hlsl: Pointer support

Add `transform::InlinePointerLets` - a Transform that moves all usage of function-scope  `let` statements of a pointer type into their places of usage.

Make the HLSL writer transform pointer parameters to `inout`.

Fixed: tint:183
Change-Id: I0a7552fa6cd31c7b7691e64feae3170a81cc6c49
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/51281
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>

test/ptr_ref/access/matrix.spvasm.expected.hlsl

@@ -1 +1,8 @@
-SKIP: Failed to generate: error: pointers not supported in HLSL
+[numthreads(1, 1, 1)]
+void main() {
+  float3x3 m = float3x3(float3(0.0f, 0.0f, 0.0f), float3(0.0f, 0.0f, 0.0f), float3(0.0f, 0.0f, 0.0f));
+  m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
+  m[1] = float3(5.0f, 5.0f, 5.0f);
+  return;
+}
+

test/ptr_ref/access/matrix.wgsl.expected.hlsl

@@ -1 +1,7 @@
-SKIP: Failed to generate: error: pointers not supported in HLSL
+[numthreads(1, 1, 1)]
+void main() {
+  float3x3 m = float3x3(float3(1.0f, 2.0f, 3.0f), float3(4.0f, 5.0f, 6.0f), float3(7.0f, 8.0f, 9.0f));
+  m[1] = float3(5.0f, 5.0f, 5.0f);
+  return;
+}
+

test/ptr_ref/access/vector.spvasm.expected.hlsl

@@ -1 +1,8 @@
-SKIP: Failed to generate: error: pointers not supported in HLSL
+[numthreads(1, 1, 1)]
+void main() {
+  float3 v = float3(0.0f, 0.0f, 0.0f);
+  v = float3(1.0f, 2.0f, 3.0f);
+  v.y = 5.0f;
+  return;
+}
+

test/ptr_ref/access/vector.wgsl.expected.hlsl

@@ -1 +1,7 @@
-SKIP: Failed to generate: error: pointers not supported in HLSL
+[numthreads(1, 1, 1)]
+void main() {
+  float3 v = float3(1.0f, 2.0f, 3.0f);
+  v.y = 5.0f;
+  return;
+}
+

test/ptr_ref/copy/ptr_copy.spvasm.expected.hlsl

@@ -1 +1,6 @@
-SKIP: error: pointers not supported in HLSL
+[numthreads(1, 1, 1)]
+void main() {
+  uint x_10 = 0u;
+  return;
+}
+

test/ptr_ref/load/param/ptr.spvasm.expected.hlsl

@@ -1 +1,14 @@
-SKIP: error: pointers not supported in HLSL
+int func(int value, inout int pointer) {
+  const int x_9 = pointer;
+  return (value + x_9);
+}
+
+[numthreads(1, 1, 1)]
+void main() {
+  int i = 0;
+  i = 123;
+  const int x_19 = i;
+  const int x_18 = func(x_19, i);
+  return;
+}
+

test/ptr_ref/load/param/ptr.wgsl.expected.hlsl

@@ -1 +1,11 @@
-SKIP: error: pointers not supported in HLSL
+int func(int value, inout int pointer) {
+  return (value + pointer);
+}
+
+[numthreads(1, 1, 1)]
+void main() {
+  int i = 123;
+  const int r = func(i, i);
+  return;
+}
+

test/ptr_ref/store/local/i32.wgsl.expected.hlsl

@@ -1 +1,8 @@
-SKIP: Failed to generate: error: pointers not supported in HLSL
+[numthreads(1, 1, 1)]
+void main() {
+  int i = 123;
+  i = 123;
+  i = ((100 + 20) + 3);
+  return;
+}
+

test/ptr_ref/store/param/ptr.spvasm.expected.hlsl

@@ -1 +1,13 @@
-SKIP: error: pointers not supported in HLSL
+void func(int value, inout int pointer) {
+  pointer = value;
+  return;
+}
+
+[numthreads(1, 1, 1)]
+void main() {
+  int i = 0;
+  i = 123;
+  func(123, i);
+  return;
+}
+

test/ptr_ref/store/param/ptr.wgsl.expected.hlsl

@@ -1 +1,11 @@
-SKIP: error: pointers not supported in HLSL
+void func(int value, inout int pointer) {
+  pointer = value;
+}
+
+[numthreads(1, 1, 1)]
+void main() {
+  int i = 123;
+  func(123, i);
+  return;
+}
+