[lldb][RISCV] function calls support in lldb expressions

lldb/source/Expression/IRExecutionUnit.cpp

@@ -277,6 +277,12 @@ void IRExecutionUnit::GetRunnableInfo(Status &error, lldb::addr_t &func_addr,
       .setMCJITMemoryManager(std::make_unique<MemoryManager>(*this))
       .setOptLevel(llvm::CodeGenOptLevel::Less);
 
+  // Resulted jitted code can be placed too far from the code in the binary
+  // and thus can contain more than +-2GB jumps, that are not available
+  // in RISC-V without large code model.
+  if (triple.isRISCV64())
+    builder.setCodeModel(llvm::CodeModel::Large);
+
   llvm::StringRef mArch;
   llvm::StringRef mCPU;
   llvm::SmallVector<std::string, 0> mAttrs;

lldb/source/Plugins/ABI/RISCV/ABISysV_riscv.cpp

@@ -10,7 +10,9 @@
 
 #include <array>
 #include <limits>
+#include <sstream>
 
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/IR/DerivedTypes.h"
 
 #include "Utility/RISCV_DWARF_Registers.h"
@@ -20,6 +22,7 @@
 #include "lldb/Target/RegisterContext.h"
 #include "lldb/Target/StackFrame.h"
 #include "lldb/Target/Thread.h"
+#include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/RegisterValue.h"
 
 #define DEFINE_REG_NAME(reg_num) ConstString(#reg_num).GetCString()
@@ -120,6 +123,10 @@ static const std::array<RegisterInfo, 33> g_register_infos = {
 } // namespace dwarf
 } // namespace
 
+// Number of argument registers (the base integer calling convention
+// provides 8 argument registers, a0-a7)
+static constexpr size_t g_regs_for_args_count = 8U;
+
 const RegisterInfo *ABISysV_riscv::GetRegisterInfoArray(uint32_t &count) {
   count = dwarf::g_register_infos.size();
   return dwarf::g_register_infos.data();
@@ -164,11 +171,81 @@ TotalArgsSizeInWords(bool is_rv64,
   return total_size;
 }
 
+static bool UpdateRegister(RegisterContext *reg_ctx,
+                           const lldb::RegisterKind reg_kind,
+                           const uint32_t reg_num, const addr_t value) {
+  Log *log = GetLog(LLDBLog::Expressions);
+
+  const RegisterInfo *reg_info = reg_ctx->GetRegisterInfo(reg_kind, reg_num);
+
+  LLDB_LOG(log, "Writing {0}: 0x{1:x}", reg_info->name,
+           static_cast<uint64_t>(value));
+  if (!reg_ctx->WriteRegisterFromUnsigned(reg_info, value)) {
+    LLDB_LOG(log, "Writing {0}: failed", reg_info->name);
+    return false;
+  }
+  return true;
+}
+
+static void LogInitInfo(Log &log, const Thread &thread, addr_t sp,
+                        addr_t func_addr, addr_t return_addr,
+                        const llvm::ArrayRef<addr_t> args) {
+  std::stringstream ss;
+  ss << "ABISysV_riscv::PrepareTrivialCall"
+     << " (tid = 0x" << std::hex << thread.GetID() << ", sp = 0x" << sp
+     << ", func_addr = 0x" << func_addr << ", return_addr = 0x" << return_addr;
+
+  for (auto [idx, arg] : enumerate(args))
+    ss << ", arg" << std::dec << idx << " = 0x" << std::hex << arg;
+  ss << ")";
+  log.PutString(ss.str());
+}
+
 bool ABISysV_riscv::PrepareTrivialCall(Thread &thread, addr_t sp,
                                        addr_t func_addr, addr_t return_addr,
                                        llvm::ArrayRef<addr_t> args) const {
-  // TODO: Implement
-  return false;
+  Log *log = GetLog(LLDBLog::Expressions);
+  if (log)
+    LogInitInfo(*log, thread, sp, func_addr, return_addr, args);
+
+  const auto reg_ctx_sp = thread.GetRegisterContext();
+  if (!reg_ctx_sp) {
+    LLDB_LOG(log, "Failed to get RegisterContext");
+    return false;
+  }
+
+  if (args.size() > g_regs_for_args_count) {
+    LLDB_LOG(log, "Function has {0} arguments, but only {1} are allowed!",
+             args.size(), g_regs_for_args_count);
+    return false;
+  }
+
+  // Write arguments to registers
+  for (auto [idx, arg] : enumerate(args)) {
+    const RegisterInfo *reg_info = reg_ctx_sp->GetRegisterInfo(
+        eRegisterKindGeneric, LLDB_REGNUM_GENERIC_ARG1 + idx);
+    LLDB_LOG(log, "About to write arg{0} (0x{1:x}) into {2}", idx, arg,
+             reg_info->name);
+
+    if (!reg_ctx_sp->WriteRegisterFromUnsigned(reg_info, arg)) {
+      LLDB_LOG(log, "Failed to write arg{0} (0x{1:x}) into {2}", idx, arg,
+               reg_info->name);
+      return false;
+    }
+  }
+
+  if (!UpdateRegister(reg_ctx_sp.get(), eRegisterKindGeneric,
+                      LLDB_REGNUM_GENERIC_PC, func_addr))
+    return false;
+  if (!UpdateRegister(reg_ctx_sp.get(), eRegisterKindGeneric,
+                      LLDB_REGNUM_GENERIC_SP, sp))
+    return false;
+  if (!UpdateRegister(reg_ctx_sp.get(), eRegisterKindGeneric,
+                      LLDB_REGNUM_GENERIC_RA, return_addr))
+    return false;
+
+  LLDB_LOG(log, "ABISysV_riscv::{0}() success", __FUNCTION__);
+  return true;
 }
 
 bool ABISysV_riscv::PrepareTrivialCall(
@@ -222,14 +299,14 @@ bool ABISysV_riscv::PrepareTrivialCall(
   assert(prototype.getFunctionNumParams() == args.size());
 
   const size_t num_args = args.size();
-  const size_t regs_for_args_count = 8U;
   const size_t num_args_in_regs =
-      num_args > regs_for_args_count ?  regs_for_args_count : num_args;
+      num_args > g_regs_for_args_count ? g_regs_for_args_count : num_args;
 
   // Number of arguments passed on stack.
   size_t args_size = TotalArgsSizeInWords(m_is_rv64, args);
-  auto on_stack =
-      args_size <= regs_for_args_count ? 0 : args_size - regs_for_args_count;
+  auto on_stack = args_size <= g_regs_for_args_count
+                      ? 0
+                      : args_size - g_regs_for_args_count;
   auto offset = on_stack * word_size;
 
   uint8_t reg_value[8];
@@ -260,7 +337,7 @@ bool ABISysV_riscv::PrepareTrivialCall(
       ++reg_index;
     }
 
-    if (reg_index < regs_for_args_count || size == 0)
+    if (reg_index < g_regs_for_args_count || size == 0)
       continue;
 
     // Remaining arguments are passed on the stack.

lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp

@@ -44,6 +44,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/TargetSelect.h"
+#include "llvm/TargetParser/Triple.h"
 
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
@@ -442,24 +443,50 @@ static void SetupDefaultClangDiagnostics(CompilerInstance &compiler) {
 /// \return
 ///     A string representing target ABI for the current architecture.
 static std::string GetClangTargetABI(const ArchSpec &target_arch) {
-  std::string abi;
-
   if (target_arch.IsMIPS()) {
     switch (target_arch.GetFlags() & ArchSpec::eMIPSABI_mask) {
     case ArchSpec::eMIPSABI_N64:
-      abi = "n64";
-      break;
+      return "n64";
     case ArchSpec::eMIPSABI_N32:
-      abi = "n32";
-      break;
+      return "n32";
     case ArchSpec::eMIPSABI_O32:
-      abi = "o32";
-      break;
+      return "o32";
     default:
-      break;
+      return {};
     }
   }
-  return abi;
+
+  if (target_arch.GetTriple().isRISCV64()) {
+    switch (target_arch.GetFlags() & ArchSpec::eRISCV_float_abi_mask) {
+    case ArchSpec::eRISCV_float_abi_soft:
+      return "lp64";
+    case ArchSpec::eRISCV_float_abi_single:
+      return "lp64f";
+    case ArchSpec::eRISCV_float_abi_double:
+      return "lp64d";
+    case ArchSpec::eRISCV_float_abi_quad:
+      return "lp64q";
+    default:
+      return {};
+    }
+  }
+
+  if (target_arch.GetTriple().isRISCV32()) {
+    switch (target_arch.GetFlags() & ArchSpec::eRISCV_float_abi_mask) {
+    case ArchSpec::eRISCV_float_abi_soft:
+      return "ilp32";
+    case ArchSpec::eRISCV_float_abi_single:
+      return "ilp32f";
+    case ArchSpec::eRISCV_float_abi_double:
+      return "ilp32d";
+    case ArchSpec::eRISCV_float_abi_soft | ArchSpec::eRISCV_rve:
+      return "ilp32e";
+    default:
+      return {};
+    }
+  }
+
+  return {};
 }
 
 static void SetupTargetOpts(CompilerInstance &compiler,
@@ -506,6 +533,18 @@ static void SetupTargetOpts(CompilerInstance &compiler,
   // Set the target ABI
   if (std::string abi = GetClangTargetABI(target_arch); !abi.empty())
     compiler.getTargetOpts().ABI = std::move(abi);
+
+  if ((target_machine == llvm::Triple::riscv64 &&
+       compiler.getTargetOpts().ABI == "lp64f") ||
+      (target_machine == llvm::Triple::riscv32 &&
+       compiler.getTargetOpts().ABI == "ilp32f"))
+    compiler.getTargetOpts().FeaturesAsWritten.emplace_back("+f");
+
+  if ((target_machine == llvm::Triple::riscv64 &&
+       compiler.getTargetOpts().ABI == "lp64d") ||
+      (target_machine == llvm::Triple::riscv32 &&
+       compiler.getTargetOpts().ABI == "ilp32d"))
+    compiler.getTargetOpts().FeaturesAsWritten.emplace_back("+d");
 }
 
 static void SetupLangOpts(CompilerInstance &compiler,
@@ -757,7 +796,7 @@ ClangExpressionParser::ClangExpressionParser(
   m_compiler->getCodeGenOpts().EmitDeclMetadata = true;
   m_compiler->getCodeGenOpts().InstrumentFunctions = false;
   m_compiler->getCodeGenOpts().setFramePointer(
-                                    CodeGenOptions::FramePointerKind::All);
+      CodeGenOptions::FramePointerKind::All);
   if (generate_debug_info)
     m_compiler->getCodeGenOpts().setDebugInfo(codegenoptions::FullDebugInfo);
   else
@@ -771,7 +810,7 @@ ClangExpressionParser::ClangExpressionParser(
   // FIXME: We shouldn't need to do this, the target should be immutable once
   // created. This complexity should be lifted elsewhere.
   m_compiler->getTarget().adjust(m_compiler->getDiagnostics(),
-		                 m_compiler->getLangOpts());
+                                 m_compiler->getLangOpts());
 
   // 5. Set up the diagnostic buffer for reporting errors
   auto diag_mgr = new ClangDiagnosticManagerAdapter(
@@ -1191,8 +1230,7 @@ ClangExpressionParser::ParseInternal(DiagnosticManager &diagnostic_manager,
           if (auto fileEntry = m_compiler->getFileManager().getOptionalFileRef(
                   result_path)) {
             source_mgr.setMainFileID(source_mgr.createFileID(
-                *fileEntry,
-                SourceLocation(), SrcMgr::C_User));
+                *fileEntry, SourceLocation(), SrcMgr::C_User));
             created_main_file = true;
           }
         }