writer/wgsl: Implement interpolate attributes Add E2E tests to cover all of the parameter combinations. Mark the attribute as unimplemented in the other backends. Bug: tint:746 Change-Id: I86881ff0b224fe93670db42473341ae185eeabdd Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/56244 Kokoro: Kokoro <noreply+kokoro@google.com> Auto-Submit: James Price <jrprice@google.com> Reviewed-by: Ben Clayton <bclayton@google.com>

diff --git a/src/writer/hlsl/generator_impl.cc b/src/writer/hlsl/generator_impl.cc
index 496be2d..0c0c474 100644
--- a/src/writer/hlsl/generator_impl.cc
+++ b/src/writer/hlsl/generator_impl.cc

@@ -23,6 +23,7 @@
 #include "src/ast/call_statement.h"
 #include "src/ast/fallthrough_statement.h"
 #include "src/ast/internal_decoration.h"
+#include "src/ast/interpolate_decoration.h"
 #include "src/ast/override_decoration.h"
 #include "src/ast/variable_decl_statement.h"
 #include "src/sem/array.h"
@@ -2772,6 +2773,8 @@
             return false;
           }
           out << " : " << attr;
+        } else if (deco->Is<ast::InterpolateDecoration>()) {
+          TINT_UNIMPLEMENTED(Writer, diagnostics_) << "interpolate decoration";
         }
       }
 

diff --git a/src/writer/msl/generator_impl.cc b/src/writer/msl/generator_impl.cc
index c1c73b2..271da3b 100644
--- a/src/writer/msl/generator_impl.cc
+++ b/src/writer/msl/generator_impl.cc

@@ -25,6 +25,7 @@
 #include "src/ast/disable_validation_decoration.h"
 #include "src/ast/fallthrough_statement.h"
 #include "src/ast/float_literal.h"
+#include "src/ast/interpolate_decoration.h"
 #include "src/ast/module.h"
 #include "src/ast/override_decoration.h"
 #include "src/ast/sint_literal.h"
@@ -1783,6 +1784,8 @@
           TINT_ICE(Writer, diagnostics_)
               << "invalid use of location decoration";
         }
+      } else if (deco->Is<ast::InterpolateDecoration>()) {
+        TINT_UNIMPLEMENTED(Writer, diagnostics_) << "interpolate decoration";
       }
     }
 

diff --git a/src/writer/wgsl/generator_impl.cc b/src/writer/wgsl/generator_impl.cc
index 82875c4..42785a8 100644
--- a/src/writer/wgsl/generator_impl.cc
+++ b/src/writer/wgsl/generator_impl.cc

@@ -30,6 +30,7 @@
 #include "src/ast/float_literal.h"
 #include "src/ast/i32.h"
 #include "src/ast/internal_decoration.h"
+#include "src/ast/interpolate_decoration.h"
 #include "src/ast/matrix.h"
 #include "src/ast/module.h"
 #include "src/ast/multisampled_texture.h"
@@ -668,6 +669,12 @@
       out_ << "location(" << location->value() << ")";
     } else if (auto* builtin = deco->As<ast::BuiltinDecoration>()) {
       out_ << "builtin(" << builtin->value() << ")";
+    } else if (auto* interpolate = deco->As<ast::InterpolateDecoration>()) {
+      out_ << "interpolate(" << interpolate->type();
+      if (interpolate->sampling() != ast::InterpolationSampling::kNone) {
+        out_ << ", " << interpolate->sampling();
+      }
+      out_ << ")";
     } else if (auto* override_deco = deco->As<ast::OverrideDecoration>()) {
       out_ << "override";
       if (override_deco->HasValue()) {

diff --git a/test/shader_io/interpolate_input_parameters.wgsl b/test/shader_io/interpolate_input_parameters.wgsl
new file mode 100644
index 0000000..64556cd
--- /dev/null
+++ b/test/shader_io/interpolate_input_parameters.wgsl

@@ -0,0 +1,11 @@
+[[stage(fragment)]]
+fn main(
+  [[location(0)]] none : f32,
+  [[location(1), interpolate(flat)]] flat : f32,
+  [[location(2), interpolate(perspective, center)]] perspective_center : f32,
+  [[location(3), interpolate(perspective, centroid)]] perspective_centroid : f32,
+  [[location(4), interpolate(perspective, sample)]] perspective_sample : f32,
+  [[location(5), interpolate(linear, center)]] linear_center : f32,
+  [[location(6), interpolate(linear, centroid)]] linear_centroid : f32,
+  [[location(7), interpolate(linear, sample)]] linear_sample : f32) {
+}

diff --git a/test/shader_io/interpolate_input_parameters.wgsl.expected.hlsl b/test/shader_io/interpolate_input_parameters.wgsl.expected.hlsl
new file mode 100644
index 0000000..3cd1e7f
--- /dev/null
+++ b/test/shader_io/interpolate_input_parameters.wgsl.expected.hlsl

@@ -0,0 +1,10 @@
+SKIP: FAILED
+
+../../src/writer/hlsl/generator_impl.cc:2862 internal compiler error: TINT_UNIMPLEMENTED interpolate decoration
+********************************************************************
+*  The tint shader compiler has encountered an unexpected error.   *
+*                                                                  *
+*  Please help us fix this issue by submitting a bug report at     *
+*  crbug.com/tint with the source program that triggered the bug.  *
+********************************************************************
+

diff --git a/test/shader_io/interpolate_input_parameters.wgsl.expected.msl b/test/shader_io/interpolate_input_parameters.wgsl.expected.msl
new file mode 100644
index 0000000..41cb1fa
--- /dev/null
+++ b/test/shader_io/interpolate_input_parameters.wgsl.expected.msl

@@ -0,0 +1,10 @@
+SKIP: FAILED
+
+../../src/writer/msl/generator_impl.cc:1782 internal compiler error: TINT_UNIMPLEMENTED interpolate decoration
+********************************************************************
+*  The tint shader compiler has encountered an unexpected error.   *
+*                                                                  *
+*  Please help us fix this issue by submitting a bug report at     *
+*  crbug.com/tint with the source program that triggered the bug.  *
+********************************************************************
+

diff --git a/test/shader_io/interpolate_input_parameters.wgsl.expected.spvasm b/test/shader_io/interpolate_input_parameters.wgsl.expected.spvasm
new file mode 100644
index 0000000..ca6d27f
--- /dev/null
+++ b/test/shader_io/interpolate_input_parameters.wgsl.expected.spvasm

@@ -0,0 +1,24 @@
+SKIP: FAILED
+
+
+[[location(0), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol : f32;
+
+[[location(1), interpolate(flat), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_1 : f32;
+
+[[location(2), interpolate(perspective, center), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_2 : f32;
+
+[[location(3), interpolate(perspective, centroid), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_3 : f32;
+
+[[location(4), interpolate(perspective, sample), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_4 : f32;
+
+[[location(5), interpolate(linear, center), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_5 : f32;
+
+[[location(6), interpolate(linear, centroid), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_6 : f32;
+
+[[location(7), interpolate(linear, sample), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_7 : f32;
+
+[[stage(fragment)]]
+fn main() {
+}
+
+Failed to generate: unknown decoration

diff --git a/test/shader_io/interpolate_input_parameters.wgsl.expected.wgsl b/test/shader_io/interpolate_input_parameters.wgsl.expected.wgsl
new file mode 100644
index 0000000..3488ca7
--- /dev/null
+++ b/test/shader_io/interpolate_input_parameters.wgsl.expected.wgsl

@@ -0,0 +1,3 @@
+[[stage(fragment)]]
+fn main([[location(0)]] none : f32, [[location(1), interpolate(flat)]] flat : f32, [[location(2), interpolate(perspective, center)]] perspective_center : f32, [[location(3), interpolate(perspective, centroid)]] perspective_centroid : f32, [[location(4), interpolate(perspective, sample)]] perspective_sample : f32, [[location(5), interpolate(linear, center)]] linear_center : f32, [[location(6), interpolate(linear, centroid)]] linear_centroid : f32, [[location(7), interpolate(linear, sample)]] linear_sample : f32) {
+}

diff --git a/test/shader_io/interpolate_input_struct.wgsl b/test/shader_io/interpolate_input_struct.wgsl
new file mode 100644
index 0000000..0299250
--- /dev/null
+++ b/test/shader_io/interpolate_input_struct.wgsl

@@ -0,0 +1,14 @@
+struct In {
+  [[location(0)]] none : f32;
+  [[location(1), interpolate(flat)]] flat : f32;
+  [[location(2), interpolate(perspective, center)]] perspective_center : f32;
+  [[location(3), interpolate(perspective, centroid)]] perspective_centroid : f32;
+  [[location(4), interpolate(perspective, sample)]] perspective_sample : f32;
+  [[location(5), interpolate(linear, center)]] linear_center : f32;
+  [[location(6), interpolate(linear, centroid)]] linear_centroid : f32;
+  [[location(7), interpolate(linear, sample)]] linear_sample : f32;
+};
+
+[[stage(fragment)]]
+fn main(in : In) {
+}

diff --git a/test/shader_io/interpolate_input_struct.wgsl.expected.hlsl b/test/shader_io/interpolate_input_struct.wgsl.expected.hlsl
new file mode 100644
index 0000000..3cd1e7f
--- /dev/null
+++ b/test/shader_io/interpolate_input_struct.wgsl.expected.hlsl

@@ -0,0 +1,10 @@
+SKIP: FAILED
+
+../../src/writer/hlsl/generator_impl.cc:2862 internal compiler error: TINT_UNIMPLEMENTED interpolate decoration
+********************************************************************
+*  The tint shader compiler has encountered an unexpected error.   *
+*                                                                  *
+*  Please help us fix this issue by submitting a bug report at     *
+*  crbug.com/tint with the source program that triggered the bug.  *
+********************************************************************
+

diff --git a/test/shader_io/interpolate_input_struct.wgsl.expected.msl b/test/shader_io/interpolate_input_struct.wgsl.expected.msl
new file mode 100644
index 0000000..41cb1fa
--- /dev/null
+++ b/test/shader_io/interpolate_input_struct.wgsl.expected.msl

@@ -0,0 +1,10 @@
+SKIP: FAILED
+
+../../src/writer/msl/generator_impl.cc:1782 internal compiler error: TINT_UNIMPLEMENTED interpolate decoration
+********************************************************************
+*  The tint shader compiler has encountered an unexpected error.   *
+*                                                                  *
+*  Please help us fix this issue by submitting a bug report at     *
+*  crbug.com/tint with the source program that triggered the bug.  *
+********************************************************************
+

diff --git a/test/shader_io/interpolate_input_struct.wgsl.expected.spvasm b/test/shader_io/interpolate_input_struct.wgsl.expected.spvasm
new file mode 100644
index 0000000..619801a
--- /dev/null
+++ b/test/shader_io/interpolate_input_struct.wgsl.expected.spvasm

@@ -0,0 +1,35 @@
+SKIP: FAILED
+
+
+struct In {
+  none : f32;
+  flat : f32;
+  perspective_center : f32;
+  perspective_centroid : f32;
+  perspective_sample : f32;
+  linear_center : f32;
+  linear_centroid : f32;
+  linear_sample : f32;
+};
+
+[[location(0), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol : f32;
+
+[[location(1), interpolate(flat), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_1 : f32;
+
+[[location(2), interpolate(perspective, center), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_2 : f32;
+
+[[location(3), interpolate(perspective, centroid), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_3 : f32;
+
+[[location(4), interpolate(perspective, sample), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_4 : f32;
+
+[[location(5), interpolate(linear, center), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_5 : f32;
+
+[[location(6), interpolate(linear, centroid), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_6 : f32;
+
+[[location(7), interpolate(linear, sample), internal(disable_validation__ignore_storage_class)]] var<in> tint_symbol_7 : f32;
+
+[[stage(fragment)]]
+fn main() {
+}
+
+Failed to generate: unknown decoration

diff --git a/test/shader_io/interpolate_input_struct.wgsl.expected.wgsl b/test/shader_io/interpolate_input_struct.wgsl.expected.wgsl
new file mode 100644
index 0000000..b90c09b
--- /dev/null
+++ b/test/shader_io/interpolate_input_struct.wgsl.expected.wgsl

@@ -0,0 +1,22 @@
+struct In {
+  [[location(0)]]
+  none : f32;
+  [[location(1), interpolate(flat)]]
+  flat : f32;
+  [[location(2), interpolate(perspective, center)]]
+  perspective_center : f32;
+  [[location(3), interpolate(perspective, centroid)]]
+  perspective_centroid : f32;
+  [[location(4), interpolate(perspective, sample)]]
+  perspective_sample : f32;
+  [[location(5), interpolate(linear, center)]]
+  linear_center : f32;
+  [[location(6), interpolate(linear, centroid)]]
+  linear_centroid : f32;
+  [[location(7), interpolate(linear, sample)]]
+  linear_sample : f32;
+};
+
+[[stage(fragment)]]
+fn main(in : In) {
+}

diff --git a/test/shader_io/interpolate_return_struct.wgsl b/test/shader_io/interpolate_return_struct.wgsl
new file mode 100644
index 0000000..9d24e61
--- /dev/null
+++ b/test/shader_io/interpolate_return_struct.wgsl

@@ -0,0 +1,16 @@
+struct Out {
+  [[builtin(position)]] pos : vec4<f32>;
+  [[location(0)]] none : f32;
+  [[location(1), interpolate(flat)]] flat : f32;
+  [[location(2), interpolate(perspective, center)]] perspective_center : f32;
+  [[location(3), interpolate(perspective, centroid)]] perspective_centroid : f32;
+  [[location(4), interpolate(perspective, sample)]] perspective_sample : f32;
+  [[location(5), interpolate(linear, center)]] linear_center : f32;
+  [[location(6), interpolate(linear, centroid)]] linear_centroid : f32;
+  [[location(7), interpolate(linear, sample)]] linear_sample : f32;
+};
+
+[[stage(vertex)]]
+fn main() -> Out {
+  return Out();
+}

diff --git a/test/shader_io/interpolate_return_struct.wgsl.expected.hlsl b/test/shader_io/interpolate_return_struct.wgsl.expected.hlsl
new file mode 100644
index 0000000..3cd1e7f
--- /dev/null
+++ b/test/shader_io/interpolate_return_struct.wgsl.expected.hlsl

@@ -0,0 +1,10 @@
+SKIP: FAILED
+
+../../src/writer/hlsl/generator_impl.cc:2862 internal compiler error: TINT_UNIMPLEMENTED interpolate decoration
+********************************************************************
+*  The tint shader compiler has encountered an unexpected error.   *
+*                                                                  *
+*  Please help us fix this issue by submitting a bug report at     *
+*  crbug.com/tint with the source program that triggered the bug.  *
+********************************************************************
+

diff --git a/test/shader_io/interpolate_return_struct.wgsl.expected.msl b/test/shader_io/interpolate_return_struct.wgsl.expected.msl
new file mode 100644
index 0000000..41cb1fa
--- /dev/null
+++ b/test/shader_io/interpolate_return_struct.wgsl.expected.msl

@@ -0,0 +1,10 @@
+SKIP: FAILED
+
+../../src/writer/msl/generator_impl.cc:1782 internal compiler error: TINT_UNIMPLEMENTED interpolate decoration
+********************************************************************
+*  The tint shader compiler has encountered an unexpected error.   *
+*                                                                  *
+*  Please help us fix this issue by submitting a bug report at     *
+*  crbug.com/tint with the source program that triggered the bug.  *
+********************************************************************
+

diff --git a/test/shader_io/interpolate_return_struct.wgsl.expected.spvasm b/test/shader_io/interpolate_return_struct.wgsl.expected.spvasm
new file mode 100644
index 0000000..fb6b3c6
--- /dev/null
+++ b/test/shader_io/interpolate_return_struct.wgsl.expected.spvasm

@@ -0,0 +1,55 @@
+SKIP: FAILED
+
+
+[[builtin(pointsize), internal(disable_validation__ignore_storage_class)]] var<out> tint_pointsize : f32;
+
+struct Out {
+  pos : vec4<f32>;
+  none : f32;
+  flat : f32;
+  perspective_center : f32;
+  perspective_centroid : f32;
+  perspective_sample : f32;
+  linear_center : f32;
+  linear_centroid : f32;
+  linear_sample : f32;
+};
+
+[[builtin(position), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_1 : vec4<f32>;
+
+[[location(0), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_2 : f32;
+
+[[location(1), interpolate(flat), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_3 : f32;
+
+[[location(2), interpolate(perspective, center), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_4 : f32;
+
+[[location(3), interpolate(perspective, centroid), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_5 : f32;
+
+[[location(4), interpolate(perspective, sample), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_6 : f32;
+
+[[location(5), interpolate(linear, center), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_7 : f32;
+
+[[location(6), interpolate(linear, centroid), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_8 : f32;
+
+[[location(7), interpolate(linear, sample), internal(disable_validation__ignore_storage_class)]] var<out> tint_symbol_9 : f32;
+
+fn tint_symbol_10(tint_symbol : Out) {
+  tint_symbol_1 = tint_symbol.pos;
+  tint_symbol_2 = tint_symbol.none;
+  tint_symbol_3 = tint_symbol.flat;
+  tint_symbol_4 = tint_symbol.perspective_center;
+  tint_symbol_5 = tint_symbol.perspective_centroid;
+  tint_symbol_6 = tint_symbol.perspective_sample;
+  tint_symbol_7 = tint_symbol.linear_center;
+  tint_symbol_8 = tint_symbol.linear_centroid;
+  tint_symbol_9 = tint_symbol.linear_sample;
+}
+
+[[stage(vertex)]]
+fn main() {
+  tint_pointsize = 1.0;
+  tint_symbol_10(Out());
+  return;
+}
+
+Failed to generate: unknown decoration

diff --git a/test/shader_io/interpolate_return_struct.wgsl.expected.wgsl b/test/shader_io/interpolate_return_struct.wgsl.expected.wgsl
new file mode 100644
index 0000000..fad2030
--- /dev/null
+++ b/test/shader_io/interpolate_return_struct.wgsl.expected.wgsl

@@ -0,0 +1,25 @@
+struct Out {
+  [[builtin(position)]]
+  pos : vec4<f32>;
+  [[location(0)]]
+  none : f32;
+  [[location(1), interpolate(flat)]]
+  flat : f32;
+  [[location(2), interpolate(perspective, center)]]
+  perspective_center : f32;
+  [[location(3), interpolate(perspective, centroid)]]
+  perspective_centroid : f32;
+  [[location(4), interpolate(perspective, sample)]]
+  perspective_sample : f32;
+  [[location(5), interpolate(linear, center)]]
+  linear_center : f32;
+  [[location(6), interpolate(linear, centroid)]]
+  linear_centroid : f32;
+  [[location(7), interpolate(linear, sample)]]
+  linear_sample : f32;
+};
+
+[[stage(vertex)]]
+fn main() -> Out {
+  return Out();
+}