text: // Copyright (c) 2016 Google Inc.
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #include <algorithm>
  #include <cassert>
  #include <cstring>
  #include <fstream>
  #include <iostream>
  #include <memory>
  #include <sstream>
  #include <string>
  #include <vector>
  
  #include "source/opt/log.h"
  #include "source/spirv_target_env.h"
  #include "source/util/string_utils.h"
  #include "spirv-tools/libspirv.hpp"
  #include "spirv-tools/optimizer.hpp"
  #include "tools/io.h"
  #include "tools/util/cli_consumer.h"
  
  namespace {
  
  // Status and actions to perform after parsing command-line arguments.
  enum OptActions { OPT_CONTINUE, OPT_STOP };
  
  struct OptStatus {
    OptActions action;
    int code;
  };
  
  // Message consumer for this tool.  Used to emit diagnostics during
  // initialization and setup. Note that |source| and |position| are irrelevant
  // here because we are still not processing a SPIR-V input file.
  void opt_diagnostic(spv_message_level_t level, const char* /*source*/,
                      const spv_position_t& /*positon*/, const char* message) {
    if (level == SPV_MSG_ERROR) {
      fprintf(stderr, "error: ");
    }
    fprintf(stderr, "%s\n", message);
  }
  
  std::string GetListOfPassesAsString(const spvtools::Optimizer& optimizer) {
    std::stringstream ss;
    for (const auto& name : optimizer.GetPassNames()) {
      ss << "\n\t\t" << name;
    }
    return ss.str();
  }
  
  const auto kDefaultEnvironment = SPV_ENV_UNIVERSAL_1_4;
  
  std::string GetLegalizationPasses() {
    spvtools::Optimizer optimizer(kDefaultEnvironment);
    optimizer.RegisterLegalizationPasses();
    return GetListOfPassesAsString(optimizer);
  }
  
  std::string GetOptimizationPasses() {
    spvtools::Optimizer optimizer(kDefaultEnvironment);
    optimizer.RegisterPerformancePasses();
    return GetListOfPassesAsString(optimizer);
  }
  
  std::string GetSizePasses() {
    spvtools::Optimizer optimizer(kDefaultEnvironment);
    optimizer.RegisterSizePasses();
    return GetListOfPassesAsString(optimizer);
  }
  
  std::string GetVulkanToWebGPUPasses() {
    spvtools::Optimizer optimizer(SPV_ENV_WEBGPU_0);
    optimizer.RegisterVulkanToWebGPUPasses();
    return GetListOfPassesAsString(optimizer);
  }
  
  std::string GetWebGPUToVulkanPasses() {
    spvtools::Optimizer optimizer(SPV_ENV_VULKAN_1_1);
    optimizer.RegisterWebGPUToVulkanPasses();
    return GetListOfPassesAsString(optimizer);
  }
  
  void PrintUsage(const char* program) {
    std::string target_env_list = spvTargetEnvList(16, 80);
    // NOTE: Please maintain flags in lexicographical order.
    printf(
        R"(%s - Optimize a SPIR-V binary file.
  
  USAGE: %s [options] [<input>] -o <output>
  
  The SPIR-V binary is read from <input>. If no file is specified,
  or if <input> is "-", then the binary is read from standard input.
  if <output> is "-", then the optimized output is written to
  standard output.
  
  NOTE: The optimizer is a work in progress.
  
  Options (in lexicographical order):)",
        program, program);
    printf(R"(
    --ccp
                 Apply the conditional constant propagation transform.  This will
                 propagate constant values throughout the program, and simplify
                 expressions and conditional jumps with known predicate
                 values.  Performed on entry point call tree functions and
                 exported functions.)");
    printf(R"(
    --cfg-cleanup
                 Cleanup the control flow graph. This will remove any unnecessary
                 code from the CFG like unreachable code. Performed on entry
                 point call tree functions and exported functions.)");
    printf(R"(
    --combine-access-chains
                 Combines chained access chains to produce a single instruction
                 where possible.)");
    printf(R"(
    --compact-ids
                 Remap result ids to a compact range starting from %%1 and without
                 any gaps.)");
    printf(R"(
    --convert-local-access-chains
                 Convert constant index access chain loads/stores into
                 equivalent load/stores with inserts and extracts. Performed
                 on function scope variables referenced only with load, store,
                 and constant index access chains in entry point call tree
                 functions.)");
    printf(R"(
    --copy-propagate-arrays
                 Does propagation of memory references when an array is a copy of
                 another.  It will only propagate an array if the source is never
                 written to, and the only store to the target is the copy.)");
    printf(R"(
    --decompose-initialized-variables
                 Decomposes initialized variable declarations into a declaration
                 followed by a store of the initial value. This is done to work
                 around known issues with some Vulkan drivers for initialize
                 variables.)");
    printf(R"(
    --eliminate-common-uniform
                 Perform load/load elimination for duplicate uniform values.
                 Converts any constant index access chain uniform loads into
                 its equivalent load and extract. Some loads will be moved
                 to facilitate sharing. Performed only on entry point
                 call tree functions.)");
    printf(R"(
    --eliminate-dead-branches
                 Convert conditional branches with constant condition to the
                 indicated unconditional brranch. Delete all resulting dead
                 code. Performed only on entry point call tree functions.)");
    printf(R"(
    --eliminate-dead-code-aggressive
                 Delete instructions which do not contribute to a function's
                 output. Performed only on entry point call tree functions.)");
    printf(R"(
    --eliminate-dead-const
                 Eliminate dead constants.)");
    printf(R"(
    --eliminate-dead-functions
                 Deletes functions that cannot be reached from entry points or
                 exported functions.)");
    printf(R"(
    --eliminate-dead-inserts
                 Deletes unreferenced inserts into composites, most notably
                 unused stores to vector components, that are not removed by
                 aggressive dead code elimination.)");
    printf(R"(
    --eliminate-dead-variables
                 Deletes module scope variables that are not referenced.)");
    printf(R"(
    --eliminate-insert-extract
                 DEPRECATED.  This pass has been replaced by the simplification
                 pass, and that pass will be run instead.
                 See --simplify-instructions.)");
    printf(R"(
    --eliminate-local-multi-store
                 Replace stores and loads of function scope variables that are
                 stored multiple times. Performed on variables referenceed only
                 with loads and stores. Performed only on entry point call tree
                 functions.)");
    printf(R"(
    --eliminate-local-single-block
                 Perform single-block store/load and load/load elimination.
                 Performed only on function scope variables in entry point
                 call tree functions.)");
    printf(R"(
    --eliminate-local-single-store
                 Replace stores and loads of function scope variables that are
                 only stored once. Performed on variables referenceed only with
                 loads and stores. Performed only on entry point call tree
                 functions.)");
    printf(R"(
    --flatten-decorations
                 Replace decoration groups with repeated OpDecorate and
                 OpMemberDecorate instructions.)");
    printf(R"(
    --fold-spec-const-op-composite
                 Fold the spec constants defined by OpSpecConstantOp or
                 OpSpecConstantComposite instructions to front-end constants
                 when possible.)");
    printf(R"(
    --freeze-spec-const
                 Freeze the values of specialization constants to their default
                 values.)");
    printf(R"(
    --generate-webgpu-initializers
                 Adds initial values to OpVariable instructions that are missing
                 them, due to their storage type requiring them for WebGPU.)");
    printf(R"(
    --if-conversion
                 Convert if-then-else like assignments into OpSelect.)");
    printf(R"(
    --inline-entry-points-exhaustive
                 Exhaustively inline all function calls in entry point call tree
                 functions. Currently does not inline calls to functions with
                 early return in a loop.)");
    printf(R"(
    --legalize-hlsl
                 Runs a series of optimizations that attempts to take SPIR-V
                 generated by an HLSL front-end and generates legal Vulkan SPIR-V.
                 The optimizations are:
                 %s
  
                 Note this does not guarantee legal code. This option passes the
                 option --relax-logical-pointer to the validator.)",
           GetLegalizationPasses().c_str());
    printf(R"(
    --legalize-vector-shuffle
                 Converts any usages of 0xFFFFFFFF for the literals in
                 OpVectorShuffle to a literal 0. This is done since 0xFFFFFFFF is
                 forbidden in WebGPU.)");
    printf(R"(
    --local-redundancy-elimination
                 Looks for instructions in the same basic block that compute the
                 same value, and deletes the redundant ones.)");
    printf(R"(
    --loop-fission
                 Splits any top level loops in which the register pressure has
                 exceeded a given threshold. The threshold must follow the use of
                 this flag and must be a positive integer value.)");
    printf(R"(
    --loop-fusion
                 Identifies adjacent loops with the same lower and upper bound.
                 If this is legal, then merge the loops into a single loop.
                 Includes heuristics to ensure it does not increase number of
                 registers too much, while reducing the number of loads from
                 memory. Takes an additional positive integer argument to set
                 the maximum number of registers.)");
    printf(R"(
    --loop-invariant-code-motion
                 Identifies code in loops that has the same value for every
                 iteration of the loop, and move it to the loop pre-header.)");
    printf(R"(
    --loop-unroll
                 Fully unrolls loops marked with the Unroll flag)");
    printf(R"(
    --loop-unroll-partial
                 Partially unrolls loops marked with the Unroll flag. Takes an
                 additional non-0 integer argument to set the unroll factor, or
                 how many times a loop body should be duplicated)");
    printf(R"(
    --loop-peeling
                 Execute few first (respectively last) iterations before
                 (respectively after) the loop if it can elide some branches.)");
    printf(R"(
    --loop-peeling-threshold
                 Takes a non-0 integer argument to set the loop peeling code size
                 growth threshold. The threshold prevents the loop peeling
                 from happening if the code size increase created by
                 the optimization is above the threshold.)");
    printf(R"(
    --max-id-bound=<n>
                 Sets the maximum value for the id bound for the moudle.  The
                 default is the minimum value for this limit, 0x3FFFFF.  See
                 section 2.17 of the Spir-V specification.)");
    printf(R"(
    --merge-blocks
                 Join two blocks into a single block if the second has the
                 first as its only predecessor. Performed only on entry point
                 call tree functions.)");
    printf(R"(
    --merge-return
                 Changes functions that have multiple return statements so they
                 have a single return statement.
  
                 For structured control flow it is assumed that the only
                 unreachable blocks in the function are trivial merge and continue
                 blocks.
  
                 A trivial merge block contains the label and an OpUnreachable
                 instructions, nothing else.  A trivial continue block contain a
                 label and an OpBranch to the header, nothing else.
  
                 These conditions are guaranteed to be met after running
                 dead-branch elimination.)");
    printf(R"(
    --loop-unswitch
                 Hoists loop-invariant conditionals out of loops by duplicating
                 the loop on each branch of the conditional and adjusting each
                 copy of the loop.)");
    printf(R"(
    -O
                 Optimize for performance. Apply a sequence of transformations
                 in an attempt to improve the performance of the generated
                 code. For this version of the optimizer, this flag is equivalent
                 to specifying the following optimization code names:
                 %s)",
           GetOptimizationPasses().c_str());
    printf(R"(
    -Os
                 Optimize for size. Apply a sequence of transformations in an
                 attempt to minimize the size of the generated code. For this
                 version of the optimizer, this flag is equivalent to specifying
                 the following optimization code names:
                 %s
  
                 NOTE: The specific transformations done by -O and -Os change
                       from release to release.)",
           GetSizePasses().c_str());
    printf(R"(
    -Oconfig=<file>
                 Apply the sequence of transformations indicated in <file>.
                 This file contains a sequence of strings separated by whitespace
                 (tabs, newlines or blanks). Each string is one of the flags
                 accepted by spirv-opt. Optimizations will be applied in the
                 sequence they appear in the file. This is equivalent to
                 specifying all the flags on the command line. For example,
                 given the file opts.cfg with the content:
  
                  --inline-entry-points-exhaustive
                  --eliminate-dead-code-aggressive
  
                 The following two invocations to spirv-opt are equivalent:
  
                 $ spirv-opt -Oconfig=opts.cfg program.spv
  
                 $ spirv-opt --inline-entry-points-exhaustive \
                      --eliminate-dead-code-aggressive program.spv
  
                 Lines starting with the character '#' in the configuration
                 file indicate a comment and will be ignored.
  
                 The -O, -Os, and -Oconfig flags act as macros. Using one of them
                 is equivalent to explicitly inserting the underlying flags at
                 that position in the command line. For example, the invocation
                 'spirv-opt --merge-blocks -O ...' applies the transformation
                 --merge-blocks followed by all the transformations implied by
                 -O.)");
    printf(R"(
    --preserve-bindings
                 Ensure that the optimizer preserves all bindings declared within
                 the module, even when those bindings are unused.)");
    printf(R"(
    --preserve-spec-constants
                 Ensure that the optimizer preserves all specialization constants declared
                 within the module, even when those constants are unused.)");
    printf(R"(
    --print-all
                 Print SPIR-V assembly to standard error output before each pass
                 and after the last pass.)");
    printf(R"(
    --private-to-local
                 Change the scope of private variables that are used in a single
                 function to that function.)");
    printf(R"(
    --reduce-load-size
                 Replaces loads of composite objects where not every component is
                 used by loads of just the elements that are used.)");
    printf(R"(
    --redundancy-elimination
                 Looks for instructions in the same function that compute the
                 same value, and deletes the redundant ones.)");
    printf(R"(
    --relax-struct-store
                 Allow store from one struct type to a different type with
                 compatible layout and members. This option is forwarded to the
                 validator.)");
    printf(R"(
    --remove-duplicates
                 Removes duplicate types, decorations, capabilities and extension
                 instructions.)");
    printf(R"(
    --replace-invalid-opcode
                 Replaces instructions whose opcode is valid for shader modules,
                 but not for the current shader stage.  To have an effect, all
                 entry points must have the same execution model.)");
    printf(R"(
    --ssa-rewrite
                 Replace loads and stores to function local variables with
                 operations on SSA IDs.)");
    printf(R"(
    --scalar-replacement[=<n>]
                 Replace aggregate function scope variables that are only accessed
                 via their elements with new function variables representing each
                 element.  <n> is a limit on the size of the aggragates that will
                 be replaced.  0 means there is no limit.  The default value is
                 100.)");
    printf(R"(
    --set-spec-const-default-value "<spec id>:<default value> ..."
                 Set the default values of the specialization constants with
                 <spec id>:<default value> pairs specified in a double-quoted
                 string. <spec id>:<default value> pairs must be separated by
                 blank spaces, and in each pair, spec id and default value must
                 be separated with colon ':' without any blank spaces in between.
                 e.g.: --set-spec-const-default-value "1:100 2:400")");
    printf(R"(
    --simplify-instructions
                 Will simplify all instructions in the function as much as
                 possible.)");
    printf(R"(
    --split-invalid-unreachable
                 Attempts to legalize for WebGPU cases where an unreachable
                 merge-block is also a continue-target by splitting it into two
                 seperate blocks. There exist legal, for Vulkan, instances of this
                 pattern that cannot be converted into legal WebGPU, so this
                 conversion may not succeed.)");
    printf(R"(
    --skip-validation
                 Will not validate the SPIR-V before optimizing.  If the SPIR-V
                 is invalid, the optimizer may fail or generate incorrect code.
                 This options should be used rarely, and with caution.)");
    printf(R"(
    --strength-reduction
                 Replaces instructions with equivalent and less expensive ones.)");
    printf(R"(
    --strip-atomic-counter-memory
                 Removes AtomicCountMemory bit from memory semantics values.)");
    printf(R"(
    --strip-debug
                 Remove all debug instructions.)");
    printf(R"(
    --strip-reflect
                 Remove all reflection information.  For now, this covers
                 reflection information defined by SPV_GOOGLE_hlsl_functionality1.)");
    printf(R"(
    --target-env=<env>
                 Set the target environment. Without this flag the target
                 enviroment defaults to spv1.3. <env> must be one of
                 {%s})",
           target_env_list.c_str());
    printf(R"(
    --time-report
                 Print the resource utilization of each pass (e.g., CPU time,
                 RSS) to standard error output. Currently it supports only Unix
                 systems. This option is the same as -ftime-report in GCC. It
                 prints CPU/WALL/USR/SYS time (and RSS if possible), but note that
                 USR/SYS time are returned by getrusage() and can have a small
                 error.)");
    printf(R"(
    --upgrade-memory-model
                 Upgrades the Logical GLSL450 memory model to Logical VulkanKHR.
                 Transforms memory, image, atomic and barrier operations to conform
                 to that model's requirements.)");
    printf(R"(
    --vector-dce
                 This pass looks for components of vectors that are unused, and
                 removes them from the vector.  Note this would still leave around
                 lots of dead code that a pass of ADCE will be able to remove.)");
    printf(R"(
    --vulkan-to-webgpu
                 Turns on the prescribed passes for converting from Vulkan to
                 WebGPU and sets the target environment to webgpu0. Other passes
                 may be turned on via additional flags, but such combinations are
                 not tested.
                 Using --target-env with this flag is not allowed.
  
                 This flag is the equivalent of passing in --target-env=webgpu0
                 and specifying the following optimization code names:
                 %s
  
                 NOTE: This flag is a WIP and its behaviour is subject to change.)",
           GetVulkanToWebGPUPasses().c_str());
    printf(R"(
    --webgpu-to-vulkan
                 Turns on the prescribed passes for converting from WebGPU to
                 Vulkan and sets the target environment to vulkan1.1. Other passes
                 may be turned on via additional flags, but such combinations are
                 not tested.
                 Using --target-env with this flag is not allowed.
  
                 This flag is the equivalent of passing in --target-env=vulkan1.1
                 and specifying the following optimization code names:
                 %s
  
                 NOTE: This flag is a WIP and its behaviour is subject to change.)",
           GetWebGPUToVulkanPasses().c_str());
    printf(R"(
    --workaround-1209
                 Rewrites instructions for which there are known driver bugs to
                 avoid triggering those bugs.
                 Current workarounds: Avoid OpUnreachable in loops.)");
    printf(R"(
    --unify-const
                 Remove the duplicated constants.)");
    printf(R"(
    --validate-after-all
                 Validate the module after each pass is performed.)");
    printf(R"(
    -h, --help
                 Print this help.)");
    printf(R"(
    --version
                 Display optimizer version information.
  )");
  }
  
  // Reads command-line flags  the file specified in |oconfig_flag|. This string
  // is assumed to have the form "-Oconfig=FILENAME". This function parses the
  // string and extracts the file name after the '=' sign.
  //
  // Flags found in |FILENAME| are pushed at the end of the vector |file_flags|.
  //
  // This function returns true on success, false on failure.
  bool ReadFlagsFromFile(const char* oconfig_flag,
                         std::vector<std::string>* file_flags) {
    const char* fname = strchr(oconfig_flag, '=');
    if (fname == nullptr || fname[0] != '=') {
      spvtools::Errorf(opt_diagnostic, nullptr, {}, "Invalid -Oconfig flag %s",
                       oconfig_flag);
      return false;
    }
    fname++;
  
    std::ifstream input_file;
    input_file.open(fname);
    if (input_file.fail()) {
      spvtools::Errorf(opt_diagnostic, nullptr, {}, "Could not open file '%s'",
                       fname);
      return false;
    }
  
    std::string line;
    while (std::getline(input_file, line)) {
      // Ignore empty lines and lines starting with the comment marker '#'.
      if (line.length() == 0 || line[0] == '#') {
        continue;
      }
  
      // Tokenize the line.  Add all found tokens to the list of found flags. This
      // mimics the way the shell will parse whitespace on the command line. NOTE:
      // This does not support quoting and it is not intended to.
      std::istringstream iss(line);
      while (!iss.eof()) {
        std::string flag;
        iss >> flag;
        file_flags->push_back(flag);
      }
    }
  
    return true;
  }
  
  OptStatus ParseFlags(int argc, const char** argv,
                       spvtools::Optimizer* optimizer, const char** in_file,
                       const char** out_file,
                       spvtools::ValidatorOptions* validator_options,
                       spvtools::OptimizerOptions* optimizer_options);
  
  // Parses and handles the -Oconfig flag. |prog_name| contains the name of
  // the spirv-opt binary (used to build a new argv vector for the recursive
  // invocation to ParseFlags). |opt_flag| contains the -Oconfig=FILENAME flag.
  // |optimizer|, |in_file|, |out_file|, |validator_options|, and
  // |optimizer_options| are as in ParseFlags.
  //
  // This returns the same OptStatus instance returned by ParseFlags.
  OptStatus ParseOconfigFlag(const char* prog_name, const char* opt_flag,
                             spvtools::Optimizer* optimizer, const char** in_file,
                             const char** out_file,
                             spvtools::ValidatorOptions* validator_options,
                             spvtools::OptimizerOptions* optimizer_options) {
    std::vector<std::string> flags;
    flags.push_back(prog_name);
  
    std::vector<std::string> file_flags;
    if (!ReadFlagsFromFile(opt_flag, &file_flags)) {
      spvtools::Error(opt_diagnostic, nullptr, {},
                      "Could not read optimizer flags from configuration file");
      return {OPT_STOP, 1};
    }
    flags.insert(flags.end(), file_flags.begin(), file_flags.end());
  
    const char** new_argv = new const char*[flags.size()];
    for (size_t i = 0; i < flags.size(); i++) {
      if (flags[i].find("-Oconfig=") != std::string::npos) {
        spvtools::Error(
            opt_diagnostic, nullptr, {},
            "Flag -Oconfig= may not be used inside the configuration file");
        return {OPT_STOP, 1};
      }
      new_argv[i] = flags[i].c_str();
    }
  
    auto ret_val =
        ParseFlags(static_cast<int>(flags.size()), new_argv, optimizer, in_file,
                   out_file, validator_options, optimizer_options);
    delete[] new_argv;
    return ret_val;
  }
  
  // Canonicalize the flag in |argv[argi]| of the form '--pass arg' into
  // '--pass=arg'. The optimizer only accepts arguments to pass names that use the
  // form '--pass_name=arg'.  Since spirv-opt also accepts the other form, this
  // function makes the necessary conversion.
  //
  // Pass flags that require additional arguments should be handled here.  Note
  // that additional arguments should be given as a single string.  If the flag
  // requires more than one argument, the pass creator in
  // Optimizer::GetPassFromFlag() should parse it accordingly (e.g., see the
  // handler for --set-spec-const-default-value).
  //
  // If the argument requests one of the passes that need an additional argument,
  // |argi| is modified to point past the current argument, and the string
  // "argv[argi]=argv[argi + 1]" is returned. Otherwise, |argi| is unmodified and
  // the string "|argv[argi]|" is returned.
  std::string CanonicalizeFlag(const char** argv, int argc, int* argi) {
    const char* cur_arg = argv[*argi];
    const char* next_arg = (*argi + 1 < argc) ? argv[*argi + 1] : nullptr;
    std::ostringstream canonical_arg;
    canonical_arg << cur_arg;
  
    // NOTE: DO NOT ADD NEW FLAGS HERE.
    //
    // These flags are supported for backwards compatibility.  When adding new
    // passes that need extra arguments in its command-line flag, please make them
    // use the syntax "--pass_name[=pass_arg].
    if (0 == strcmp(cur_arg, "--set-spec-const-default-value") ||
        0 == strcmp(cur_arg, "--loop-fission") ||
        0 == strcmp(cur_arg, "--loop-fusion") ||
        0 == strcmp(cur_arg, "--loop-unroll-partial") ||
        0 == strcmp(cur_arg, "--loop-peeling-threshold")) {
      if (next_arg) {
        canonical_arg << "=" << next_arg;
        ++(*argi);
      }
    }
  
    return canonical_arg.str();
  }
  
  // Parses command-line flags. |argc| contains the number of command-line flags.
  // |argv| points to an array of strings holding the flags. |optimizer| is the
  // Optimizer instance used to optimize the program.
  //
  // On return, this function stores the name of the input program in |in_file|.
  // The name of the output file in |out_file|. The return value indicates whether
  // optimization should continue and a status code indicating an error or
  // success.
  OptStatus ParseFlags(int argc, const char** argv,
                       spvtools::Optimizer* optimizer, const char** in_file,
                       const char** out_file,
                       spvtools::ValidatorOptions* validator_options,
                       spvtools::OptimizerOptions* optimizer_options) {
    std::vector<std::string> pass_flags;
    bool target_env_set = false;
    bool vulkan_to_webgpu_set = false;
    bool webgpu_to_vulkan_set = false;
    for (int argi = 1; argi < argc; ++argi) {
      const char* cur_arg = argv[argi];
      if ('-' == cur_arg[0]) {
        if (0 == strcmp(cur_arg, "--version")) {
          spvtools::Logf(opt_diagnostic, SPV_MSG_INFO, nullptr, {}, "%s\n",
                         spvSoftwareVersionDetailsString());
          return {OPT_STOP, 0};
        } else if (0 == strcmp(cur_arg, "--help") || 0 == strcmp(cur_arg, "-h")) {
          PrintUsage(argv[0]);
          return {OPT_STOP, 0};
        } else if (0 == strcmp(cur_arg, "-o")) {
          if (!*out_file && argi + 1 < argc) {
            *out_file = argv[++argi];
          } else {
            PrintUsage(argv[0]);
            return {OPT_STOP, 1};
          }
        } else if ('\0' == cur_arg[1]) {
          // Setting a filename of "-" to indicate stdin.
          if (!*in_file) {
            *in_file = cur_arg;
          } else {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "More than one input file specified");
            return {OPT_STOP, 1};
          }
        } else if (0 == strncmp(cur_arg, "-Oconfig=", sizeof("-Oconfig=") - 1)) {
          OptStatus status =
              ParseOconfigFlag(argv[0], cur_arg, optimizer, in_file, out_file,
                               validator_options, optimizer_options);
          if (status.action != OPT_CONTINUE) {
            return status;
          }
        } else if (0 == strcmp(cur_arg, "--skip-validation")) {
          optimizer_options->set_run_validator(false);
        } else if (0 == strcmp(cur_arg, "--print-all")) {
          optimizer->SetPrintAll(&std::cerr);
        } else if (0 == strcmp(cur_arg, "--preserve-bindings")) {
          optimizer_options->set_preserve_bindings(true);
        } else if (0 == strcmp(cur_arg, "--preserve-spec-constants")) {
          optimizer_options->set_preserve_spec_constants(true);
        } else if (0 == strcmp(cur_arg, "--time-report")) {
          optimizer->SetTimeReport(&std::cerr);
        } else if (0 == strcmp(cur_arg, "--relax-struct-store")) {
          validator_options->SetRelaxStructStore(true);
        } else if (0 == strncmp(cur_arg, "--max-id-bound=",
                                sizeof("--max-id-bound=") - 1)) {
          auto split_flag = spvtools::utils::SplitFlagArgs(cur_arg);
          // Will not allow values in the range [2^31,2^32).
          uint32_t max_id_bound =
              static_cast<uint32_t>(atoi(split_flag.second.c_str()));
  
          // That SPIR-V mandates the minimum value for max id bound but
          // implementations may allow higher minimum bounds.
          if (max_id_bound < kDefaultMaxIdBound) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "The max id bound must be at least 0x3FFFFF");
            return {OPT_STOP, 1};
          }
          optimizer_options->set_max_id_bound(max_id_bound);
          validator_options->SetUniversalLimit(spv_validator_limit_max_id_bound,
                                               max_id_bound);
        } else if (0 == strncmp(cur_arg,
                                "--target-env=", sizeof("--target-env=") - 1)) {
          if (vulkan_to_webgpu_set) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "Cannot use both --vulkan-to-webgpu and --target-env "
                            "at the same time");
            return {OPT_STOP, 1};
          }
          if (webgpu_to_vulkan_set) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "Cannot use both --webgpu-to-vulkan and --target-env "
                            "at the same time");
            return {OPT_STOP, 1};
          }
          const auto split_flag = spvtools::utils::SplitFlagArgs(cur_arg);
          const auto target_env_str = split_flag.second.c_str();
          spv_target_env target_env;
          if (!spvParseTargetEnv(target_env_str, &target_env)) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "Invalid value passed to --target-env");
            return {OPT_STOP, 1};
          }
          optimizer->SetTargetEnv(target_env);
        } else if (0 == strcmp(cur_arg, "--vulkan-to-webgpu")) {
          if (target_env_set) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "Cannot use both --vulkan-to-webgpu and --target-env "
                            "at the same time");
            return {OPT_STOP, 1};
          }
          if (webgpu_to_vulkan_set) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "Cannot use both --vulkan-to-webgpu and "
                            "--webgpu-to-vulkan at the same time");
            return {OPT_STOP, 1};
          }
  
          optimizer->SetTargetEnv(SPV_ENV_WEBGPU_0);
          optimizer->RegisterVulkanToWebGPUPasses();
        } else if (0 == strcmp(cur_arg, "--webgpu-to-vulkan")) {
          if (target_env_set) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "Cannot use both --webgpu-to-vulkan and --target-env "
                            "at the same time");
            return {OPT_STOP, 1};
          }
          if (vulkan_to_webgpu_set) {
            spvtools::Error(opt_diagnostic, nullptr, {},
                            "Cannot use both --webgpu-to-vulkan and "
                            "--vulkan-to-webgpu at the same time");
            return {OPT_STOP, 1};
          }
  
          optimizer->SetTargetEnv(SPV_ENV_VULKAN_1_1);
          optimizer->RegisterWebGPUToVulkanPasses();
        } else if (0 == strcmp(cur_arg, "--validate-after-all")) {
          optimizer->SetValidateAfterAll(true);
        } else {
          // Some passes used to accept the form '--pass arg', canonicalize them
          // to '--pass=arg'.
          pass_flags.push_back(CanonicalizeFlag(argv, argc, &argi));
  
          // If we were requested to legalize SPIR-V generated from the HLSL
          // front-end, skip validation.
          if (0 == strcmp(cur_arg, "--legalize-hlsl")) {
            validator_options->SetBeforeHlslLegalization(true);
          }
        }
      } else {
        if (!*in_file) {
          *in_file = cur_arg;
        } else {
          spvtools::Error(opt_diagnostic, nullptr, {},
                          "More than one input file specified");
          return {OPT_STOP, 1};
        }
      }
    }
  
    if (!optimizer->RegisterPassesFromFlags(pass_flags)) {
      return {OPT_STOP, 1};
    }
  
    return {OPT_CONTINUE, 0};
  }
  
  }  // namespace
  
  int main(int argc, const char** argv) {
    const char* in_file = nullptr;
    const char* out_file = nullptr;
  
    spv_target_env target_env = kDefaultEnvironment;
  
    spvtools::Optimizer optimizer(target_env);
    optimizer.SetMessageConsumer(spvtools::utils::CLIMessageConsumer);
  
    spvtools::ValidatorOptions validator_options;
    spvtools::OptimizerOptions optimizer_options;
    OptStatus status = ParseFlags(argc, argv, &optimizer, &in_file, &out_file,
                                  &validator_options, &optimizer_options);
    optimizer_options.set_validator_options(validator_options);
  
    if (status.action == OPT_STOP) {
      return status.code;
    }
  
    if (out_file == nullptr) {
      spvtools::Error(opt_diagnostic, nullptr, {}, "-o required");
      return 1;
    }
  
    std::vector<uint32_t> binary;
    if (!ReadFile<uint32_t>(in_file, "rb", &binary)) {
      return 1;
    }
  
    // By using the same vector as input and output, we save time in the case
    // that there was no change.
    bool ok =
        optimizer.Run(binary.data(), binary.size(), &binary, optimizer_options);
  
    if (!WriteFile<uint32_t>(out_file, "wb", binary.data(), binary.size())) {
      return 1;
    }
  
    return ok ? 0 : 1;
  }
  