[ir][spirv-writer] Emit store instructions

Bug: tint:1906
Change-Id: I858e619fe2968ebe2708d0d47c12b0c17b20cc31
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/133224
Commit-Queue: James Price <jrprice@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>

src/tint/writer/spirv/ir/generator_impl_ir.cc

@@ -20,6 +20,7 @@
 #include "src/tint/ir/function_terminator.h"
 #include "src/tint/ir/if.h"
 #include "src/tint/ir/module.h"
+#include "src/tint/ir/store.h"
 #include "src/tint/ir/transform/add_empty_entry_point.h"
 #include "src/tint/ir/var.h"
 #include "src/tint/switch.h"
@@ -295,6 +296,10 @@ void GeneratorImplIr::EmitBlock(const ir::Block* block) {
         auto result = Switch(
             inst,  //
             [&](const ir::Binary* b) { return EmitBinary(b); },
+            [&](const ir::Store* s) {
+                EmitStore(s);
+                return 0u;
+            },
             [&](const ir::Var* v) { return EmitVar(v); },
             [&](Default) {
                 TINT_ICE(Writer, diagnostics_)
@@ -391,6 +396,10 @@ uint32_t GeneratorImplIr::EmitBinary(const ir::Binary* binary) {
     return id;
 }
 
+void GeneratorImplIr::EmitStore(const ir::Store* store) {
+    current_function_.push_inst(spv::Op::OpStore, {Value(store->to), Value(store->from)});
+}
+
 uint32_t GeneratorImplIr::EmitVar(const ir::Var* var) {
     auto id = module_.NextId();
     auto* ptr = var->Type()->As<type::Pointer>();

src/tint/writer/spirv/ir/generator_impl_ir.h

@@ -33,6 +33,7 @@ class Block;
 class If;
 class Function;
 class Module;
+class Store;
 class Value;
 class Var;
 }  // namespace tint::ir
@@ -105,6 +106,10 @@ class GeneratorImplIr {
     /// @returns the result ID of the instruction
     uint32_t EmitBinary(const ir::Binary* binary);
 
+    /// Emit a store instruction.
+    /// @param store the store instruction to emit
+    void EmitStore(const ir::Store* store);
+
     /// Emit a var instruction.
     /// @param var the var instruction to emit
     /// @returns the result ID of the instruction

src/tint/writer/spirv/ir/generator_impl_ir_var_test.cc

@@ -138,5 +138,31 @@ OpFunctionEnd
 )");
 }
 
+TEST_F(SpvGeneratorImplTest, FunctionVar_Store) {
+    auto* func = b.CreateFunction(mod.symbols.Register("foo"), mod.types.Get<type::Void>());
+    b.Branch(func->start_target, func->end_target);
+
+    auto* ty = mod.types.Get<type::Pointer>(
+        mod.types.Get<type::I32>(), builtin::AddressSpace::kFunction, builtin::Access::kReadWrite);
+    auto* v = b.Declare(ty);
+    func->start_target->instructions.Push(v);
+    func->start_target->instructions.Push(b.Store(v, b.Constant(42_i)));
+
+    generator_.EmitFunction(func);
+    EXPECT_EQ(DumpModule(generator_.Module()), R"(OpName %1 "foo"
+%2 = OpTypeVoid
+%3 = OpTypeFunction %2
+%7 = OpTypeInt 32 1
+%6 = OpTypePointer Function %7
+%8 = OpConstant %7 42
+%1 = OpFunction %2 None %3
+%4 = OpLabel
+%5 = OpVariable %6 Function
+OpStore %5 %8
+OpReturn
+OpFunctionEnd
+)");
+}
+
 }  // namespace
 }  // namespace tint::writer::spirv