Value-initialize all vk::GraphicsState members

The vk::GraphicsState constructor does not initialize all members in all code paths. We were relying on the zero-initializing done by vk::allocate() which is used to allocate vk::GraphicsPipeline which in turn contains a GraphicsState member. We want to change vk::allocate() to no longer zero-initialize all memory, to catch more MemorySanitizer errors made by applications. Thus we must also not rely on such automatic initialization ourselves. Note that this change might also hide MemorySantizer violations committed by the application side. For example some state is only copied from VkGraphicsPipelineCreateInfo into vk::GraphicsState on construction when flags indicate they're not dynamic state. If the application forgets to makerecord commands that set the dynamic state, their value is undefined: Vulkan 1.2.178 section 6. Command Buffers: "When a command buffer begins recording, all state in that command buffer is undefined." Vulkan 1.2.178 section 10.11. Dynamic State: "If the state is specified as dynamic in the new pipeline object, then that command buffer state is not disturbed. Before any draw or dispatch call with this pipeline there must have been at least one call to each of the corresponding dynamic state setting commands since the command buffer recording was begun, or the last bound pipeline object with that state specified as static, whichever was the latter." Thus once sw::allocate() no longer also zeroes this data, we should revert the value-initialization where possible and ensure we don't touch the uninitialized data ourselves, unless as a consequence of an application bug. Bug: b/140991626 Change-Id: I060e8d8a79e93b0676669eed361fab4f86ab1b56 Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/53089 Presubmit-Ready: Nicolas Capens <nicolascapens@google.com> Kokoro-Result: kokoro <noreply+kokoro@google.com> Tested-by: Nicolas Capens <nicolascapens@google.com> Reviewed-by: Alexis Hétu <sugoi@google.com>

Value-initialize all vk::GraphicsState members
940f2acc · Nicolas Capens · Nicolas Capens · 491ade49 · 940f2acc
Commit 940f2acc authored Feb 20, 2021 by Nicolas Capens Committed by Nicolas Capens Jun 03, 2021
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Showing with 34 additions and 34 deletions

Context.hpp src/Device/Context.hpp +34 -34

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--- a/src/Device/Context.hpp
+++ b/src/Device/Context.hpp
@@ -204,55 +204,55 @@ private:
 	bool alphaBlendActive(int index, const Attachments &attachments, bool fragmentContainsKill) const;
 	bool colorWriteActive(const Attachments &attachments) const;

-	const PipelineLayout *pipelineLayout;
-	const bool robustBufferAccess = true;
+	const PipelineLayout *pipelineLayout = nullptr;
+	const bool robustBufferAccess = false;
 	uint32_t dynamicStateFlags = 0;
-	VkPrimitiveTopology topology;
+	VkPrimitiveTopology topology = VK_PRIMITIVE_TOPOLOGY_POINT_LIST;

-	VkProvokingVertexModeEXT provokingVertexMode;
+	VkProvokingVertexModeEXT provokingVertexMode = VK_PROVOKING_VERTEX_MODE_FIRST_VERTEX_EXT;

-	bool stencilEnable;
-	VkStencilOpState frontStencil;
-	VkStencilOpState backStencil;
+	bool stencilEnable = false;
+	VkStencilOpState frontStencil = {};
+	VkStencilOpState backStencil = {};

 	// Pixel processor states
-	VkCullModeFlags cullMode;
-	VkFrontFace frontFace;
-	VkPolygonMode polygonMode;
-	VkLineRasterizationModeEXT lineRasterizationMode;
-
-	float constantDepthBias;
-	float slopeDepthBias;
-	float depthBiasClamp;
-	float minDepthBounds;
-	float maxDepthBounds;
-	bool depthRangeUnrestricted;
+	VkCullModeFlags cullMode = 0;
+	VkFrontFace frontFace = VK_FRONT_FACE_COUNTER_CLOCKWISE;
+	VkPolygonMode polygonMode = VK_POLYGON_MODE_FILL;
+	VkLineRasterizationModeEXT lineRasterizationMode = VK_LINE_RASTERIZATION_MODE_DEFAULT_EXT;
+
+	float constantDepthBias = 0.0f;
+	float slopeDepthBias = 0.0f;
+	float depthBiasClamp = 0.0f;
+	float minDepthBounds = 0.0f;
+	float maxDepthBounds = 0.0f;
+	bool depthRangeUnrestricted = false;

 	// Pixel processor states
-	bool rasterizerDiscard;
-	bool depthBoundsTestEnable;
-	bool depthBufferEnable;
-	VkCompareOp depthCompareMode;
-	bool depthWriteEnable;
-	bool depthClampEnable;
-	bool depthClipEnable;
+	bool rasterizerDiscard = false;
+	bool depthBoundsTestEnable = false;
+	bool depthBufferEnable = false;
+	VkCompareOp depthCompareMode = VK_COMPARE_OP_NEVER;
+	bool depthWriteEnable = false;
+	bool depthClampEnable = false;
+	bool depthClipEnable = false;

-	float lineWidth;
+	float lineWidth = 0.0f;

-	int colorWriteMask[sw::RENDERTARGETS];  // RGBA
-	unsigned int multiSampleMask;
-	int sampleCount;
-	bool alphaToCoverage;
+	int colorWriteMask[sw::RENDERTARGETS] = {};  // RGBA
+	unsigned int multiSampleMask = 0;
+	int sampleCount = 0;
+	bool alphaToCoverage = false;

 	bool sampleShadingEnable = false;
 	float minSampleShading = 0.0f;

 	bool primitiveRestartEnable = false;
-	VkRect2D scissor;
-	VkViewport viewport;
-	sw::float4 blendConstants;
+	VkRect2D scissor = {};
+	VkViewport viewport = {};
+	sw::float4 blendConstants = {};

-	BlendState blendState[sw::RENDERTARGETS];
+	BlendState blendState[sw::RENDERTARGETS] = {};
 };

 }  // namespace vk