack_frame_size =
+          arch == llvm::Triple::msp430 ? 512 : 512 * 1024;
 
       const bool zero_memory = false;
 

lldb/source/Host/common/NativeProcessProtocol.cpp

@@ -503,6 +503,7 @@ NativeProcessProtocol::GetSoftwareBreakpointTrapOpcode(size_t size_hint) {
   static const uint8_t g_i386_opcode[] = {0xCC};
   static const uint8_t g_mips64_opcode[] = {0x00, 0x00, 0x00, 0x0d};
   static const uint8_t g_mips64el_opcode[] = {0x0d, 0x00, 0x00, 0x00};
+  static const uint8_t g_msp430_opcode[] = {0x43, 0x43};
   static const uint8_t g_s390x_opcode[] = {0x00, 0x01};
   static const uint8_t g_ppc_opcode[] = {0x7f, 0xe0, 0x00, 0x08};   // trap
   static const uint8_t g_ppcle_opcode[] = {0x08, 0x00, 0xe0, 0x7f}; // trap
@@ -528,6 +529,9 @@ NativeProcessProtocol::GetSoftwareBreakpointTrapOpcode(size_t size_hint) {
   case llvm::Triple::mips64el:
     return llvm::ArrayRef(g_mips64el_opcode);
 
+  case llvm::Triple::msp430:
+    return llvm::ArrayRef(g_msp430_opcode);
+
   case llvm::Triple::systemz:
     return llvm::ArrayRef(g_s390x_opcode);
 

lldb/source/Plugins/ABI/CMakeLists.txt

@@ -1,4 +1,4 @@
-foreach(target AArch64 ARM ARC Hexagon Mips PowerPC SystemZ X86)
+foreach(target AArch64 ARM ARC Hexagon Mips MSP430 PowerPC SystemZ X86)
   if (${target} IN_LIST LLVM_TARGETS_TO_BUILD)
     add_subdirectory(${target})
   endif()