Anastasia added inline comments.
================
Comment at: clang/lib/CodeGen/CGHLSLRuntime.cpp:61
+
+GlobalVariable *replaceCBuffer(CGHLSLRuntime::CBuffer &CB) {
+ const unsigned CBufferAddressSpace = 4;
----------------
python3kgae wrote:
> Anastasia wrote:
> > I don't think I understand the intent of this function along with
> > `CGHLSLRuntime::addConstant` that populates this collection.
> It is translating
>
> ```
> cbuffer A {
> float a;
> float b;
> }
> float foo() {
> return a + b;
> }
> ```
> into
>
> ```
> struct cb.A.Ty {
> float a;
> float b;
> };
>
> cbuffer A {
> cb.A.Ty CBA;
> }
> float foo() {
> return CBA.a + CBA.b;
> }
> ```
>
> Both a and b are in the global scope and will get a GlobalVariable in clang
> codeGen.
> By doing the translation, we can ensure each buffer map to one GlobalVariable
> and save cbuffer layout in the value type of that GlobalVariable.
Ok, I see, so if we are to translate it to C it would be something similar to:
```
struct A {
float a;
float b;
} cbuffer_A __attribute__((address_space(256)));
float foo() {
return cbuffer_A.a + cbuffer_A.b;
}
```
Maybe you can add some comments to explain the intent of this code at a higher
level... not sure if the generation can reuse or be made a bit close to the
regular C structs + address spaces...
================
Comment at: clang/lib/CodeGen/CGHLSLRuntime.cpp:119
+void CGHLSLRuntime::addConstant(VarDecl *D, Buffer &CB) {
+ if (D->getStorageClass() == SC_Static) {
+ // For static inside cbuffer, take as global static.
----------------
btw is this covered in the test?
================
Comment at: clang/lib/CodeGen/CGHLSLRuntime.cpp:152
+ // as it only refers to globally scoped declarations.
+ CGM.EmitTopLevelDecl(it);
+ } else if (NamespaceDecl *ND = dyn_cast<NamespaceDecl>(it)) {
----------------
Ok I think you don't have this in the tests too and the one below?
================
Comment at: clang/lib/CodeGen/CGHLSLRuntime.cpp:183
+ const unsigned CBufferAddressSpace =
+ ASMap[(unsigned)clang::LangAS::hlsl_cbuffer];
+ const unsigned TBufferAddressSpace =
----------------
I think it's better to use `getTargetAddressSpace` from `ASTContext`.
================
Comment at: clang/test/CodeGenHLSL/nest_cbuf.hlsl:8
+ // CHECK: @[[TB:.+]] = external addrspace(5) constant { float, i32, double }
+ tbuffer A : register(t2, space1) {
+ float c;
----------------
is this generated as nested structs?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D130131/new/
https://reviews.llvm.org/D130131
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