HLSL-IR: improve ICE error message

Helps with triaging.

Change-Id: I2a3a66921dc12c9f8b253d90446d9b3ba397a2e9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/210336
Reviewed-by: James Price <jrprice@google.com>
Auto-Submit: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/tint/lang/hlsl/writer/raise/shader_io.cc b/src/tint/lang/hlsl/writer/raise/shader_io.cc
index 0da0c57..3d3ec0a 100644
--- a/src/tint/lang/hlsl/writer/raise/shader_io.cc
+++ b/src/tint/lang/hlsl/writer/raise/shader_io.cc
@@ -109,7 +109,7 @@
             default:
                 break;
         }
-        TINT_UNREACHABLE();
+        TINT_UNREACHABLE() << "Unhandled builtin value: " << ToString(builtin);
     }
 
     struct MemberInfo {
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.dxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.dxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.dxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.dxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.fxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.fxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.fxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_1.wgsl.expected.ir.fxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.dxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.dxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.dxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.dxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.fxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.fxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.fxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_3.wgsl.expected.ir.fxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.dxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.dxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.dxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.dxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.fxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.fxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.fxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_4.wgsl.expected.ir.fxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.dxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.dxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.dxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.dxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.fxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.fxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.fxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_5.wgsl.expected.ir.fxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.dxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.dxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.dxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.dxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *
diff --git a/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.fxc.hlsl b/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.fxc.hlsl
index b0160ea..3c66ae3 100644
--- a/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.fxc.hlsl
+++ b/test/tint/extensions/clip_distances/clip_distances_size_8.wgsl.expected.ir.fxc.hlsl
@@ -1,6 +1,6 @@
 SKIP: FAILED
 
-..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:101 internal compiler error: TINT_UNREACHABLE 
+..\..\src\tint\lang\hlsl\writer\raise\shader_io.cc:112 internal compiler error: TINT_UNREACHABLE Unhandled builtin value: clip_distances
 ********************************************************************
 *  The tint shader compiler has encountered an unexpected error.   *
 *                                                                  *