Provide option to set pc of the file loaded in memory.

Summary: This commit adds an option to set PC to the entry point of the file loaded using "target module load" command. In D28804, Greg asked me to separate this part under a different option.

Reviewers: clayborg

Reviewed By: clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D28944

llvm-svn: 292989

lldb/include/lldb/Core/Module.h

@@ -974,7 +974,7 @@ class Module : public std::enable_shared_from_this<Module>,
   ///
   /// @return
   //------------------------------------------------------------------
-  Error LoadInMemory(Target &target);
+  Error LoadInMemory(Target &target, bool set_pc);
 
   //----------------------------------------------------------------------
   /// @class LookupInfo Module.h "lldb/Core/Module.h"

lldb/include/lldb/Symbol/ObjectFile.h

@@ -786,7 +786,7 @@ class ObjectFile : public std::enable_shared_from_this<ObjectFile>,
   ///
   /// @return
   //------------------------------------------------------------------
-  virtual Error LoadInMemory(Target &target);
+  virtual Error LoadInMemory(Target &target, bool set_pc);
 
 protected:
   //------------------------------------------------------------------

lldb/source/Commands/CommandObjectTarget.cpp

@@ -2568,8 +2568,11 @@ class CommandObjectTargetModulesLoad
         m_file_option(LLDB_OPT_SET_1, false, "file", 'f', 0, eArgTypeName,
                       "Fullpath or basename for module to load.", ""),
         m_load_option(LLDB_OPT_SET_1, false, "load", 'l',
-                      "Write file contents to the memory.",
-                      false, true),
+                      "Write file contents to the memory.", false, true),
+        m_pc_option(LLDB_OPT_SET_1, false, "--set-pc-to-entry", 'p',
+                    "Set PC to the entry point."
+                    " Only applicable with '--load' option.",
+                    false, true),
         m_slide_option(LLDB_OPT_SET_1, false, "slide", 's', 0, eArgTypeOffset,
                        "Set the load address for all sections to be the "
                        "virtual address in the file plus the offset.",
@@ -2578,6 +2581,7 @@ class CommandObjectTargetModulesLoad
                           LLDB_OPT_SET_1);
     m_option_group.Append(&m_file_option, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
     m_option_group.Append(&m_load_option, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
+    m_option_group.Append(&m_pc_option, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
     m_option_group.Append(&m_slide_option, LLDB_OPT_SET_ALL, LLDB_OPT_SET_1);
     m_option_group.Finalize();
   }
@@ -2590,6 +2594,7 @@ class CommandObjectTargetModulesLoad
   bool DoExecute(Args &args, CommandReturnObject &result) override {
     Target *target = m_interpreter.GetDebugger().GetSelectedTarget().get();
     const bool load = m_load_option.GetOptionValue().GetCurrentValue();
+    const bool set_pc = m_pc_option.GetOptionValue().GetCurrentValue();
     if (target == nullptr) {
       result.AppendError("invalid target, create a debug target using the "
                          "'target create' command");
@@ -2742,7 +2747,7 @@ class CommandObjectTargetModulesLoad
                     process->Flush();
                 }
                 if (load) {
-                  Error error = module->LoadInMemory(*target);
+                  Error error = module->LoadInMemory(*target, set_pc);
                   if (error.Fail()) {
                     result.AppendError(error.AsCString());
                     return false;
@@ -2811,6 +2816,7 @@ class CommandObjectTargetModulesLoad
   OptionGroupUUID m_uuid_option_group;
   OptionGroupString m_file_option;
   OptionGroupBoolean m_load_option;
+  OptionGroupBoolean m_pc_option;
   OptionGroupUInt64 m_slide_option;
 };
 

lldb/source/Core/Module.cpp

@@ -1665,6 +1665,6 @@ bool Module::GetIsDynamicLinkEditor() {
   return false;
 }
 
-Error Module::LoadInMemory(Target &target) {
-  return m_objfile_sp->LoadInMemory(target);
+Error Module::LoadInMemory(Target &target, bool set_pc) {
+  return m_objfile_sp->LoadInMemory(target, set_pc);
 }

lldb/source/Symbol/ObjectFile.cpp

@@ -652,11 +652,13 @@ ConstString ObjectFile::GetNextSyntheticSymbolName() {
   return ConstString(ss.GetString());
 }
 
-Error ObjectFile::LoadInMemory(Target &target) {
+Error ObjectFile::LoadInMemory(Target &target, bool set_pc) {
   Error error;
   ProcessSP process = target.CalculateProcess();
   if (!process)
     return Error("No Process");
+  if (set_pc && !GetEntryPointAddress().IsValid())
+    return Error("No entry address in object file");
 
   SectionList *section_list = GetSectionList();
   if (!section_list)
@@ -677,5 +679,12 @@ Error ObjectFile::LoadInMemory(Target &target) {
         return error;
     }
   }
+  if (set_pc) {
+    ThreadList &thread_list = process->GetThreadList();
+    ThreadSP curr_thread(thread_list.GetSelectedThread());
+    RegisterContextSP reg_context(curr_thread->GetRegisterContext());
+    Address file_entry = GetEntryPointAddress();
+    reg_context->SetPC(file_entry.GetLoadAddress(&target));
+  }
   return error;
 }