HLSL: Add location offsets per resource type

This PR adds the ability to offset sampler, texture, and UBO bindings
from provided base bindings, and to auto-number bindings that are not
provided with explicit register numbers. The mechanism works as
follows:

- Offsets may be given on the command line for all stages, or
  individually for one or more single stages, in which case the
  offset will be auto-selected according to the stage being
  compiled. There is also an API to set them. The new command line
  options are --shift-sampler-binding, --shift-texture-binding, and
  --shift-UBO-binding.

- Uniforms which are not given explicit bindings in the source code
  are auto-numbered if and only if they are in live code as
  determined by the algorithm used to build the reflection
  database, and the --auto-map-bindings option is given. This auto-numbering
  avoids using any binding slots which were explicitly provided in
  the code, whether or not that explicit use was live. E.g, "uniform
  Texture1D foo : register(t3);" with --shift-texture-binding 10 will
  reserve binding 13, whether or not foo is used in live code.

- Shorter synonyms for the command line options are available.  See
  the --help output.

The testing infrastructure is slightly extended to allow use of the
binding offset API, and two new tests spv.register.(no)autoassign.frag are
added for comparing the resulting SPIR-V.

gtests/Spv.FromFile.cpp

@@ -41,11 +41,30 @@
 namespace glslangtest {
 namespace {
 
+struct IoMapData {
+    const char* fileName;
+    const char* entryPoint;
+    int baseSamplerBinding;
+    int baseTextureBinding;
+    int baseUboBinding;
+    bool autoMapBindings;
+};
+
+std::string FileNameAsCustomTestSuffixIoMap(
+    const ::testing::TestParamInfo<IoMapData>& info) {
+    std::string name = info.param.fileName;
+    // A valid test case suffix cannot have '.' and '-' inside.
+    std::replace(name.begin(), name.end(), '.', '_');
+    std::replace(name.begin(), name.end(), '-', '_');
+    return name;
+}
+
 using CompileVulkanToSpirvTest = GlslangTest<::testing::TestWithParam<std::string>>;
 using CompileOpenGLToSpirvTest = GlslangTest<::testing::TestWithParam<std::string>>;
 using VulkanSemantics = GlslangTest<::testing::TestWithParam<std::string>>;
 using OpenGLSemantics = GlslangTest<::testing::TestWithParam<std::string>>;
 using VulkanAstSemantics = GlslangTest<::testing::TestWithParam<std::string>>;
+using HlslSemantics = GlslangTest<::testing::TestWithParam<IoMapData>>;
 
 // Compiling GLSL to SPIR-V under Vulkan semantics. Expected to successfully
 // generate SPIR-V.
@@ -91,6 +110,18 @@ TEST_P(VulkanAstSemantics, FromFile)
                             Target::AST);
 }
 
+// HLSL-level Vulkan semantics tests.
+TEST_P(HlslSemantics, FromFile)
+{
+    loadFileCompileIoMapAndCheck(GLSLANG_TEST_DIRECTORY, GetParam().fileName,
+                                 Source::HLSL, Semantics::Vulkan,
+                                 Target::Spv, GetParam().entryPoint,
+                                 GetParam().baseSamplerBinding,
+                                 GetParam().baseTextureBinding,
+                                 GetParam().baseUboBinding,
+                                 GetParam().autoMapBindings);
+}
+
 // clang-format off
 INSTANTIATE_TEST_CASE_P(
     Glsl, CompileVulkanToSpirvTest,
@@ -216,6 +247,16 @@ INSTANTIATE_TEST_CASE_P(
     FileNameAsCustomTestSuffix
 );
 
+// clang-format off
+INSTANTIATE_TEST_CASE_P(
+    Hlsl, HlslSemantics,
+    ::testing::ValuesIn(std::vector<IoMapData>{
+        { "spv.register.autoassign.frag", "main_ep", 5, 10, 15, true },
+        { "spv.register.noautoassign.frag", "main_ep", 5, 10, 15, false },
+    }),
+    FileNameAsCustomTestSuffixIoMap
+);
+
 // clang-format off
 INSTANTIATE_TEST_CASE_P(
     Glsl, CompileOpenGLToSpirvTest,