[Lldb-commits] [lldb] r221213 - Fixed SBTarget::ReadMemory() to work correctly and the TestTargetAPI.py test case that was reading target memory in TargetAPITestCase.test_read_memory_with_dsym and TargetAPITestCase.test_read_memory_with_dwarf.

[Greg Clayton]

Author: gclayton
Date: Mon Nov  3 18:56:30 2014
New Revision: 221213

URL: http://llvm.org/viewvc/llvm-project?rev=221213&view=rev
Log:
Fixed SBTarget::ReadMemory() to work correctly and the TestTargetAPI.py test case that was reading target memory in TargetAPITestCase.test_read_memory_with_dsym and TargetAPITestCase.test_read_memory_with_dwarf.

The problem was that SBTarget::ReadMemory() was making a new section offset lldb_private::Address by doing:


size_t
SBTarget::ReadMemory (const SBAddress addr,
                      void *buf,
                      size_t size,
                      lldb::SBError &error)
{
        ...
        lldb_private::Address addr_priv(addr.GetFileAddress(), NULL);
        bytes_read = target_sp->ReadMemory(addr_priv, false, buf, size, err_priv);


This is wrong. If you get the file addresss from the "addr" argument and try to read memory using that, it will think the file address is a load address and it will try to resolve it accordingly. This will work fine if your executable is loaded at the same address (no slide), but it won't work if there is a slide.

The fix is to just pass along the "addr.ref()" instead of making a new addr_priv as this will pass along the lldb_private::Address that is inside the SBAddress (which is what we want), and not always change it into something that becomes a load address (if we are running), or abmigious file address (think address zero when you have 150 shared libraries that have sections that start at zero, which one would you pick). The main reason for passing a section offset address to SBTarget::ReadMemory() is so you _can_ read from the actual section + offset that is specified in the SBAddress. 



Modified:
    lldb/trunk/source/API/SBTarget.cpp
    lldb/trunk/test/python_api/target/TestTargetAPI.py

Modified: lldb/trunk/source/API/SBTarget.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/API/SBTarget.cpp?rev=221213&r1=221212&r2=221213&view=diff
==============================================================================
--- lldb/trunk/source/API/SBTarget.cpp (original)
+++ lldb/trunk/source/API/SBTarget.cpp Mon Nov  3 18:56:30 2014
@@ -1306,13 +1306,11 @@ SBTarget::ReadMemory (const SBAddress ad
     if (target_sp)
     {
         Mutex::Locker api_locker (target_sp->GetAPIMutex());
-        lldb_private::Address addr_priv(addr.GetFileAddress(), NULL);
-        lldb_private::Error err_priv;    
-        bytes_read = target_sp->ReadMemory(addr_priv, false, buf, size, err_priv);
-        if(err_priv.Fail())
-        {
-            sb_error.SetError(err_priv.GetError(), err_priv.GetType());
-        }
+        bytes_read = target_sp->ReadMemory(addr.ref(), false, buf, size, sb_error.ref());
+    }
+    else
+    {
+        sb_error.SetErrorString("invalid target");
     }
 
     return bytes_read;

Modified: lldb/trunk/test/python_api/target/TestTargetAPI.py
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/test/python_api/target/TestTargetAPI.py?rev=221213&r1=221212&r2=221213&view=diff
==============================================================================
--- lldb/trunk/test/python_api/target/TestTargetAPI.py (original)
+++ lldb/trunk/test/python_api/target/TestTargetAPI.py Mon Nov  3 18:56:30 2014
@@ -213,16 +213,20 @@ class TargetAPITestCase(TestBase):
         breakpoint = target.BreakpointCreateByLocation("main.c", self.line_main)
         self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
+        # Put debugger into synchronous mode so when we target.LaunchSimple returns
+        # it will guaranteed to be at the breakpoint
+        self.dbg.SetAsync(False)
+        
         # Launch the process, and do not stop at the entry point.
         process = target.LaunchSimple (None, None, self.get_process_working_directory())
 
         # find the file address in the .data section of the main
         # module            
         data_section = self.find_data_section(target)
-        data_section_addr = data_section.file_addr
-        a = target.ResolveFileAddress(data_section_addr)
-
-        content = target.ReadMemory(a, 1, lldb.SBError())
+        sb_addr = lldb.SBAddress(data_section, 0)
+        error = lldb.SBError()
+        content = target.ReadMemory(sb_addr, 1, error)
+        self.assertTrue(error.Success(), "Make sure memory read succeeded")
         self.assertEquals(len(content), 1)
 
     def create_simple_target(self, fn):