Update the legalization passes.

Changes the set of optimizations done for legalization.  While doing
this, I added documentation to explain why we want each optimization.

A new option "--legalize-hlsl" is added so the legalization passes can
be easily run from the command line.
The legalize option implies skip-validation.

1 files changed, 19 insertions, 2 deletions

diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 34ab4cb1..1eab922e 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -48,6 +48,12 @@ std::string GetListOfPassesAsString(const spvtools::Optimizer& optimizer) {
   return ss.str();
 }
 
+std::string GetLegalizationPasses() {
+  spvtools::Optimizer optimizer(SPV_ENV_UNIVERSAL_1_2);
+  optimizer.RegisterLegalizationPasses();
+  return GetListOfPassesAsString(optimizer);
+}
+
 std::string GetOptimizationPasses() {
   spvtools::Optimizer optimizer(SPV_ENV_UNIVERSAL_1_2);
   optimizer.RegisterPerformancePasses();
@@ -140,6 +146,14 @@ Options (in lexicographical order):
                Exhaustively inline all function calls in entry point call tree
                functions. Currently does not inline calls to functions with
                early return in a loop.
+  --legalize-hlsl
+               Runs a series of optimizations that attempts to take SPIR-V
+               generated by and HLSL front-end and generate legal Vulkan SPIR-V.
+               The optimizations are:
+               %s
+
+               Note this does not guarantee legal code. This option implies
+               --skip-validation.
   --local-redundancy-elimination
                Looks for instructions in the same basic block that compute the
                same value, and deletes the redundant ones.
@@ -234,8 +248,8 @@ Options (in lexicographical order):
   --version
                Display optimizer version information.
 )",
-      program, program, GetOptimizationPasses().c_str(),
-      GetSizePasses().c_str());
+      program, program, GetLegalizationPasses().c_str(),
+      GetOptimizationPasses().c_str(), GetSizePasses().c_str());
 }
 
 // Reads command-line flags  the file specified in |oconfig_flag|. This string
@@ -421,6 +435,9 @@ OptStatus ParseFlags(int argc, const char** argv, Optimizer* optimizer,
         optimizer->RegisterPerformancePasses();
       } else if (0 == strcmp(cur_arg, "-Os")) {
         optimizer->RegisterSizePasses();
+      } else if (0 == strcmp(cur_arg, "--legalize-hlsl")) {
+        *skip_validator = true;
+        optimizer->RegisterLegalizationPasses();
       } else if (0 == strncmp(cur_arg, "-Oconfig=", sizeof("-Oconfig=") - 1)) {
         OptStatus status =
             ParseOconfigFlag(argv[0], cur_arg, optimizer, in_file, out_file);