gpu-compute: fix segfault when constructing GPUExecContext

the GPUExecContext context currently stores a reference to its parent WF's
GPUISA object, however there are some special instructions that do not have
an associated WF. when these objects are constructed they set their WF pointer
to null, which causes the GPUExecContext to segfault when trying to
dereference
the WF pointer to get at the WF's GPUISA object. here we change the GPUISA
reference in the GPUExecContext class to a pointer so that it may be set to
null.

diff --git a/src/gpu-compute/gpu_exec_context.cc b/src/gpu-compute/gpu_exec_context.cc
index ca694187c55fc34bbb48415a91d9bdbf4eab1dde..c39bec392c85bec9de45f5712e3b9bb36fa2f719 100644 (file)
--- a/src/gpu-compute/gpu_exec_context.cc
+++ b/src/gpu-compute/gpu_exec_context.cc
@@ -37,7 +37,7 @@
 #include "gpu-compute/wavefront.hh"
 
 GPUExecContext::GPUExecContext(ComputeUnit *_cu, Wavefront *_wf)
-    : cu(_cu), wf(_wf), gpuISA(_wf->gpuISA())
+    : cu(_cu), wf(_wf), gpuISA(_wf ? &_wf->gpuISA() : nullptr)
 {
 }
 
@@ -56,11 +56,13 @@ GPUExecContext::wavefront()
 TheGpuISA::MiscReg
 GPUExecContext::readMiscReg(int opIdx) const
 {
-    return gpuISA.readMiscReg(opIdx);
+    assert(gpuISA);
+    return gpuISA->readMiscReg(opIdx);
 }
 
 void
 GPUExecContext::writeMiscReg(int opIdx, TheGpuISA::MiscReg operandVal)
 {
-    gpuISA.writeMiscReg(opIdx, operandVal);
+    assert(gpuISA);
+    gpuISA->writeMiscReg(opIdx, operandVal);
 }

diff --git a/src/gpu-compute/gpu_exec_context.hh b/src/gpu-compute/gpu_exec_context.hh
index f7c021c0db96fee33f818124189be8271b48f817..513a0615137c14f131f291340a2ce04296ad959b 100644 (file)
--- a/src/gpu-compute/gpu_exec_context.hh
+++ b/src/gpu-compute/gpu_exec_context.hh
@@ -55,7 +55,7 @@ class GPUExecContext
   protected:
     ComputeUnit *cu;
     Wavefront *wf;
-    TheGpuISA::GPUISA &gpuISA;
+    TheGpuISA::GPUISA *gpuISA;
 };
 
 #endif // __GPU_EXEC_CONTEXT_HH__