Precompiled SPIR-V import support (#5048)

* Precompiled SPIR-V import support

Adds appropriate linkage and function declaration syntax
for SPIR-V functions that are declared, to be imported
from another SPIR-V module.

Unlike DXIL, stripping the Slang IR for a function down
to a declaration requires retaining a block of parameters,
as the function declaration must be emitted to SPIR-V
with the same parameters as a definition. Because that
thwarts the logic in Slang to tell the difference between
a declaration and definition, and explicit decoration is
introduced to explicitly mark functions which need to be
treated as declarations during emit phase.

Fixes #4992

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/tests/library/precompiled-spirv-pointer-param.slang b/tests/library/precompiled-spirv-pointer-param.slang
new file mode 100644
index 000000000..10cd7124b
--- /dev/null
+++ b/tests/library/precompiled-spirv-pointer-param.slang
@@ -0,0 +1,31 @@
+// precompiled-spirv-pointer-param.slang
+
+// A test that uses slang-modules with embedded precompiled SPIRV and a library containing 
+// a function with a pointer parameter.
+// The test compiles a library slang (module-library-pointer-param.slang) with -embed-downstream-ir then links the
+// library to entrypoint slang (this file).
+// The test passes if there is no errror thrown.
+// TODO: Check if final linkage used only the precompiled spirv.
+
+//TEST:COMPILE: tests/library/module-library-pointer-param.slang -o tests/library/module-library-pointer-param.slang-module -target spirv -embed-downstream-ir -incomplete-library
+//TEST:COMPILE: tests/library/precompiled-spirv-pointer-param.slang -target spirv -stage anyhit -entry anyhit -o tests/library/linked.spirv
+
+import "module-library-pointer-param";
+
+struct Payload
+{
+    int val;
+}
+
+struct Attributes
+{
+    float2 bary;
+}
+
+[vk::push_constant] int* g_int;
+
+[shader("anyhit")]
+void anyhit(inout Payload payload, Attributes attrib)
+{
+    payload.val = ptrFunc(g_int);
+}