Add control over debug location omission

Change-Id: I845e1ca877d7055b1a83defdae26b17c92064952

Author: jacek-galazka

IGC/Compiler/DebugInfo/VISADebugEmitter.cpp

@@ -318,14 +318,27 @@ void DebugEmitter::Finalize(void*& pBuffer, unsigned int& size, bool finalize)
                 }
             }
 
-            if (emptyLoc && prevSrcLoc && pFunc->getSubprogram())
+            if (emptyLoc && prevSrcLoc)
             {
-              auto scope = pFunc->getSubprogram();
+              if (IGC_IS_FLAG_ENABLED(FillMissingDebugLocations))
+              {
+                if (auto scope = pFunc->getSubprogram())
+                {
+                  auto src = m_pDwarfDebug->getOrCreateSourceID(scope->getFilename(), scope->getDirectory(), m_pStreamEmitter->GetDwarfCompileUnitID());
+
+                  // Emit func top as line# for unattributed lines
+                  m_pStreamEmitter->EmitDwarfLocDirective(src, scope->getLine(), 0, 0, 0, 0, scope->getFilename());          
+                }
+              } 
+              else
+              {
+                auto scope = prevSrcLoc->getScope();
                 auto src = m_pDwarfDebug->getOrCreateSourceID(scope->getFilename(), scope->getDirectory(), m_pStreamEmitter->GetDwarfCompileUnitID());
 
-                // TODO It is workaround to not emit empty lines until we figure out a proper solution
-                // Emit func top as line# for unattributed lines
-                m_pStreamEmitter->EmitDwarfLocDirective(src, scope->getLine(), 0, 0, 0, 0, scope->getFilename());
+                // Emit 0 as line# for unattributed lines
+                m_pStreamEmitter->EmitDwarfLocDirective(src, 0, 0, 0, 0, 0, scope->getFilename());   
+              }
+
                 prevSrcLoc = DebugLoc();
             }
         }

IGC/common/igc_flags.def

@@ -219,6 +219,7 @@ DECLARE_IGC_REGKEY(debugString, DisablePassToggles,     0,     "Disable each IGC
 DECLARE_IGC_REGKEY(bool, ForceStatelessForQueueT,       true,  "In OCL, force to use stateless memory to hold queue_t*. This is a legacy feature to be removed.", false)
 DECLARE_IGC_REGKEY(bool, ForceMemoryFenceBeforeEOT,     false, "Forces inserting SLM or gloabal memory fence before EOT if shader writes to SLM or goblam memory respectively.", false)
 DECLARE_IGC_REGKEY(bool, EnableRTmaskPso,               true,  "Enable render target mask optimization in PSO opt", false)
+DECLARE_IGC_REGKEY(bool, FillMissingDebugLocations,     true,  "Enable emiting function entry debug location for instruction that miss DL", false)
 
 DECLARE_IGC_GROUP("Shader dumping")
 DECLARE_IGC_REGKEY(bool, EnableCosDump, false, "Enable cos dump", true)