From 41247c3942210df33b9e3dd733eafb23573a4f2f Mon Sep 17 00:00:00 2001
From: jsmall-nvidia <jsmall@nvidia.com>
Date: Thu, 8 Aug 2019 17:23:03 -0400
Subject: WIP: Preliminary Slang -> C++ code generation (#1009)

* Expanded prelude for some other resource types. Disable C++ output for ParameterGroup.

* WIP: Layout for CPU.

* Fixes to CPU layout.

* WIP: The uniform is output, but the variable definition is not.

* WIP: Entry point parameters to global scope in C++.
Handling of resource types (in so far as outputting)

* Some discussion of ABI and different input types.

* WIP: More C++ support around resource types.

* WIP: Split up variables into different structures on emit.

* WIP: Emitting C++ with wrapping up of 'Context'

* WIP: C++ code has access to semantic values.
Wrap in struct so can use method calls to pass shared state.
Disable  legalizeResourceTypes and legalizeExistentialTypeLayout

* Fix structured buffer layout for CPU.

* Remove testing/handling of global uniforms on CPU path.
Typo fix.
Changed CPU tests to use new CPU calling convention.

* Check globals are working. Initalize context to zero globals.

* Order the global parameters for C++ ouput by their layout.
Note - that layout isn't quite working correctly because the StructuredBuffer<int> the int seems to be consuming uniform space.

* Work around for reflection not having all data needed for layout ordering for C++ code.

* Output constant buffers as pointers.

* Entry point parameters accessed through pointer to struct.

* WIP: Layout for CPU is reasonable for test case.

* Only output 'f' after float literal if type marks as a float.

* Cast construction works on C++.

* Made IntrinsicOp::ConvertConstruct to make intent clearer.

* C++ handling construction from scalar.
Handle access of a scalar with .x.
Check default initialization.

* Comment about need for split of kIROp_construct.
Release build works.

* Added support from constructVectorFromScalar to C/C++ target.

* Handling of in/out in C/C++.

* First pass documentation CPU support.

* Improvements to C++/C slang code generation documentation.

* Small doc change to include need for mechansim to specify cpp compiler path.

* Better handling of swizzling - allow swizzling a scalar into a vector.
---
 source/slang/slang-parameter-binding.cpp | 37 +++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 8 deletions(-)

(limited to 'source/slang/slang-parameter-binding.cpp')

diff --git a/source/slang/slang-parameter-binding.cpp b/source/slang/slang-parameter-binding.cpp
index 722725af7..f9657e776 100644
--- a/source/slang/slang-parameter-binding.cpp
+++ b/source/slang/slang-parameter-binding.cpp
@@ -2632,6 +2632,21 @@ static int _calcTotalNumUsedRegistersForLayoutResourceKind(ParameterBindingConte
     return numUsed;
 }
 
+static bool _isCPUTarget(CodeGenTarget target)
+{
+    switch (target)
+    {
+        case CodeGenTarget::CPPSource:
+        case CodeGenTarget::CSource:
+        case CodeGenTarget::Executable:
+        case CodeGenTarget::SharedLibrary:
+        {
+            return true;
+        }
+        default: return false;
+    }
+}
+
     /// Keep track of the running global counter for entry points and global parameters visited.
     ///
     /// Because of explicit `register` and `[[vk::binding(...)]]` support, parameter binding
@@ -3022,16 +3037,22 @@ RefPtr<ProgramLayout> generateParameterBindings(
     // want to do so through a different feature.
     //
     bool needDefaultConstantBuffer = false;
-    for( auto& parameterInfo : sharedContext.parameters )
-    {
-        SLANG_RELEASE_ASSERT(parameterInfo->varLayouts.getCount() != 0);
-        auto firstVarLayout = parameterInfo->varLayouts.getFirst();
 
-        // Does the field have any uniform data?
-        if( firstVarLayout->typeLayout->FindResourceInfo(LayoutResourceKind::Uniform) )
+    // On a CPU target, it's okay to have global scope parameters that use Uniform resources (because on CPU
+    // all resources are 'Uniform')
+    if (!_isCPUTarget(targetReq->target))
+    {
+        for( auto& parameterInfo : sharedContext.parameters )
         {
-            needDefaultConstantBuffer = true;
-            diagnoseGlobalUniform(&sharedContext, firstVarLayout->varDecl);
+            SLANG_RELEASE_ASSERT(parameterInfo->varLayouts.getCount() != 0);
+            auto firstVarLayout = parameterInfo->varLayouts.getFirst();
+
+            // Does the field have any uniform data?
+            if( firstVarLayout->typeLayout->FindResourceInfo(LayoutResourceKind::Uniform) )
+            {
+                needDefaultConstantBuffer = true;
+                diagnoseGlobalUniform(&sharedContext, firstVarLayout->varDecl);
+            }
         }
     }
 
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