http://llvm.org/bugs/show_bug.cgi?id=11618

lldb::SBValue::AddressOf does not work on dereferenced registers in synthetic children provider

Patch submitted by Enrico Granata.

llvm-svn: 147637

6 files changed, 49 insertions, 8 deletions

diff --git a/lldb/include/lldb/Expression/ClangExpressionVariable.h b/lldb/include/lldb/Expression/ClangExpressionVariable.h
index 1a0e540a269..00897265130 100644
--- a/lldb/include/lldb/Expression/ClangExpressionVariable.h
+++ b/lldb/include/lldb/Expression/ClangExpressionVariable.h
@@ -206,6 +206,15 @@ public:
 
     void
     ValueUpdated ();
+    
+    // this function is used to copy the address-of m_live_sp into m_frozen_sp
+    // this is necessary because the results of certain cast and pointer-arithmetic
+    // operations (such as those described in bugzilla issues 11588 and 11618) generate
+    // frozen objcts that do not have a valid address-of, which can be troublesome when
+    // using synthetic children providers. transferring the address-of the live object
+    // solves these issues and provides the expected user-level behavior
+    void
+    TransferAddress (bool force = false);
 
     typedef lldb::SharedPtr<ValueObjectConstResult>::Type ValueObjectConstResultSP;
 
diff --git a/lldb/source/Expression/ClangExpressionDeclMap.cpp b/lldb/source/Expression/ClangExpressionDeclMap.cpp
index e115054549a..128db9c5753 100644
--- a/lldb/source/Expression/ClangExpressionDeclMap.cpp
+++ b/lldb/source/Expression/ClangExpressionDeclMap.cpp
@@ -406,13 +406,6 @@ ClangExpressionDeclMap::CompleteResultVariable (lldb::ClangExpressionVariableSP
                                                             address,
                                                             address_type,
                                                             pvar_sp->GetByteSize());
-        
-        // if the frozen object does not yet have a valid live address we replicate the live_sp address
-        // to it. this solves the issue where synthetic children providers are unable to access
-        // the address-of result for objects obtained by casting the result of pointer arithmetic
-        // performed by the expression parser, as in: print *((ClassType*)(value-1))
-        if (pvar_sp->m_frozen_sp->GetLiveAddress() == LLDB_INVALID_ADDRESS)
-            pvar_sp->m_frozen_sp->SetLiveAddress(address);
     }
     
     if (pvar_sp->m_flags & ClangExpressionVariable::EVNeedsFreezeDry)
diff --git a/lldb/source/Expression/ClangExpressionParser.cpp b/lldb/source/Expression/ClangExpressionParser.cpp
index 912822399dc..7c3e6589621 100644
--- a/lldb/source/Expression/ClangExpressionParser.cpp
+++ b/lldb/source/Expression/ClangExpressionParser.cpp
@@ -500,6 +500,8 @@ ClangExpressionParser::PrepareForExecution (lldb::addr_t &func_allocation_addr,
         
         if (execution_policy != eExecutionPolicyAlways && ir_for_target.interpretSuccess())
         {
+            if (const_result)
+                const_result->TransferAddress();
             evaluated_statically = true;
             err.Clear();
             return err;
diff --git a/lldb/source/Expression/ClangExpressionVariable.cpp b/lldb/source/Expression/ClangExpressionVariable.cpp
index 9a264eba062..ec08a0c0af3 100644
--- a/lldb/source/Expression/ClangExpressionVariable.cpp
+++ b/lldb/source/Expression/ClangExpressionVariable.cpp
@@ -133,3 +133,15 @@ ClangExpressionVariable::ValueUpdated ()
     m_frozen_sp->ValueUpdated ();
 }
 
+void
+ClangExpressionVariable::TransferAddress (bool force)
+{
+    if (m_live_sp.get() == NULL)
+        return;
+
+    if (m_frozen_sp.get() == NULL)
+        return;
+    
+    if (force || (m_frozen_sp->GetLiveAddress() == LLDB_INVALID_ADDRESS))
+        m_frozen_sp->SetLiveAddress(m_live_sp->GetLiveAddress());
+}
diff --git a/lldb/source/Expression/ClangUserExpression.cpp b/lldb/source/Expression/ClangUserExpression.cpp
index c2164c80037..7719f081518 100644
--- a/lldb/source/Expression/ClangUserExpression.cpp
+++ b/lldb/source/Expression/ClangUserExpression.cpp
@@ -525,6 +525,9 @@ ClangUserExpression::FinalizeJITExecution (Stream &error_stream,
         return false;
     }
     
+    if (result)
+        result->TransferAddress();
+    
     return true;
 }        
 
diff --git a/lldb/test/expression_command/issue_11588/Test11588.py b/lldb/test/expression_command/issue_11588/Test11588.py
index ba0c1c622db..ab47281db07 100644
--- a/lldb/test/expression_command/issue_11588/Test11588.py
+++ b/lldb/test/expression_command/issue_11588/Test11588.py
@@ -42,11 +42,33 @@ class Issue11581TestCase(TestBase):
 
         self.expect("print *((StgClosure*)(r14-1))",
             substrs = ["(StgClosure) $",
-            "(StgClosure *) &$0 = 0x",
+            "(StgClosure *) &$","0x",
             "(long) addr = ",
             "(long) load_address = "])
 
 
+        target = lldb.debugger.GetSelectedTarget()
+        process = target.GetProcess()
+# register r14 does not exist on 32-bit architectures, it is an x86_64 extension
+# let's skip this part of the test if we are in 32-bit mode
+        if process.GetAddressByteSize() == 8:
+                frame = process.GetSelectedThread().GetSelectedFrame()
+                pointer = frame.FindVariable("r14")
+                addr = pointer.GetValueAsUnsigned(0)
+                self.assertTrue(addr != 0, "could not read pointer to StgClosure")
+                addr = addr - 1
+                self.runCmd("register write r14 %d" % addr)
+                self.expect("register read r14",
+                    substrs = ["0x",hex(addr)[2:]])
+                self.expect("print *(StgClosure*)$r14",
+                    substrs = ["(StgClosure) $",
+                    "(StgClosure *) &$","0x",
+                    "(long) addr = ",
+                    "(long) load_address = ",
+                    hex(addr)[2:],
+                    str(addr)])
+
+
 if __name__ == '__main__':
     import atexit
     lldb.SBDebugger.Initialize()