BUGFIX: Static timing analysis no longer goes into infinite recursion when we have a combinatorial loop. Report combinatorial loops as PAR warnings. Skip timing analysis if we have no timing data file. Reduced warning spam when timing data is incomplete from one message per path to one message total

azonenberg · azonenberg · commit 48edca9452d9 · 2017-06-09T09:05:26.000-07:00
diff --git a/src/gp4par/par_reporting.cpp b/src/gp4par/par_reporting.cpp
@@ -247,6 +247,12 @@ void PrintPlacementReport(PARGraph* netlist, Greenpak4Device* /*device*/)
  */
 void PrintTimingReport(Greenpak4Netlist* netlist, Greenpak4Device* device)
 {
+	if(!device->HasTimingData())
+	{
+		LogWarning("No timing data for target device, not running timing analysis\n");
+		return;
+	}
+
 	LogNotice("\nTiming report:\n");
 	LogIndenter li;
 
@@ -287,6 +293,7 @@ void PrintTimingReport(Greenpak4Netlist* netlist, Greenpak4Device* device)
 
 	//DEBUG: print all paths
 	int i=0;
+	bool incomplete = false;
 	for(auto path : paths)
 	{
 		LogVerbose("Path %d\n", i++);
@@ -330,8 +337,9 @@ void PrintTimingReport(Greenpak4Netlist* netlist, Greenpak4Device* device)
 					auto rscell = device->GetIOB(3);
 					if(!rscell->GetCombinatorialDelay(previous_port, edge->m_sourceport, corner, delay))
 					{
-						LogWarning("Couldn't get timing data even from fallback pin\n");
-						delay = CombinatorialDelay(0, 0);
+						//LogWarning("Couldn't get timing data even from fallback pin\n");
+						incomplete = true;
+						continue;
 					}
 				}
 
@@ -356,8 +364,9 @@ void PrintTimingReport(Greenpak4Netlist* netlist, Greenpak4Device* device)
 			CombinatorialDelay delay;
 			if(!srccell->GetCombinatorialDelay(previous_port, edge->m_sourceport, corner, delay))
 			{
-				LogWarning("Couldn't get timing data\n");
-				delay = CombinatorialDelay(0, 0);
+				//LogWarning("Couldn't get timing data\n");
+				incomplete = true;
+				continue;
 			}
 			float worst = delay.GetWorst();
 			cdelay += worst;
@@ -381,8 +390,9 @@ void PrintTimingReport(Greenpak4Netlist* netlist, Greenpak4Device* device)
 			{
 				if(!xc->GetCombinatorialDelay("I", "O", corner, delay))
 				{
-					LogWarning("Couldn't get timing data\n");
-					delay = CombinatorialDelay(0, 0);
+					//LogWarning("Couldn't get timing data\n");
+					incomplete = true;
+					continue;
 				}
 				float worst = delay.GetWorst();
 				cdelay += worst;
@@ -410,8 +420,9 @@ void PrintTimingReport(Greenpak4Netlist* netlist, Greenpak4Device* device)
 					auto rscell = device->GetIOB(3);
 					if(!rscell->GetCombinatorialDelay(edge->m_destport, "IO", corner, delay))
 					{
-						LogWarning("Couldn't get timing data even from fallback pin\n");
-						delay = CombinatorialDelay(0, 0);
+						//LogWarning("Couldn't get timing data even from fallback pin\n");
+						incomplete = true;
+						continue;
 					}
 				}
 
@@ -432,6 +443,8 @@ void PrintTimingReport(Greenpak4Netlist* netlist, Greenpak4Device* device)
 			"+--------------------------------------------------------------+------------+-----------"
 			"+------------+------------+------------+\n");
 	}
+	if(incomplete)
+		LogWarning("Timing data doesn't have info for all primitives, report is incomplete\n");
 }
 
 /**
@@ -495,6 +508,34 @@ void FindCombinatorialPaths(
 	{
 		auto edge = destnode->GetEdgeByIndex(i);
 
+		//Verify that this edge is not already in the netlist. If it is, complain and stop
+		bool loop = false;
+		for(auto tedge : basepath)
+		{
+			if(edge == tedge)
+			{
+				loop = true;
+
+				LogWarning("Found combinatorial loop, not following it for static timing\n");
+				LogIndenter li;
+
+				for(auto eedge : basepath)
+				{
+					auto snode = static_cast<Greenpak4NetlistEntity*>(eedge->m_sourcenode->GetData());
+					auto dnode = static_cast<Greenpak4NetlistEntity*>(eedge->m_destnode->GetData());
+					LogWarning("From cell %50s port %15s to %50s port %15s\n",
+						snode->m_name.c_str(),
+						eedge->m_sourceport.c_str(),
+						dnode->m_name.c_str(),
+						eedge->m_destport.c_str());
+				}
+
+				break;
+			}
+		}
+		if(loop)
+			continue;
+
 		//Find all paths that begin with the new, longer path
 		CombinatorialPath npath = basepath;
 		npath.push_back(edge);
diff --git a/src/greenpak4/Greenpak4Device.cpp b/src/greenpak4/Greenpak4Device.cpp
@@ -34,6 +34,7 @@ Greenpak4Device::Greenpak4Device(
 	, m_disableChargePump(false)
 	, m_ldoBypass(false)
 	, m_nvmLoadRetryCount(1)
+	, m_hasTimingData(false)
 {
 	//Create power rails
 	//These have to come first, since all other nodes will refer to these during construction
@@ -1413,5 +1414,7 @@ bool Greenpak4Device::LoadTimingData(json_object* object)
 			return false;
 	}
 
+	m_hasTimingData = true;
+
 	return true;
 }
diff --git a/src/greenpak4/Greenpak4Device.h b/src/greenpak4/Greenpak4Device.h
@@ -336,6 +336,9 @@ class Greenpak4Device
 	bool LoadTimingData(json_object* object);
 	bool LoadTimingData(std::string fname);
 
+	bool HasTimingData()
+	{ return m_hasTimingData; }
+
 protected:
 
 	bool GenerateBitstream(bool* bitstream, uint8_t userid, bool readProtect);
@@ -496,6 +499,11 @@ class Greenpak4Device
 		@brief Number of times to attempt re-reading NVM in case of boot failure
 	 */
 	int m_nvmLoadRetryCount;
+
+	/**
+		@brief True if we have static timing data
+	 */
+	bool m_hasTimingData;
 };
 
 #endif

Original file line number	Diff line number	Diff line change
`@@ -34,6 +34,7 @@ Greenpak4Device::Greenpak4Device(`
`34`	`34`	`, m_disableChargePump(false)`
`35`	`35`	`, m_ldoBypass(false)`
`36`	`36`	`, m_nvmLoadRetryCount(1)`
	`37`	`+ , m_hasTimingData(false)`
`37`	`38`	`{`
`38`	`39`	`//Create power rails`
`39`	`40`	`//These have to come first, since all other nodes will refer to these during construction`
`@@ -1413,5 +1414,7 @@ bool Greenpak4Device::LoadTimingData(json_object* object)`
`1413`	`1414`	`return false;`
`1414`	`1415`	`}`
`1415`	`1416`
	`1417`	`+ m_hasTimingData = true;`
	`1418`	`+`
`1416`	`1419`	`return true;`
`1417`	`1420`	`}`