Use 'static const' for spec constants in HLSL

If 'const' is used, the shader expects the variable to be backed by a constant buffer. 'static const' is probably preferred for a value that is initialized with a constant in the HLSL source code. FXC also emits a warning for 'const' variables with initializers, since 'static const' was probably intended.
rossy · Oct 21, 2017 · 1f16f0d · 1f16f0d
1 parent 129d8b5
commit 1f16f0d
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Showing 5 changed files with 18 additions and 17 deletions.
diff --git a/reference/shaders-hlsl/asm/comp/specialization-constant-workgroup.asm.comp b/reference/shaders-hlsl/asm/comp/specialization-constant-workgroup.asm.comp
@@ -1,6 +1,6 @@
-const uint _5 = 9u;
-const uint _6 = 4u;
-const uint3 gl_WorkGroupSize = uint3(_5, 20u, _6);
+static const uint _5 = 9u;
+static const uint _6 = 4u;
+static const uint3 gl_WorkGroupSize = uint3(_5, 20u, _6);
 
 RWByteAddressBuffer _4 : register(u0);
 

diff --git a/reference/shaders-hlsl/asm/comp/storage-buffer-basic.asm.comp b/reference/shaders-hlsl/asm/comp/storage-buffer-basic.asm.comp
@@ -1,6 +1,6 @@
-const uint _3 = 1u;
-const uint _4 = 3u;
-const uint3 gl_WorkGroupSize = uint3(_3, 2u, _4);
+static const uint _3 = 1u;
+static const uint _4 = 3u;
+static const uint3 gl_WorkGroupSize = uint3(_3, 2u, _4);
 
 RWByteAddressBuffer _8 : register(u0);
 RWByteAddressBuffer _9 : register(u1);

diff --git a/reference/shaders-hlsl/comp/builtins.comp b/reference/shaders-hlsl/comp/builtins.comp
@@ -1,4 +1,4 @@
-const uint3 gl_WorkGroupSize = uint3(8u, 4u, 2u);
+static const uint3 gl_WorkGroupSize = uint3(8u, 4u, 2u);
 
 static uint3 gl_WorkGroupID;
 static uint3 gl_LocalInvocationID;

diff --git a/reference/shaders-hlsl/frag/spec-constant.frag b/reference/shaders-hlsl/frag/spec-constant.frag
@@ -1,11 +1,11 @@
-const float a = 1.0f;
-const float b = 2.0f;
-const int c = 3;
-const int d = 4;
-const uint e = 5u;
-const uint f = 6u;
-const bool g = false;
-const bool h = true;
+static const float a = 1.0f;
+static const float b = 2.0f;
+static const int c = 3;
+static const int d = 4;
+static const uint e = 5u;
+static const uint f = 6u;
+static const bool g = false;
+static const bool h = true;
 
 struct Foo
 {

diff --git a/spirv_hlsl.cpp b/spirv_hlsl.cpp
@@ -644,14 +644,15 @@ void CompilerHLSL::emit_specialization_constants()
 			auto &type = get<SPIRType>(c.constant_type);
 			auto name = to_name(c.self);
 
-			statement("const ", variable_decl(type, name), " = ", constant_expression(c), ";");
+			statement("static const ", variable_decl(type, name), " = ", constant_expression(c), ";");
 			emitted = true;
 		}
 	}
 
 	if (workgroup_size_id)
 	{
-		statement("const uint3 gl_WorkGroupSize = ", constant_expression(get<SPIRConstant>(workgroup_size_id)), ";");
+		statement("static const uint3 gl_WorkGroupSize = ",
+		          constant_expression(get<SPIRConstant>(workgroup_size_id)), ";");
 		emitted = true;
 	}