Updated context management logic:

1) hipSetDevice sets a flag so that next call to hipCtxGetCurrent returns primary context on current device
2) hipCtxGetCurrent returns primary context on current device if TLS context stack is empty
3) hipCtxPopCurrent falls back to primary context on current device as default
4) hipCtxPushCurrent, hipCtxSetCurrent and hipCtxCreate reset the flag set in hipSetDevice


[ROCm/hip commit: 3e84cf4aba]

projects/hip/src/hip_context.cpp

@@ -31,6 +31,7 @@ THE SOFTWARE.
 
 // Stack of contexts
 thread_local std::stack<ihipCtx_t *>  tls_ctxStack;
+thread_local bool tls_getPrimaryCtx = true;
 
 void ihipCtxStackUpdate()
 {
@@ -65,6 +66,7 @@ hipError_t hipCtxCreate(hipCtx_t *ctx, unsigned int flags,  hipDevice_t device)
 		*ctx = ictx;
 		ihipSetTlsDefaultCtx(*ctx);
 		tls_ctxStack.push(*ctx);
+        tls_getPrimaryCtx = false;
 		deviceCrit->addContext(ictx);
     }
 
@@ -93,8 +95,7 @@ hipError_t hipDriverGetVersion(int *driverVersion)
     hipError_t e = hipSuccess;
     if (driverVersion) {
         *driverVersion = 4;
-    }
-    else {
+    } else {
         e = hipErrorInvalidValue;
     }
 
@@ -107,8 +108,7 @@ hipError_t hipRuntimeGetVersion(int *runtimeVersion)
     hipError_t e = hipSuccess;
     if (runtimeVersion) {
         *runtimeVersion = HIP_VERSION_PATCH;
-    }
-    else {
+    } else {
         e = hipErrorInvalidValue;
     }
 
@@ -124,9 +124,7 @@ hipError_t hipCtxDestroy(hipCtx_t ctx)
     if(primaryCtx== ctx)
     {
         e = hipErrorInvalidValue;
-    }
-    else
-    {
+    } else {
         if(currentCtx == ctx) {
             //need to destroy the ctx associated with calling thread
             tls_ctxStack.pop();
@@ -146,19 +144,21 @@ hipError_t hipCtxPopCurrent(hipCtx_t* ctx)
 {
     HIP_INIT_API(ctx);
     hipError_t e = hipSuccess;
-    ihipCtx_t* tempCtx;
-    *ctx = ihipGetTlsDefaultCtx();
+    ihipCtx_t* currentCtx = ihipGetTlsDefaultCtx();
+    auto deviceHandle = currentCtx->getDevice();
+    *ctx = currentCtx;
+
     if(!tls_ctxStack.empty()) {
         tls_ctxStack.pop();
     }
+
     if(!tls_ctxStack.empty()) {
-        tempCtx= tls_ctxStack.top();
-    }
-    else {
-        tempCtx = nullptr;
+        currentCtx= tls_ctxStack.top();
+    } else {
+        currentCtx = deviceHandle->_primaryCtx;
     }
 
-    ihipSetTlsDefaultCtx(tempCtx); //TOD0 - Shall check for NULL?
+    ihipSetTlsDefaultCtx(currentCtx); //TOD0 - Shall check for NULL?
     return ihipLogStatus(e);
 }
 
@@ -169,8 +169,8 @@ hipError_t hipCtxPushCurrent(hipCtx_t ctx)
     if(ctx != NULL) {    //TODO- is this check needed?
         ihipSetTlsDefaultCtx(ctx);
         tls_ctxStack.push(ctx);
-    }
-    else {
+        tls_getPrimaryCtx = false;
+    } else {
         e = hipErrorInvalidContext;
     }
     return ihipLogStatus(e);
@@ -180,12 +180,11 @@ hipError_t hipCtxGetCurrent(hipCtx_t* ctx)
 {
     HIP_INIT_API(ctx);
     hipError_t e = hipSuccess;
-    if(!tls_ctxStack.empty()) {
+    if((tls_getPrimaryCtx) || tls_ctxStack.empty()) {
+        *ctx = ihipGetTlsDefaultCtx();
+    } else {
         *ctx= tls_ctxStack.top();
     }
-    else {
-        *ctx = NULL;
-    }
     return ihipLogStatus(e);
 }
 
@@ -195,10 +194,10 @@ hipError_t hipCtxSetCurrent(hipCtx_t ctx)
     hipError_t e = hipSuccess;
     if(ctx == NULL) {
         tls_ctxStack.pop();
-    }
-    else {
+    } else {
         ihipSetTlsDefaultCtx(ctx);
         tls_ctxStack.push(ctx);
+        tls_getPrimaryCtx = false;
     }
     return ihipLogStatus(e);
 }
@@ -213,8 +212,7 @@ hipError_t hipCtxGetDevice(hipDevice_t *device)
     if(ctx == nullptr) {
         e = hipErrorInvalidContext;
         // TODO *device = nullptr;
-    }
-    else {
+    } else {
         auto deviceHandle = ctx->getDevice();
         *device = deviceHandle->_deviceId;
     }

projects/hip/src/hip_device.cpp

@@ -146,6 +146,7 @@ hipError_t hipSetDevice(int deviceId)
         return ihipLogStatus(hipErrorInvalidDevice);
     } else {
         ihipSetTlsDefaultCtx(ihipGetPrimaryCtx(deviceId));
+        tls_getPrimaryCtx = true;
         return ihipLogStatus(hipSuccess);
     }
 }

projects/hip/src/hip_hcc_internal.h

@@ -114,6 +114,7 @@ private:
 //Extern tls
 extern thread_local hipError_t tls_lastHipError;
 extern thread_local TidInfo tls_tidInfo;
+extern thread_local bool tls_getPrimaryCtx;
 
 extern std::vector<ProfTrigger> g_dbStartTriggers;
 extern std::vector<ProfTrigger> g_dbStopTriggers;