source/disassemble.cpp - platform/external/shaderc/spirv-tools - Git at Google

 // Copyright (c) 2015-2016 The Khronos Group Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a
 // copy of this software and/or associated documentation files (the
 // "Materials"), to deal in the Materials without restriction, including
 // without limitation the rights to use, copy, modify, merge, publish,
 // distribute, sublicense, and/or sell copies of the Materials, and to
 // permit persons to whom the Materials are furnished to do so, subject to
 // the following conditions:
 //
 // The above copyright notice and this permission notice shall be included
 // in all copies or substantial portions of the Materials.
 //
 // MODIFICATIONS TO THIS FILE MAY MEAN IT NO LONGER ACCURATELY REFLECTS
 // KHRONOS STANDARDS. THE UNMODIFIED, NORMATIVE VERSIONS OF KHRONOS
 // SPECIFICATIONS AND HEADER INFORMATION ARE LOCATED AT
 //    https://www.khronos.org/registry/
 //
 // THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 // MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.

 // This file contains a disassembler:  It converts a SPIR-V binary
 // to text.

 #include <cassert>
 #include <cstring>
 #include <iomanip>
 #include <unordered_map>

 #include "assembly_grammar.h"
 #include "binary.h"
 #include "diagnostic.h"
 #include "ext_inst.h"
 #include "opcode.h"
 #include "print.h"
 #include "spirv-tools/libspirv.h"
 #include "spirv_constant.h"
 #include "spirv_endian.h"
 #include "util/hex_float.h"

 namespace {

 // A Disassembler instance converts a SPIR-V binary to its assembly
 // representation.
 class Disassembler {
  public:
   Disassembler(const libspirv::AssemblyGrammar& grammar, uint32_t options)
       : grammar_(grammar),
         print_(spvIsInBitfield(SPV_BINARY_TO_TEXT_OPTION_PRINT, options)),
         color_(print_ &&
                spvIsInBitfield(SPV_BINARY_TO_TEXT_OPTION_COLOR, options)),
         indent_(spvIsInBitfield(SPV_BINARY_TO_TEXT_OPTION_INDENT, options)
                     ? kStandardIndent
                     : 0),
         text_(),
         out_(print_ ? out_stream() : out_stream(text_)),
         stream_(out_.get()),
         show_byte_offset_(spvIsInBitfield(
             SPV_BINARY_TO_TEXT_OPTION_SHOW_BYTE_OFFSET, options)),
         byte_offset_(0) {}

   // Emits the assembly header for the module, and sets up internal state
   // so subsequent callbacks can handle the cases where the entire module
   // is either big-endian or little-endian.
   spv_result_t HandleHeader(spv_endianness_t endian, uint32_t version,
                             uint32_t generator, uint32_t id_bound,
                             uint32_t schema);
   // Emits the assembly text for the given instruction.
   spv_result_t HandleInstruction(const spv_parsed_instruction_t& inst);

   // If not printing, populates text_result with the accumulated text.
   // Returns SPV_SUCCESS on success.
   spv_result_t SaveTextResult(spv_text* text_result) const;

  private:
   enum { kStandardIndent = 15 };

   using out_stream = libspirv::out_stream;

   // Emits an operand for the given instruction, where the instruction
   // is at offset words from the start of the binary.
   void EmitOperand(const spv_parsed_instruction_t& inst,
                    const uint16_t operand_index);

   // Emits a mask expression for the given mask word of the specified type.
   void EmitMaskOperand(const spv_operand_type_t type, const uint32_t word);

   // Resets the output color, if color is turned on.
   void ResetColor() {
     if (color_) out_.get() << libspirv::clr::reset();
   }
   // Sets the output to grey, if color is turned on.
   void SetGrey() {
     if (color_) out_.get() << libspirv::clr::grey();
   }
   // Sets the output to blue, if color is turned on.
   void SetBlue() {
     if (color_) out_.get() << libspirv::clr::blue();
   }
   // Sets the output to yellow, if color is turned on.
   void SetYellow() {
     if (color_) out_.get() << libspirv::clr::yellow();
   }
   // Sets the output to red, if color is turned on.
   void SetRed() {
     if (color_) out_.get() << libspirv::clr::red();
   }
   // Sets the output to green, if color is turned on.
   void SetGreen() {
     if (color_) out_.get() << libspirv::clr::green();
   }

   const libspirv::AssemblyGrammar& grammar_;
   const bool print_;  // Should we also print to the standard output stream?
   const bool color_;  // Should we print in colour?
   const int indent_;  // How much to indent. 0 means don't indent
   spv_endianness_t endian_;  // The detected endianness of the binary.
   std::stringstream text_;   // Captures the text, if not printing.
   out_stream out_;  // The Output stream.  Either to text_ or standard output.
   std::ostream& stream_;  // The output std::stream.
   const bool show_byte_offset_;  // Should we print byte offset, in hex?
   size_t byte_offset_; // The number of bytes processed so far.
 };

 spv_result_t Disassembler::HandleHeader(spv_endianness_t endian,
                                         uint32_t version, uint32_t generator,
                                         uint32_t id_bound, uint32_t schema) {
   endian_ = endian;

   SetGrey();
   const char* generator_tool =
       spvGeneratorStr(SPV_GENERATOR_TOOL_PART(generator));
   stream_ << "; SPIR-V\n"
           << "; Version: " << SPV_SPIRV_VERSION_MAJOR_PART(version) << "."
           << SPV_SPIRV_VERSION_MINOR_PART(version) << "\n"
           << "; Generator: " << generator_tool;
   // For unknown tools, print the numeric tool value.
   if (0 == strcmp("Unknown", generator_tool)) {
     stream_ << "(" << SPV_GENERATOR_TOOL_PART(generator) << ")";
   }
   // Print the miscellaneous part of the generator word on the same
   // line as the tool name.
   stream_ << "; " << SPV_GENERATOR_MISC_PART(generator) << "\n"
           << "; Bound: " << id_bound << "\n"
           << "; Schema: " << schema << "\n";
   ResetColor();

   byte_offset_ = SPV_INDEX_INSTRUCTION * sizeof(uint32_t);

   return SPV_SUCCESS;
 }

 // Returns the number of digits in n.
 int NumDigits(uint32_t n) {
   if (n < 10) return 0;
   if (n < 100) return 1;
   if (n < 1000) return 2;
   if (n < 10000) return 3;
   if (n < 100000) return 4;
   if (n < 1000000) return 5;
   if (n < 10000000) return 6;
   if (n < 100000000) return 7;
   if (n < 1000000000) return 8;
   return 9;
 }

 spv_result_t Disassembler::HandleInstruction(
     const spv_parsed_instruction_t& inst) {
   if (inst.result_id) {
     SetBlue();
     // Indent if needed, but account for the 4 characters in "%" and " = "
     if (indent_) stream_ << std::setw(indent_ - 4 - NumDigits(inst.result_id));
     stream_ << "%" << inst.result_id;
     ResetColor();
     stream_ << " = ";
   } else {
     stream_ << std::string(indent_, ' ');
   }

   stream_ << "Op" << spvOpcodeString(inst.opcode);

   for (uint16_t i = 0; i < inst.num_operands; i++) {
     const spv_operand_type_t type = inst.operands[i].type;
     assert(type != SPV_OPERAND_TYPE_NONE);
     if (type == SPV_OPERAND_TYPE_RESULT_ID) continue;
     stream_ << " ";
     EmitOperand(inst, i);
   }

   if (show_byte_offset_) {
     SetGrey();
     auto saved_flags = stream_.flags();
     auto saved_fill = stream_.fill();
     stream_ << " ; 0x" << std::setw(8) << std::hex << std::setfill('0')
             << byte_offset_;
     stream_.flags(saved_flags);
     stream_.fill(saved_fill);
     ResetColor();
   }

   byte_offset_ += inst.num_words * sizeof(uint32_t);

   stream_ << "\n";
   return SPV_SUCCESS;
 }

 void Disassembler::EmitOperand(const spv_parsed_instruction_t& inst,
                                const uint16_t operand_index) {
   assert(operand_index < inst.num_operands);
   const spv_parsed_operand_t& operand = inst.operands[operand_index];
   const uint32_t word = inst.words[operand.offset];
   switch (operand.type) {
     case SPV_OPERAND_TYPE_RESULT_ID:
       assert(false && "<result-id> is not supposed to be handled here");
       SetBlue();
       stream_ << "%" << word;
       break;
     case SPV_OPERAND_TYPE_ID:
     case SPV_OPERAND_TYPE_TYPE_ID:
     case SPV_OPERAND_TYPE_SCOPE_ID:
     case SPV_OPERAND_TYPE_MEMORY_SEMANTICS_ID:
       SetYellow();
       stream_ << "%" << word;
       break;
     case SPV_OPERAND_TYPE_EXTENSION_INSTRUCTION_NUMBER: {
       spv_ext_inst_desc ext_inst;
       if (grammar_.lookupExtInst(inst.ext_inst_type, word, &ext_inst))
         assert(false && "should have caught this earlier");
       SetRed();
       stream_ << ext_inst->name;
     } break;
     case SPV_OPERAND_TYPE_SPEC_CONSTANT_OP_NUMBER: {
       spv_opcode_desc opcode_desc;
       if (grammar_.lookupOpcode(SpvOp(word), &opcode_desc))
         assert(false && "should have caught this earlier");
       SetRed();
       stream_ << opcode_desc->name;
     } break;
     case SPV_OPERAND_TYPE_LITERAL_INTEGER:
     case SPV_OPERAND_TYPE_TYPED_LITERAL_NUMBER: {
       SetRed();
       if (operand.num_words == 1) {
         switch (operand.number_kind) {
           case SPV_NUMBER_SIGNED_INT:
             stream_ << int32_t(word);
             break;
           case SPV_NUMBER_UNSIGNED_INT:
             stream_ << word;
             break;
           case SPV_NUMBER_FLOATING:
             if (operand.number_bit_width == 16) {
               stream_ << spvutils::FloatProxy<spvutils::Float16>(uint16_t(word & 0xFFFF));
             } else {
               // Assume 32-bit floats.
               stream_ << spvutils::FloatProxy<float>(word);
             }
             break;
           default:
             assert(false && "Unreachable");
         }
       } else if (operand.num_words == 2) {
         // Multi-word numbers are presented with lower order words first.
         uint64_t bits =
             uint64_t(word) | (uint64_t(inst.words[operand.offset + 1]) << 32);
         switch (operand.number_kind) {
           case SPV_NUMBER_SIGNED_INT:
             stream_ << int64_t(bits);
             break;
           case SPV_NUMBER_UNSIGNED_INT:
             stream_ << bits;
             break;
           case SPV_NUMBER_FLOATING:
             // Assume only 64-bit floats.
             stream_ << spvutils::FloatProxy<double>(bits);
             break;
           default:
             assert(false && "Unreachable");
         }
       } else {
         // TODO(dneto): Support more than 64-bits at a time.
         assert(false && "Unhandled");
       }
     } break;
     case SPV_OPERAND_TYPE_LITERAL_STRING: {
       stream_ << "\"";
       SetGreen();
       // Strings are always little-endian, and null-terminated.
       // Write out the characters, escaping as needed, and without copying
       // the entire string.
       auto c_str = reinterpret_cast<const char*>(inst.words + operand.offset);
       for (auto p = c_str; *p; ++p) {
         if (*p == '"' || *p == '\\') stream_ << '\\';
         stream_ << *p;
       }
       ResetColor();
       stream_ << '"';
     } break;
     case SPV_OPERAND_TYPE_CAPABILITY:
     case SPV_OPERAND_TYPE_SOURCE_LANGUAGE:
     case SPV_OPERAND_TYPE_EXECUTION_MODEL:
     case SPV_OPERAND_TYPE_ADDRESSING_MODEL:
     case SPV_OPERAND_TYPE_MEMORY_MODEL:
     case SPV_OPERAND_TYPE_EXECUTION_MODE:
     case SPV_OPERAND_TYPE_STORAGE_CLASS:
     case SPV_OPERAND_TYPE_DIMENSIONALITY:
     case SPV_OPERAND_TYPE_SAMPLER_ADDRESSING_MODE:
     case SPV_OPERAND_TYPE_SAMPLER_FILTER_MODE:
     case SPV_OPERAND_TYPE_SAMPLER_IMAGE_FORMAT:
     case SPV_OPERAND_TYPE_FP_ROUNDING_MODE:
     case SPV_OPERAND_TYPE_LINKAGE_TYPE:
     case SPV_OPERAND_TYPE_ACCESS_QUALIFIER:
     case SPV_OPERAND_TYPE_FUNCTION_PARAMETER_ATTRIBUTE:
     case SPV_OPERAND_TYPE_DECORATION:
     case SPV_OPERAND_TYPE_BUILT_IN:
     case SPV_OPERAND_TYPE_GROUP_OPERATION:
     case SPV_OPERAND_TYPE_KERNEL_ENQ_FLAGS:
     case SPV_OPERAND_TYPE_KERNEL_PROFILING_INFO: {
       spv_operand_desc entry;
       if (grammar_.lookupOperand(operand.type, word, &entry))
         assert(false && "should have caught this earlier");
       stream_ << entry->name;
     } break;
     case SPV_OPERAND_TYPE_FP_FAST_MATH_MODE:
     case SPV_OPERAND_TYPE_FUNCTION_CONTROL:
     case SPV_OPERAND_TYPE_LOOP_CONTROL:
     case SPV_OPERAND_TYPE_IMAGE:
     case SPV_OPERAND_TYPE_MEMORY_ACCESS:
     case SPV_OPERAND_TYPE_SELECTION_CONTROL:
       EmitMaskOperand(operand.type, word);
       break;
     default:
       assert(false && "unhandled or invalid case");
   }
   ResetColor();
 }

 void Disassembler::EmitMaskOperand(const spv_operand_type_t type,
                                    const uint32_t word) {
   // Scan the mask from least significant bit to most significant bit.  For each
   // set bit, emit the name of that bit. Separate multiple names with '|'.
   uint32_t remaining_word = word;
   uint32_t mask;
   int num_emitted = 0;
   for (mask = 1; remaining_word; mask <<= 1) {
     if (remaining_word & mask) {
       remaining_word ^= mask;
       spv_operand_desc entry;
       if (grammar_.lookupOperand(type, mask, &entry))
         assert(false && "should have caught this earlier");
       if (num_emitted) stream_ << "|";
       stream_ << entry->name;
       num_emitted++;
     }
   }
   if (!num_emitted) {
     // An operand value of 0 was provided, so represent it by the name
     // of the 0 value. In many cases, that's "None".
     spv_operand_desc entry;
     if (SPV_SUCCESS == grammar_.lookupOperand(type, 0, &entry))
       stream_ << entry->name;
   }
 }

 spv_result_t Disassembler::SaveTextResult(spv_text* text_result) const {
   if (!print_) {
     size_t length = text_.str().size();
     char* str = new char[length + 1];
     if (!str) return SPV_ERROR_OUT_OF_MEMORY;
     strncpy(str, text_.str().c_str(), length + 1);
     spv_text text = new spv_text_t();
     if (!text) {
       delete[] str;
       return SPV_ERROR_OUT_OF_MEMORY;
     }
     text->str = str;
     text->length = length;
     *text_result = text;
   }
   return SPV_SUCCESS;
 }

 spv_result_t DisassembleHeader(void* user_data, spv_endianness_t endian,
                                uint32_t /* magic */, uint32_t version,
                                uint32_t generator, uint32_t id_bound,
                                uint32_t schema) {
   assert(user_data);
   auto disassembler = static_cast<Disassembler*>(user_data);
   return disassembler->HandleHeader(endian, version, generator, id_bound,
                                     schema);
 }

 spv_result_t DisassembleInstruction(
     void* user_data, const spv_parsed_instruction_t* parsed_instruction) {
   assert(user_data);
   auto disassembler = static_cast<Disassembler*>(user_data);
   return disassembler->HandleInstruction(*parsed_instruction);
 }

 }  // anonymous namespace

 spv_result_t spvBinaryToText(const spv_const_context context,
                              const uint32_t* code, const size_t wordCount,
                              const uint32_t options, spv_text* pText,
                              spv_diagnostic* pDiagnostic) {
   // Invalid arguments return error codes, but don't necessarily generate
   // diagnostics.  These are programmer errors, not user errors.
   if (!pDiagnostic) return SPV_ERROR_INVALID_DIAGNOSTIC;
   const libspirv::AssemblyGrammar grammar(context);
   if (!grammar.isValid()) return SPV_ERROR_INVALID_TABLE;

   Disassembler disassembler(grammar, options);
   if (auto error = spvBinaryParse(context, &disassembler, code, wordCount,
                                   DisassembleHeader, DisassembleInstruction,
                                   pDiagnostic)) {
     return error;
   }

   return disassembler.SaveTextResult(pText);
 }
	// Copyright (c) 2015-2016 The Khronos Group Inc.
	//
	// Permission is hereby granted, free of charge, to any person obtaining a
	// copy of this software and/or associated documentation files (the
	// "Materials"), to deal in the Materials without restriction, including
	// without limitation the rights to use, copy, modify, merge, publish,
	// distribute, sublicense, and/or sell copies of the Materials, and to
	// permit persons to whom the Materials are furnished to do so, subject to
	// the following conditions:
	//
	// The above copyright notice and this permission notice shall be included
	// in all copies or substantial portions of the Materials.
	//
	// MODIFICATIONS TO THIS FILE MAY MEAN IT NO LONGER ACCURATELY REFLECTS
	// KHRONOS STANDARDS. THE UNMODIFIED, NORMATIVE VERSIONS OF KHRONOS
	// SPECIFICATIONS AND HEADER INFORMATION ARE LOCATED AT
	// https://www.khronos.org/registry/
	//
	// THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
	// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
	// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
	// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
	// MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.

	// This file contains a disassembler: It converts a SPIR-V binary
	// to text.

	#include <cassert>
	#include <cstring>
	#include <iomanip>
	#include <unordered_map>

	#include "assembly_grammar.h"
	#include "binary.h"
	#include "diagnostic.h"
	#include "ext_inst.h"
	#include "opcode.h"
	#include "print.h"
	#include "spirv-tools/libspirv.h"
	#include "spirv_constant.h"
	#include "spirv_endian.h"
	#include "util/hex_float.h"

	namespace {

	// A Disassembler instance converts a SPIR-V binary to its assembly
	// representation.
	class Disassembler {
	public:
	Disassembler(const libspirv::AssemblyGrammar& grammar, uint32_t options)
	: grammar_(grammar),
	print_(spvIsInBitfield(SPV_BINARY_TO_TEXT_OPTION_PRINT, options)),
	color_(print_ &&
	spvIsInBitfield(SPV_BINARY_TO_TEXT_OPTION_COLOR, options)),
	indent_(spvIsInBitfield(SPV_BINARY_TO_TEXT_OPTION_INDENT, options)
	? kStandardIndent
	: 0),
	text_(),
	out_(print_ ? out_stream() : out_stream(text_)),
	stream_(out_.get()),
	show_byte_offset_(spvIsInBitfield(
	SPV_BINARY_TO_TEXT_OPTION_SHOW_BYTE_OFFSET, options)),
	byte_offset_(0) {}

	// Emits the assembly header for the module, and sets up internal state
	// so subsequent callbacks can handle the cases where the entire module
	// is either big-endian or little-endian.
	spv_result_t HandleHeader(spv_endianness_t endian, uint32_t version,
	uint32_t generator, uint32_t id_bound,
	uint32_t schema);
	// Emits the assembly text for the given instruction.
	spv_result_t HandleInstruction(const spv_parsed_instruction_t& inst);

	// If not printing, populates text_result with the accumulated text.
	// Returns SPV_SUCCESS on success.
	spv_result_t SaveTextResult(spv_text* text_result) const;

	private:
	enum { kStandardIndent = 15 };

	using out_stream = libspirv::out_stream;

	// Emits an operand for the given instruction, where the instruction
	// is at offset words from the start of the binary.
	void EmitOperand(const spv_parsed_instruction_t& inst,
	const uint16_t operand_index);

	// Emits a mask expression for the given mask word of the specified type.
	void EmitMaskOperand(const spv_operand_type_t type, const uint32_t word);

	// Resets the output color, if color is turned on.
	void ResetColor() {
	if (color_) out_.get() << libspirv::clr::reset();
	}
	// Sets the output to grey, if color is turned on.
	void SetGrey() {
	if (color_) out_.get() << libspirv::clr::grey();
	}
	// Sets the output to blue, if color is turned on.
	void SetBlue() {
	if (color_) out_.get() << libspirv::clr::blue();
	}
	// Sets the output to yellow, if color is turned on.
	void SetYellow() {
	if (color_) out_.get() << libspirv::clr::yellow();
	}
	// Sets the output to red, if color is turned on.
	void SetRed() {
	if (color_) out_.get() << libspirv::clr::red();
	}
	// Sets the output to green, if color is turned on.
	void SetGreen() {
	if (color_) out_.get() << libspirv::clr::green();
	}

	const libspirv::AssemblyGrammar& grammar_;
	const bool print_; // Should we also print to the standard output stream?
	const bool color_; // Should we print in colour?
	const int indent_; // How much to indent. 0 means don't indent
	spv_endianness_t endian_; // The detected endianness of the binary.
	std::stringstream text_; // Captures the text, if not printing.
	out_stream out_; // The Output stream. Either to text_ or standard output.
	std::ostream& stream_; // The output std::stream.
	const bool show_byte_offset_; // Should we print byte offset, in hex?
	size_t byte_offset_; // The number of bytes processed so far.
	};

	spv_result_t Disassembler::HandleHeader(spv_endianness_t endian,
	uint32_t version, uint32_t generator,
	uint32_t id_bound, uint32_t schema) {
	endian_ = endian;

	SetGrey();
	const char* generator_tool =
	spvGeneratorStr(SPV_GENERATOR_TOOL_PART(generator));
	stream_ << "; SPIR-V\n"
	<< "; Version: " << SPV_SPIRV_VERSION_MAJOR_PART(version) << "."
	<< SPV_SPIRV_VERSION_MINOR_PART(version) << "\n"
	<< "; Generator: " << generator_tool;
	// For unknown tools, print the numeric tool value.
	if (0 == strcmp("Unknown", generator_tool)) {
	stream_ << "(" << SPV_GENERATOR_TOOL_PART(generator) << ")";
	}
	// Print the miscellaneous part of the generator word on the same
	// line as the tool name.
	stream_ << "; " << SPV_GENERATOR_MISC_PART(generator) << "\n"
	<< "; Bound: " << id_bound << "\n"
	<< "; Schema: " << schema << "\n";
	ResetColor();

	byte_offset_ = SPV_INDEX_INSTRUCTION * sizeof(uint32_t);

	return SPV_SUCCESS;
	}

	// Returns the number of digits in n.
	int NumDigits(uint32_t n) {
	if (n < 10) return 0;
	if (n < 100) return 1;
	if (n < 1000) return 2;
	if (n < 10000) return 3;
	if (n < 100000) return 4;
	if (n < 1000000) return 5;
	if (n < 10000000) return 6;
	if (n < 100000000) return 7;
	if (n < 1000000000) return 8;
	return 9;
	}

	spv_result_t Disassembler::HandleInstruction(
	const spv_parsed_instruction_t& inst) {
	if (inst.result_id) {
	SetBlue();
	// Indent if needed, but account for the 4 characters in "%" and " = "
	if (indent_) stream_ << std::setw(indent_ - 4 - NumDigits(inst.result_id));
	stream_ << "%" << inst.result_id;
	ResetColor();
	stream_ << " = ";
	} else {
	stream_ << std::string(indent_, ' ');
	}

	stream_ << "Op" << spvOpcodeString(inst.opcode);

	for (uint16_t i = 0; i < inst.num_operands; i++) {
	const spv_operand_type_t type = inst.operands[i].type;
	assert(type != SPV_OPERAND_TYPE_NONE);
	if (type == SPV_OPERAND_TYPE_RESULT_ID) continue;
	stream_ << " ";
	EmitOperand(inst, i);
	}

	if (show_byte_offset_) {
	SetGrey();
	auto saved_flags = stream_.flags();
	auto saved_fill = stream_.fill();
	stream_ << " ; 0x" << std::setw(8) << std::hex << std::setfill('0')
	<< byte_offset_;
	stream_.flags(saved_flags);
	stream_.fill(saved_fill);
	ResetColor();
	}

	byte_offset_ += inst.num_words * sizeof(uint32_t);

	stream_ << "\n";
	return SPV_SUCCESS;
	}

	void Disassembler::EmitOperand(const spv_parsed_instruction_t& inst,
	const uint16_t operand_index) {
	assert(operand_index < inst.num_operands);
	const spv_parsed_operand_t& operand = inst.operands[operand_index];
	const uint32_t word = inst.words[operand.offset];
	switch (operand.type) {
	case SPV_OPERAND_TYPE_RESULT_ID:
	assert(false && "<result-id> is not supposed to be handled here");
	SetBlue();
	stream_ << "%" << word;
	break;
	case SPV_OPERAND_TYPE_ID:
	case SPV_OPERAND_TYPE_TYPE_ID:
	case SPV_OPERAND_TYPE_SCOPE_ID:
	case SPV_OPERAND_TYPE_MEMORY_SEMANTICS_ID:
	SetYellow();
	stream_ << "%" << word;
	break;
	case SPV_OPERAND_TYPE_EXTENSION_INSTRUCTION_NUMBER: {
	spv_ext_inst_desc ext_inst;
	if (grammar_.lookupExtInst(inst.ext_inst_type, word, &ext_inst))
	assert(false && "should have caught this earlier");
	SetRed();
	stream_ << ext_inst->name;
	} break;
	case SPV_OPERAND_TYPE_SPEC_CONSTANT_OP_NUMBER: {
	spv_opcode_desc opcode_desc;
	if (grammar_.lookupOpcode(SpvOp(word), &opcode_desc))
	assert(false && "should have caught this earlier");
	SetRed();
	stream_ << opcode_desc->name;
	} break;
	case SPV_OPERAND_TYPE_LITERAL_INTEGER:
	case SPV_OPERAND_TYPE_TYPED_LITERAL_NUMBER: {
	SetRed();
	if (operand.num_words == 1) {
	switch (operand.number_kind) {
	case SPV_NUMBER_SIGNED_INT:
	stream_ << int32_t(word);
	break;
	case SPV_NUMBER_UNSIGNED_INT:
	stream_ << word;
	break;
	case SPV_NUMBER_FLOATING:
	if (operand.number_bit_width == 16) {
	stream_ << spvutils::FloatProxy<spvutils::Float16>(uint16_t(word & 0xFFFF));
	} else {
	// Assume 32-bit floats.
	stream_ << spvutils::FloatProxy<float>(word);
	}
	break;
	default:
	assert(false && "Unreachable");
	}
	} else if (operand.num_words == 2) {
	// Multi-word numbers are presented with lower order words first.
	uint64_t bits =
	uint64_t(word) \| (uint64_t(inst.words[operand.offset + 1]) << 32);
	switch (operand.number_kind) {
	case SPV_NUMBER_SIGNED_INT:
	stream_ << int64_t(bits);
	break;
	case SPV_NUMBER_UNSIGNED_INT:
	stream_ << bits;
	break;
	case SPV_NUMBER_FLOATING:
	// Assume only 64-bit floats.
	stream_ << spvutils::FloatProxy<double>(bits);
	break;
	default:
	assert(false && "Unreachable");
	}
	} else {
	// TODO(dneto): Support more than 64-bits at a time.
	assert(false && "Unhandled");
	}
	} break;
	case SPV_OPERAND_TYPE_LITERAL_STRING: {
	stream_ << "\"";
	SetGreen();
	// Strings are always little-endian, and null-terminated.
	// Write out the characters, escaping as needed, and without copying
	// the entire string.
	auto c_str = reinterpret_cast<const char*>(inst.words + operand.offset);
	for (auto p = c_str; *p; ++p) {
	if (p == '"' \|\| p == '\\') stream_ << '\\';
	stream_ << *p;
	}
	ResetColor();
	stream_ << '"';
	} break;
	case SPV_OPERAND_TYPE_CAPABILITY:
	case SPV_OPERAND_TYPE_SOURCE_LANGUAGE:
	case SPV_OPERAND_TYPE_EXECUTION_MODEL:
	case SPV_OPERAND_TYPE_ADDRESSING_MODEL:
	case SPV_OPERAND_TYPE_MEMORY_MODEL:
	case SPV_OPERAND_TYPE_EXECUTION_MODE:
	case SPV_OPERAND_TYPE_STORAGE_CLASS:
	case SPV_OPERAND_TYPE_DIMENSIONALITY:
	case SPV_OPERAND_TYPE_SAMPLER_ADDRESSING_MODE:
	case SPV_OPERAND_TYPE_SAMPLER_FILTER_MODE:
	case SPV_OPERAND_TYPE_SAMPLER_IMAGE_FORMAT:
	case SPV_OPERAND_TYPE_FP_ROUNDING_MODE:
	case SPV_OPERAND_TYPE_LINKAGE_TYPE:
	case SPV_OPERAND_TYPE_ACCESS_QUALIFIER:
	case SPV_OPERAND_TYPE_FUNCTION_PARAMETER_ATTRIBUTE:
	case SPV_OPERAND_TYPE_DECORATION:
	case SPV_OPERAND_TYPE_BUILT_IN:
	case SPV_OPERAND_TYPE_GROUP_OPERATION:
	case SPV_OPERAND_TYPE_KERNEL_ENQ_FLAGS:
	case SPV_OPERAND_TYPE_KERNEL_PROFILING_INFO: {
	spv_operand_desc entry;
	if (grammar_.lookupOperand(operand.type, word, &entry))
	assert(false && "should have caught this earlier");
	stream_ << entry->name;
	} break;
	case SPV_OPERAND_TYPE_FP_FAST_MATH_MODE:
	case SPV_OPERAND_TYPE_FUNCTION_CONTROL:
	case SPV_OPERAND_TYPE_LOOP_CONTROL:
	case SPV_OPERAND_TYPE_IMAGE:
	case SPV_OPERAND_TYPE_MEMORY_ACCESS:
	case SPV_OPERAND_TYPE_SELECTION_CONTROL:
	EmitMaskOperand(operand.type, word);
	break;
	default:
	assert(false && "unhandled or invalid case");
	}
	ResetColor();
	}

	void Disassembler::EmitMaskOperand(const spv_operand_type_t type,
	const uint32_t word) {
	// Scan the mask from least significant bit to most significant bit. For each
	// set bit, emit the name of that bit. Separate multiple names with '\|'.
	uint32_t remaining_word = word;
	uint32_t mask;
	int num_emitted = 0;
	for (mask = 1; remaining_word; mask <<= 1) {
	if (remaining_word & mask) {
	remaining_word ^= mask;
	spv_operand_desc entry;
	if (grammar_.lookupOperand(type, mask, &entry))
	assert(false && "should have caught this earlier");
	if (num_emitted) stream_ << "\|";
	stream_ << entry->name;
	num_emitted++;
	}
	}
	if (!num_emitted) {
	// An operand value of 0 was provided, so represent it by the name
	// of the 0 value. In many cases, that's "None".
	spv_operand_desc entry;
	if (SPV_SUCCESS == grammar_.lookupOperand(type, 0, &entry))
	stream_ << entry->name;
	}
	}

	spv_result_t Disassembler::SaveTextResult(spv_text* text_result) const {
	if (!print_) {
	size_t length = text_.str().size();
	char* str = new char[length + 1];
	if (!str) return SPV_ERROR_OUT_OF_MEMORY;
	strncpy(str, text_.str().c_str(), length + 1);
	spv_text text = new spv_text_t();
	if (!text) {
	delete[] str;
	return SPV_ERROR_OUT_OF_MEMORY;
	}
	text->str = str;
	text->length = length;
	*text_result = text;
	}
	return SPV_SUCCESS;
	}

	spv_result_t DisassembleHeader(void* user_data, spv_endianness_t endian,
	uint32_t /* magic */, uint32_t version,
	uint32_t generator, uint32_t id_bound,
	uint32_t schema) {
	assert(user_data);
	auto disassembler = static_cast<Disassembler*>(user_data);
	return disassembler->HandleHeader(endian, version, generator, id_bound,
	schema);
	}

	spv_result_t DisassembleInstruction(
	void* user_data, const spv_parsed_instruction_t* parsed_instruction) {
	assert(user_data);
	auto disassembler = static_cast<Disassembler*>(user_data);
	return disassembler->HandleInstruction(*parsed_instruction);
	}

	} // anonymous namespace

	spv_result_t spvBinaryToText(const spv_const_context context,
	const uint32_t* code, const size_t wordCount,
	const uint32_t options, spv_text* pText,
	spv_diagnostic* pDiagnostic) {
	// Invalid arguments return error codes, but don't necessarily generate
	// diagnostics. These are programmer errors, not user errors.
	if (!pDiagnostic) return SPV_ERROR_INVALID_DIAGNOSTIC;
	const libspirv::AssemblyGrammar grammar(context);
	if (!grammar.isValid()) return SPV_ERROR_INVALID_TABLE;

	Disassembler disassembler(grammar, options);
	if (auto error = spvBinaryParse(context, &disassembler, code, wordCount,
	DisassembleHeader, DisassembleInstruction,
	pDiagnostic)) {
	return error;
	}

	return disassembler.SaveTextResult(pText);
	}