Fix stack-use-after-scope crash in conversions (#1358)

The way that program sources were being constructed involved capturing
pointers to strings that were allocated on the stack, and then trying
to use them outside of that scope. This change uses a stringstream
defined in the outer scope to build the program instead.

test_conformance/conversions/test_conversions.cpp

@@ -38,6 +38,7 @@
 #include <sys/param.h>
 #endif
 
+#include <sstream>
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
@@ -1559,84 +1560,40 @@ static cl_program   MakeProgram( Type outType, Type inType, SaturationMode sat,
     cl_program program;
     char testName[256];
     int error = 0;
-    const char **strings;
+
-    size_t stringCount = 0;
+    std::ostringstream source;
+    if (outType == kdouble || inType == kdouble)
+        source << "#pragma OPENCL EXTENSION cl_khr_fp64 : enable\n";
 
     // Create the program. This is a bit complicated because we are trying to avoid byte and short stores.
     if (0 == vectorSize)
     {
+        // Create the type names.
         char inName[32];
         char outName[32];
-        const char *programSource[] =
-        {
-            "", // optional pragma
-            "__kernel void ", testName, "( __global ", inName, " *src, __global ", outName, " *dest )\n"
-            "{\n"
-            "   size_t i = get_global_id(0);\n"
-            "   dest[i] =  src[i];\n"
-            "}\n"
-        };
-        stringCount = sizeof(programSource) / sizeof(programSource[0]);
-        strings = programSource;
-
-        if (outType == kdouble || inType == kdouble)
-            programSource[0] = "#pragma OPENCL EXTENSION cl_khr_fp64 : enable\n";
-
-        //create the type name
         strncpy(inName, gTypeNames[inType], sizeof(inName));
         strncpy(outName, gTypeNames[outType], sizeof(outName));
         sprintf(testName, "test_implicit_%s_%s", outName, inName);
-        vlog("Building implicit %s -> %s conversion test\n", gTypeNames[inType], gTypeNames[outType]);
+
+        source << "__kernel void " << testName << "( __global " << inName
+               << " *src, __global " << outName << " *dest )\n";
+        source << "{\n";
+        source << "   size_t i = get_global_id(0);\n";
+        source << "   dest[i] =  src[i];\n";
+        source << "}\n";
+
+        vlog("Building implicit %s -> %s conversion test\n", gTypeNames[inType],
+             gTypeNames[outType]);
         fflush(stdout);
     }
     else
     {
         int vectorSizetmp = vectorSizes[vectorSize];
 
+        // Create the type names.
         char convertString[128];
         char inName[32];
         char outName[32];
-        const char *programSource[] =
-        {
-            "", // optional pragma
-            "__kernel void ", testName, "( __global ", inName, " *src, __global ", outName, " *dest )\n"
-            "{\n"
-            "   size_t i = get_global_id(0);\n"
-            "   dest[i] = ", convertString, "( src[i] );\n"
-            "}\n"
-        };
-        const char *programSourceV3[] =
-        {
-            "", // optional pragma
-            "__kernel void ", testName, "( __global ", inName, " *src, __global ", outName, " *dest )\n"
-            "{\n"
-            "   size_t i = get_global_id(0);\n"
-            "   if( i + 1 < get_global_size(0))\n"
-            "       vstore3( ", convertString, "( vload3( i, src)), i, dest );\n"
-            "   else\n"
-            "   {\n"
-            "       ", inName, "3 in;\n"
-            "       ", outName, "3 out;\n"
-            "       if( 0 == (i & 1) )\n"
-            "           in.y = src[3*i+1];\n"
-            "       in.x = src[3*i];\n"
-            "       out = ", convertString, "( in ); \n"
-            "       dest[3*i] = out.x;\n"
-            "       if( 0 == (i & 1) )\n"
-            "           dest[3*i+1] = out.y;\n"
-            "   }\n"
-            "}\n"
-        };
-        stringCount = 3 == vectorSizetmp ? sizeof(programSourceV3) / sizeof(programSourceV3[0]) :
-            sizeof(programSource) / sizeof(programSource[0]);
-        strings = 3 == vectorSizetmp ? programSourceV3 : programSource;
-
-        if (outType == kdouble || inType == kdouble) {
-            programSource[0] = "#pragma OPENCL EXTENSION cl_khr_fp64 : enable\n";
-            programSourceV3[0] = "#pragma OPENCL EXTENSION cl_khr_fp64 : enable\n";
-        }
-
-        //create the type name
         switch (vectorSizetmp)
         {
         case 1:
@@ -1661,8 +1618,40 @@ static cl_program   MakeProgram( Type outType, Type inType, SaturationMode sat,
             vlog("Building %s( %s ) test\n", convertString, inName);
             break;
         }
-
         fflush(stdout);
+
+        if (vectorSizetmp == 3)
+        {
+            source << "__kernel void " << testName << "( __global " << inName
+                   << " *src, __global " << outName << " *dest )\n";
+            source << "{\n";
+            source << "   size_t i = get_global_id(0);\n";
+            source << "   if( i + 1 < get_global_size(0))\n";
+            source << "       vstore3( " << convertString
+                   << "( vload3( i, src)), i, dest );\n";
+            source << "   else\n";
+            source << "   {\n";
+            source << "       " << inName << "3 in;\n";
+            source << "       " << outName << "3 out;\n";
+            source << "       if( 0 == (i & 1) )\n";
+            source << "           in.y = src[3*i+1];\n";
+            source << "       in.x = src[3*i];\n";
+            source << "       out = " << convertString << "( in ); \n";
+            source << "       dest[3*i] = out.x;\n";
+            source << "       if( 0 == (i & 1) )\n";
+            source << "           dest[3*i+1] = out.y;\n";
+            source << "   }\n";
+            source << "}\n";
+        }
+        else
+        {
+            source << "__kernel void " << testName << "( __global " << inName
+                   << " *src, __global " << outName << " *dest )\n";
+            source << "{\n";
+            source << "   size_t i = get_global_id(0);\n";
+            source << "   dest[i] = " << convertString << "( src[i] );\n";
+            source << "}\n";
+        }
     }
     *outKernel = NULL;
 
@@ -1671,7 +1660,10 @@ static cl_program   MakeProgram( Type outType, Type inType, SaturationMode sat,
         flags = "-cl-denorms-are-zero";
 
     // build it
-    error = create_single_kernel_helper(gContext, &program, outKernel, (cl_uint)stringCount, strings, testName, flags);
+    std::string sourceString = source.str();
+    const char *programSource = sourceString.c_str();
+    error = create_single_kernel_helper(gContext, &program, outKernel, 1,
+                                        &programSource, testName, flags);
     if (error)
     {
         char    buffer[2048] = "";