From 2c445380b1e3b3c0e18a332d70c4c845ec715e67 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Fri, 20 Sep 2024 14:03:03 +0900
Subject: [PATCH] [qfcc] Emit extensions and extinst imports

The imports need their result id recorded somewhere (and the hard-coding
in qc-parse.y removed), but that's a little bit of progress getting
spir-v working.
---
 tools/qfcc/include/spirv.h   |  2 ++
 tools/qfcc/source/qc-parse.y |  3 ++
 tools/qfcc/source/spirv.c    | 53 +++++++++++++++++++++++++++++++++---
 3 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/tools/qfcc/include/spirv.h b/tools/qfcc/include/spirv.h
index 89f69d31a..125036af9 100644
--- a/tools/qfcc/include/spirv.h
+++ b/tools/qfcc/include/spirv.h
@@ -57,6 +57,8 @@ typedef struct module_s {
 } module_t;
 
 void spirv_add_capability (module_t *module, SpvCapability capability);
+void spirv_add_extension (module_t *module, const char *extension);
+void spirv_add_extinst_import (module_t *module, const char *import);
 void spirv_set_addressing_model (module_t *module, SpvAddressingModel model);
 void spirv_set_memory_model (module_t *module, SpvMemoryModel model);
 bool spirv_write (struct pr_info_s *pr, const char *filename);
diff --git a/tools/qfcc/source/qc-parse.y b/tools/qfcc/source/qc-parse.y
index 6ca6f5094..c4c329937 100644
--- a/tools/qfcc/source/qc-parse.y
+++ b/tools/qfcc/source/qc-parse.y
@@ -3096,6 +3096,9 @@ rua_init (void)
 		pr.module = &module;
 
 		spirv_add_capability (pr.module, SpvCapabilityShader);
+		//FIXME unhardcode
+		spirv_add_extension (pr.module, "SPV_KHR_multiview");
+		spirv_add_extinst_import (pr.module, "GLSL.std.450");
 		//FIXME sufficient? phys 32/storage?
 		spirv_set_addressing_model (pr.module, SpvAddressingModelLogical);
 		//FIXME look into Vulkan, or even configurable
diff --git a/tools/qfcc/source/spirv.c b/tools/qfcc/source/spirv.c
index 67cd6b638..adb0612ec 100644
--- a/tools/qfcc/source/spirv.c
+++ b/tools/qfcc/source/spirv.c
@@ -64,6 +64,18 @@ spirv_new_insn (int op, int size, defspace_t *space)
 	return def;
 }
 
+static def_t *
+spirv_str_insn (int op, int offs, int extra, const char *str, defspace_t *space)
+{
+	int len = strlen (str) + 1;
+	int str_size = RUP(len, 4) / 4;
+	int size = offs + str_size + extra;
+	auto def = spirv_new_insn (op, size, space);
+	D_var_o(int, def, str_size - 1) = 0;
+	memcpy (&D_var_o(int, def, offs), str, len);
+	return def;
+}
+
 static unsigned
 spirv_id (spirvctx_t *ctx)
 {
@@ -77,6 +89,21 @@ spirv_Capability (SpvCapability capability, defspace_t *space)
 	D_var_o(int, def, 1) = capability;
 }
 
+static void
+spirv_Extension (const char *ext, defspace_t *space)
+{
+	spirv_str_insn (SpvOpExtension, 1, 0, ext, space);
+}
+
+static unsigned
+spirv_ExtInstImport (const char *imp, spirvctx_t *ctx)
+{
+	auto def = spirv_str_insn (SpvOpExtInstImport, 2, 0, imp, ctx->space);
+	int id = spirv_id (ctx);
+	D_var_o(int, def, 1) = id;
+	return id;
+}
+
 static void
 spirv_MemoryModel (SpvAddressingModel addressing, SpvMemoryModel memory,
 				   defspace_t *space)
@@ -89,11 +116,9 @@ spirv_MemoryModel (SpvAddressingModel addressing, SpvMemoryModel memory,
 static unsigned
 spirv_String (const char *name, spirvctx_t *ctx)
 {
+	auto def = spirv_str_insn (SpvOpString, 2, 0, name, ctx->strings);
 	int id = spirv_id (ctx);
-	int len = strlen (name) + 1;
-	auto def = spirv_new_insn (SpvOpString, 2 + RUP(len, 4) / 4, ctx->strings);
 	D_var_o(int, def, 1) = id;
-	memcpy (&D_var_o(int, def, 2), name, len);
 	return id;
 }
 
@@ -410,8 +435,14 @@ spirv_write (struct pr_info_s *pr, const char *filename)
 	for (auto cap = pr->module->capabilities.head; cap; cap = cap->next) {
 		spirv_Capability (expr_uint (cap->expr), ctx.space);
 	}
+	for (auto ext = pr->module->extensions.head; ext; ext = ext->next) {
+		spirv_Extension (expr_string (ext->expr), ctx.space);
+	}
+	for (auto imp = pr->module->extinst_imports.head; imp; imp = imp->next) {
+		//FIXME need to store id where it can be used for instructions
+		spirv_ExtInstImport (expr_string (imp->expr), &ctx);
+	}
 
-	//FIXME none of these should be hard-coded
 	spirv_MemoryModel (expr_uint (pr->module->addressing_model),
 					   expr_uint (pr->module->memory_model), ctx.space);
 
@@ -450,6 +481,20 @@ spirv_add_capability (module_t *module, SpvCapability capability)
 	list_append (&module->capabilities, cap);
 }
 
+void
+spirv_add_extension (module_t *module, const char *extension)
+{
+	auto ext = new_string_expr (extension);
+	list_append (&module->extensions, ext);
+}
+
+void
+spirv_add_extinst_import (module_t *module, const char *import)
+{
+	auto imp = new_string_expr (import);
+	list_append (&module->extinst_imports, imp);
+}
+
 void
 spirv_set_addressing_model (module_t *module, SpvAddressingModel model)
 {