From 1efa0a42f6a490bfb88cfd928c53d17c3dd62907 Mon Sep 17 00:00:00 2001
From: Rene Gollent <anevilyak@gmail.com>
Date: Tue, 26 Mar 2013 18:48:22 -0400
Subject: [PATCH] Fix return value handling.

- In the case of position independent code, the initial call isn't to
  the function we want, but rather to a PLT slot which resolves the
  function's location. As such, find that slot and use it to determine
  the corresponding GOT offset for the function's real location.

Still need some further refactoring of return value handling to properly
handle the case of stepping over a single line that makes multiple calls,
but this fixes the basic case at least.
---
 .../debug_info/DwarfImageDebugInfo.cpp        | 31 +++++++++++++------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/src/apps/debugger/debug_info/DwarfImageDebugInfo.cpp b/src/apps/debugger/debug_info/DwarfImageDebugInfo.cpp
index 4c0247fb66..0195eccae4 100644
--- a/src/apps/debugger/debug_info/DwarfImageDebugInfo.cpp
+++ b/src/apps/debugger/debug_info/DwarfImageDebugInfo.cpp
@@ -674,14 +674,10 @@ DwarfImageDebugInfo::CreateFrame(Image* image,
 			instructionPointer, functionInstance->Address() - fRelocationDelta,
 			subprogramEntry->Variables(), subprogramEntry->Blocks());
 
-		// TODO: re-enable once PIC and false positive issues
-		// are properly dealt with
-#if 0
 		if (returnFunctionAddress != 0) {
-			_CreateReturnValue(returnFunctionAddress, image, frame,
-				*stackFrameDebugInfo);
+			_CreateReturnValue(returnFunctionAddress, returnFunctionState,
+				image, frame, *stackFrameDebugInfo);
 		}
-#endif
 	}
 
 	_frame = frameReference.Detach();
@@ -1104,15 +1100,30 @@ DwarfImageDebugInfo::_CreateReturnValue(target_addr_t returnFunctionAddress,
 	}
 
 	status_t result = B_OK;
+	ImageDebugInfo* imageInfo = image->GetImageDebugInfo();
 	FunctionInstance* targetFunction;
 	if (returnFunctionAddress >= fPLTSectionStart
 		&& returnFunctionAddress < fPLTSectionEnd) {
-		// TODO: handle resolving PLT entries
-		// to their target function
-		return B_UNSUPPORTED;
+		// if the function in question is position-independent, the call
+		// will actually have taken us to its corresponding PLT slot.
+		// in such a case, look at the disassembled jump to determine
+		// where to find the actual function address.
+		InstructionInfo info;
+		if (fDebuggerInterface->GetArchitecture()->GetInstructionInfo(
+			returnFunctionAddress, info, returnFunctionState) != B_OK) {
+			return B_BAD_VALUE;
+		}
+
+		target_size_t addressSize = fDebuggerInterface->GetArchitecture()
+			->AddressSize();
+		ssize_t bytesRead = fDebuggerInterface->ReadMemory(info.TargetAddress(),
+			&returnFunctionAddress, addressSize);
+
+		if (bytesRead != addressSize)
+			return B_BAD_VALUE;
 	}
 
-	ImageDebugInfo* imageInfo = image->GetImageDebugInfo();
+
 	targetFunction = imageInfo->FunctionAtAddress(returnFunctionAddress);
 	if (targetFunction != NULL) {
 		DwarfFunctionDebugInfo* targetInfo =