Initialize destinations variables before calling GL functions

because if the context is lost those variables will
be uninitialized.

TEST=ran chrome, conformance tests, unit tests and hand edited gles2_demo to test
BUG=none

Review URL: http://codereview.chromium.org/5305005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@67293 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 52 insertions, 2 deletions

diff --git a/gpu/command_buffer/client/gles2_c_lib.cc b/gpu/command_buffer/client/gles2_c_lib.cc
index 74cc431..f53067e 100644
--- a/gpu/command_buffer/client/gles2_c_lib.cc
+++ b/gpu/command_buffer/client/gles2_c_lib.cc
@@ -4,8 +4,36 @@
 
 // These functions emluate GLES2 over command buffers for C.
 
+#include <assert.h>
 #include "../client/gles2_lib.h"
 
+// Check that destination pointers point to initialized memory.
+// When the context is lost, calling GL function has no effect so if destination
+// pointers point to initialized memory it can often lead to crash bugs. eg.
+//
+// GLsizei len;
+// glGetShaderSource(shader, max_size, &len, buffer);
+// std::string src(buffer, buffer + len);  // len can be uninitialized here!!!
+//
+// Because this check is not official GL this check happens only on Chrome code,
+// not Pepper.
+//
+// If it was up to us we'd just always write to the destination but the OpenGL
+// spec defines the behavior of OpenGL function, not us. :-(
+#if defined(__native_client__)
+  #define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v)
+#elif defined(GPU_DCHECK)
+  #define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v) GPU_DCHECK(v)
+#elif defined(DCHECK)
+  #define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v) DCHECK(v)
+#else
+  #define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(v) ASSERT(v)
+#endif
+
+#define GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(type, ptr) \
+    GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION_ASSERT(ptr && \
+        (ptr[0] == static_cast<type>(0) || ptr[0] == static_cast<type>(-1)));
+
 extern "C" {
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
diff --git a/gpu/command_buffer/client/gles2_c_lib_autogen.h b/gpu/command_buffer/client/gles2_c_lib_autogen.h
index ab54997..420b0e5 100644
--- a/gpu/command_buffer/client/gles2_c_lib_autogen.h
+++ b/gpu/command_buffer/client/gles2_c_lib_autogen.h
@@ -279,6 +279,9 @@ void GLES2GenTextures(GLsizei n, GLuint* textures) {
 void GLES2GetActiveAttrib(
     GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
     GLenum* type, char* name) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLsizei, length);
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, size);
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLenum, type);
   GPU_CLIENT_LOG(
       "GetActiveAttrib" << "(" << program << ", " << index << ", " << bufsize << ", " << length << ", " << size << ", " << type << ", " << name << ")");  // NOLINT
   gles2::GetGLContext()->GetActiveAttrib(
@@ -287,6 +290,9 @@ void GLES2GetActiveAttrib(
 void GLES2GetActiveUniform(
     GLuint program, GLuint index, GLsizei bufsize, GLsizei* length, GLint* size,
     GLenum* type, char* name) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLsizei, length);
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, size);
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLenum, type);
   GPU_CLIENT_LOG(
       "GetActiveUniform" << "(" << program << ", " << index << ", " << bufsize << ", " << length << ", " << size << ", " << type << ", " << name << ")");  // NOLINT
   gles2::GetGLContext()->GetActiveUniform(
@@ -294,6 +300,7 @@ void GLES2GetActiveUniform(
 }
 void GLES2GetAttachedShaders(
     GLuint program, GLsizei maxcount, GLsizei* count, GLuint* shaders) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLsizei, count);
   GPU_CLIENT_LOG(
       "GetAttachedShaders" << "(" << program << ", " << maxcount << ", " << count << ", " << shaders << ")");  // NOLINT
   gles2::GetGLContext()->GetAttachedShaders(program, maxcount, count, shaders);
@@ -305,10 +312,12 @@ GLint GLES2GetAttribLocation(GLuint program, const char* name) {
   return result;
 }
 void GLES2GetBooleanv(GLenum pname, GLboolean* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLboolean, params);
   GPU_CLIENT_LOG("GetBooleanv" << "(" << pname << ", " << params << ")");
   gles2::GetGLContext()->GetBooleanv(pname, params);
 }
 void GLES2GetBufferParameteriv(GLenum target, GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetBufferParameteriv" << "(" << target << ", " << pname << ", " << params << ")");  // NOLINT
   gles2::GetGLContext()->GetBufferParameteriv(target, pname, params);
@@ -325,45 +334,54 @@ void GLES2GetFloatv(GLenum pname, GLfloat* params) {
 }
 void GLES2GetFramebufferAttachmentParameteriv(
     GLenum target, GLenum attachment, GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetFramebufferAttachmentParameteriv" << "(" << target << ", " << attachment << ", " << pname << ", " << params << ")");  // NOLINT
   gles2::GetGLContext()->GetFramebufferAttachmentParameteriv(
       target, attachment, pname, params);
 }
 void GLES2GetIntegerv(GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG("GetIntegerv" << "(" << pname << ", " << params << ")");
   gles2::GetGLContext()->GetIntegerv(pname, params);
 }
 void GLES2GetProgramiv(GLuint program, GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetProgramiv" << "(" << program << ", " << pname << ", " << params << ")");  // NOLINT
   gles2::GetGLContext()->GetProgramiv(program, pname, params);
 }
 void GLES2GetProgramInfoLog(
     GLuint program, GLsizei bufsize, GLsizei* length, char* infolog) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLsizei, length);
   GPU_CLIENT_LOG(
       "GetProgramInfoLog" << "(" << program << ", " << bufsize << ", " << length << ", " << infolog << ")");  // NOLINT
   gles2::GetGLContext()->GetProgramInfoLog(program, bufsize, length, infolog);
 }
 void GLES2GetRenderbufferParameteriv(
     GLenum target, GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetRenderbufferParameteriv" << "(" << target << ", " << pname << ", " << params << ")");  // NOLINT
   gles2::GetGLContext()->GetRenderbufferParameteriv(target, pname, params);
 }
 void GLES2GetShaderiv(GLuint shader, GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetShaderiv" << "(" << shader << ", " << pname << ", " << params << ")");
   gles2::GetGLContext()->GetShaderiv(shader, pname, params);
 }
 void GLES2GetShaderInfoLog(
     GLuint shader, GLsizei bufsize, GLsizei* length, char* infolog) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLsizei, length);
   GPU_CLIENT_LOG(
       "GetShaderInfoLog" << "(" << shader << ", " << bufsize << ", " << length << ", " << infolog << ")");  // NOLINT
   gles2::GetGLContext()->GetShaderInfoLog(shader, bufsize, length, infolog);
 }
 void GLES2GetShaderPrecisionFormat(
     GLenum shadertype, GLenum precisiontype, GLint* range, GLint* precision) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, range);
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, precision);
   GPU_CLIENT_LOG(
       "GetShaderPrecisionFormat" << "(" << shadertype << ", " << precisiontype << ", " << range << ", " << precision << ")");  // NOLINT
   gles2::GetGLContext()->GetShaderPrecisionFormat(
@@ -371,6 +389,7 @@ void GLES2GetShaderPrecisionFormat(
 }
 void GLES2GetShaderSource(
     GLuint shader, GLsizei bufsize, GLsizei* length, char* source) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLsizei, length);
   GPU_CLIENT_LOG(
       "GetShaderSource" << "(" << shader << ", " << bufsize << ", " << length << ", " << source << ")");  // NOLINT
   gles2::GetGLContext()->GetShaderSource(shader, bufsize, length, source);
@@ -387,6 +406,7 @@ void GLES2GetTexParameterfv(GLenum target, GLenum pname, GLfloat* params) {
   gles2::GetGLContext()->GetTexParameterfv(target, pname, params);
 }
 void GLES2GetTexParameteriv(GLenum target, GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetTexParameteriv" << "(" << target << ", " << pname << ", " << params << ")");  // NOLINT
   gles2::GetGLContext()->GetTexParameteriv(target, pname, params);
@@ -397,6 +417,7 @@ void GLES2GetUniformfv(GLuint program, GLint location, GLfloat* params) {
   gles2::GetGLContext()->GetUniformfv(program, location, params);
 }
 void GLES2GetUniformiv(GLuint program, GLint location, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetUniformiv" << "(" << program << ", " << location << ", " << params << ")");  // NOLINT
   gles2::GetGLContext()->GetUniformiv(program, location, params);
@@ -414,6 +435,7 @@ void GLES2GetVertexAttribfv(GLuint index, GLenum pname, GLfloat* params) {
   gles2::GetGLContext()->GetVertexAttribfv(index, pname, params);
 }
 void GLES2GetVertexAttribiv(GLuint index, GLenum pname, GLint* params) {
+  GL_CLIENT_VALIDATE_DESTINATION_INITALIZATION(GLint, params);
   GPU_CLIENT_LOG(
       "GetVertexAttribiv" << "(" << index << ", " << pname << ", " << params << ")");  // NOLINT
   gles2::GetGLContext()->GetVertexAttribiv(index, pname, params);
diff --git a/gpu/command_buffer/client/gles2_demo_cc.cc b/gpu/command_buffer/client/gles2_demo_cc.cc
index cb33f8c..a0ddaff 100644
--- a/gpu/command_buffer/client/gles2_demo_cc.cc
+++ b/gpu/command_buffer/client/gles2_demo_cc.cc
@@ -47,7 +47,7 @@ GLuint LoadShader(GLenum type, const char* shaderSrc) {
   // Compile the shader
   glCompileShader(shader);
   // Check the compile status
-  GLint value;
+  GLint value = 0;
   glGetShaderiv(shader, GL_COMPILE_STATUS, &value);
   if (value == 0) {
     char buffer[1024];
@@ -100,7 +100,7 @@ void InitShaders() {
   // Link the program
   glLinkProgram(programObject);
   // Check the link status
-  GLint linked;
+  GLint linked = 0;
   glGetProgramiv(programObject, GL_LINK_STATUS, &linked);
   if (linked == 0) {
     char buffer[1024];