Reenable --skip-validation. (#1820)

In previous changes, the option `--skip-validation` was disabled.  This
change is to reenable it.

include/spirv-tools/optimizer.hpp

@@ -151,16 +151,22 @@ class Optimizer {
   // Optimizes the given SPIR-V module |original_binary| and writes the
   // optimized binary into |optimized_binary|.
   // Returns true on successful optimization, whether or not the module is
-  // modified. Returns false if errors occur when processing |original_binary|
-  // using any of the registered passes. In that case, no further passes are
-  // executed and the contents in |optimized_binary| may be invalid.
+  // modified. Returns false if |original_binary| fails to validate or if errors
+  // occur when processing |original_binary| using any of the registered passes.
+  // In that case, no further passes are executed and the contents in
+  // |optimized_binary| may be invalid.
   //
   // It's allowed to alias |original_binary| to the start of |optimized_binary|.
   bool Run(const uint32_t* original_binary, size_t original_binary_size,
            std::vector<uint32_t>* optimized_binary) const;
-  bool Run(const uint32_t* original_binary, size_t original_binary_size,
+
+  // Same as above, except passes |options| to the validator when trying to
+  // validate the binary.  If |skip_validation| is true, then the caller is
+  // guaranteeing that |original_binary| is valid, and the validator will not
+  // be run.
+  bool Run(const uint32_t* original_binary, const size_t original_binary_size,
            std::vector<uint32_t>* optimized_binary,
-           const ValidatorOptions& options) const;
+           const ValidatorOptions& options, bool skip_validation = false) const;
 
   // Returns a vector of strings with all the pass names added to this
   // optimizer's pass manager. These strings are valid until the associated

source/opt/optimizer.cpp

@@ -455,10 +455,12 @@ bool Optimizer::Run(const uint32_t* original_binary,
 bool Optimizer::Run(const uint32_t* original_binary,
                     const size_t original_binary_size,
                     std::vector<uint32_t>* optimized_binary,
-                    const ValidatorOptions& options) const {
+                    const ValidatorOptions& options,
+                    bool skip_validation) const {
   spvtools::SpirvTools tools(impl_->target_env);
   tools.SetMessageConsumer(impl_->pass_manager.consumer());
-  if (!tools.Validate(original_binary, original_binary_size, options)) {
+  if (!skip_validation &&
+      !tools.Validate(original_binary, original_binary_size, options)) {
     return false;
   }
 

tools/opt/opt.cpp

@@ -590,7 +590,8 @@ int main(int argc, const char** argv) {
 
   // 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, options);
+  bool ok = optimizer.Run(binary.data(), binary.size(), &binary, options,
+                          skip_validator);
 
   if (!WriteFile<uint32_t>(out_file, "wb", binary.data(), binary.size())) {
     return 1;