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, 10 insertions, 0 deletions

diff --git a/tests/library/module-library-pointer-param.slang b/tests/library/module-library-pointer-param.slang
new file mode 100644
index 000000000..fff4f67c6
--- /dev/null
+++ b/tests/library/module-library-pointer-param.slang
@@ -0,0 +1,10 @@
+//TEST_IGNORE_FILE:
+
+// module-library-pointer-param.slang
+
+module "module-library-pointer-param";
+
+public int ptrFunc(int* a)
+{
+    return *a;
+}