Implement notion of a "container format" (#213)

The big addition here is that the Slang "bytecode" is no longer treated as just a "code generation target" (`CodeGenTarget`) akin to DX bytecode (DXBC) or SPIR-V, but instead is a `ContainerFormat` that can be used to emit all the results of a compile request (well, currently just the IR-as-BC, but the intention is there).

Getting to this goal involved some prior checkins that eliminated bogus "targets" that weren't really akin to SPIR-V or DXBC: `-target slang-ir-asm` and `-target reflection-json`. Those targets were really in place to support testing, and so they've been made more explicit testing/debug options.

This change eliminates `-target slang-ir` and instead tries to allow the user to specify `-o foo.slang-module` as an output file name, that indicates the intention to output a "container" file that will wrap up all the generated code.

I've also gone ahead and generalized the existing `-target` option so that we are actually building up a *list* of code generation targets. This is largely just a cleanup, since it forces code to be more aware of when it is doing something target-specific vs. target independent. For example, reflection layout information lives on a requested target, and not on the compile request as a whole, and similarly output code is per-target, per-entry-point.

As a cleanup, I eliminated support for per-translation-unit output. This was vestigial code from back when I used to try and do HLSL generation for a whole translation unit instead of per-entry-point (which turned out to be a lot of complexity for little gain), and it was only being used in the `hello` example and the `render-test` test fixture - in both cases fixing it up was easy enough. I've stubbed out the old `spGetTranslationUnitSource` API, but haven't removed it yet.

1 files changed, 14 insertions, 22 deletions

diff --git a/source/slang/reflection.cpp b/source/slang/reflection.cpp
index 3ef3effab..435b4db3f 100644
--- a/source/slang/reflection.cpp
+++ b/source/slang/reflection.cpp
@@ -798,23 +798,22 @@ SLANG_API int spReflectionEntryPoint_usesAnySampleRateInput(
 
 // Shader Reflection
 
+namespace Slang
+{
+    StructTypeLayout* getGlobalStructLayout(
+        ProgramLayout*  programLayout);
+}
+
 SLANG_API unsigned spReflection_GetParameterCount(SlangReflection* inProgram)
 {
     auto program = convert(inProgram);
     if(!program) return 0;
 
-    auto globalLayout = program->globalScopeLayout;
-    if(auto globalConstantBufferLayout = globalLayout.As<ParameterBlockTypeLayout>())
-    {
-        globalLayout = globalConstantBufferLayout->elementTypeLayout;
-    }
-
-    if(auto globalStructLayout = globalLayout.As<StructTypeLayout>())
-    {
-        return (unsigned) globalStructLayout->fields.Count();
-    }
+    auto globalStructLayout = getGlobalStructLayout(program);
+    if (!globalStructLayout)
+        return 0;
 
-    return 0;
+    return (unsigned) globalStructLayout->fields.Count();
 }
 
 SLANG_API SlangReflectionParameter* spReflection_GetParameterByIndex(SlangReflection* inProgram, unsigned index)
@@ -822,18 +821,11 @@ SLANG_API SlangReflectionParameter* spReflection_GetParameterByIndex(SlangReflec
     auto program = convert(inProgram);
     if(!program) return nullptr;
 
-    auto globalLayout = program->globalScopeLayout;
-    if(auto globalConstantBufferLayout = globalLayout.As<ParameterBlockTypeLayout>())
-    {
-        globalLayout = globalConstantBufferLayout->elementTypeLayout;
-    }
-
-    if(auto globalStructLayout = globalLayout.As<StructTypeLayout>())
-    {
-        return convert(globalStructLayout->fields[index].Ptr());
-    }
+    auto globalStructLayout = getGlobalStructLayout(program);
+    if (!globalStructLayout)
+        return 0;
 
-    return nullptr;
+    return convert(globalStructLayout->fields[index].Ptr());
 }
 
 SLANG_API SlangUInt spReflection_getEntryPointCount(SlangReflection* inProgram)