[hlsl-out] fix fallthrough in switch statements

2026-04-22 03:02:01 -04:00 · 2022-05-14 16:46:08 +02:00
parent 7c7e96276a
commit 91ee407c87
7 changed files with 163 additions and 131 deletions
--- a/src/back/hlsl/writer.rs
+++ b/src/back/hlsl/writer.rs
@@ -1651,7 +1651,7 @@ impl<'a, W: fmt::Write> super::Writer<'a, W> {
                let indent_level_1 = level.next();
                let indent_level_2 = indent_level_1.next();

-                for case in cases {
+                for (i, case) in cases.iter().enumerate() {
                    match case.value {
                        crate::SwitchValue::Integer(value) => writeln!(
                            self.out,
@@ -1663,25 +1663,35 @@ impl<'a, W: fmt::Write> super::Writer<'a, W> {
                        }
                    }

+                    // FXC doesn't support fallthrough so we duplicate the body of the following case blocks
                    if case.fall_through {
-                        // Generate each fallthrough case statement in a new block. This is done to
-                        // prevent symbol collision of variables declared in these cases statements.
-                        writeln!(self.out, "{}/* fallthrough */", indent_level_2)?;
-                        writeln!(self.out, "{}{{", indent_level_2)?;
-                    }
-                    for sta in case.body.iter() {
-                        self.write_stmt(
-                            module,
-                            sta,
-                            func_ctx,
-                            back::Level(indent_level_2.0 + usize::from(case.fall_through)),
-                        )?;
-                    }
+                        let curr_len = i + 1;
+                        let end_case_idx = curr_len
+                            + cases
+                                .iter()
+                                .skip(curr_len)
+                                .position(|case| !case.fall_through)
+                                .unwrap();
+                        let indent_level_3 = indent_level_2.next();
+                        for case in &cases[i..=end_case_idx] {
+                            writeln!(self.out, "{}{{", indent_level_2)?;
+                            for sta in case.body.iter() {
+                                self.write_stmt(module, sta, func_ctx, indent_level_3)?;
+                            }
+                            writeln!(self.out, "{}}}", indent_level_2)?;
+                        }

-                    if case.fall_through {
-                        writeln!(self.out, "{}}}", indent_level_2)?;
-                    } else if case.body.last().map_or(true, |s| !s.is_terminator()) {
-                        writeln!(self.out, "{}break;", indent_level_2)?;
+                        let last_case = &cases[end_case_idx];
+                        if last_case.body.last().map_or(true, |s| !s.is_terminator()) {
+                            writeln!(self.out, "{}break;", indent_level_2)?;
+                        }
+                    } else {
+                        for sta in case.body.iter() {
+                            self.write_stmt(module, sta, func_ctx, indent_level_2)?;
+                        }
+                        if case.body.last().map_or(true, |s| !s.is_terminator()) {
+                            writeln!(self.out, "{}break;", indent_level_2)?;
+                        }
                    }

                    writeln!(self.out, "{}}}", indent_level_1)?;
--- a/tests/in/control-flow.wgsl
+++ b/tests/in/control-flow.wgsl
@@ -26,9 +26,12 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
            pos = 2;
            fallthrough;
        }
-        case 4: {}
-        default: {
+        case 4: {
            pos = 3;
+            fallthrough;
+        }
+        default: {
+            pos = 4;
        }
    }

--- a/tests/out/glsl/control-flow.main.Compute.glsl
+++ b/tests/out/glsl/control-flow.main.Compute.glsl
@@ -59,9 +59,10 @@ void main() {
            pos = 2;
            /* fallthrough */
        case 4:
-            break;
-        default:
            pos = 3;
+            /* fallthrough */
+        default:
+            pos = 4;
            break;
    }
    switch(0u) {
@@ -70,8 +71,8 @@ void main() {
        default:
            break;
    }
-    int _e10 = pos;
-    switch(_e10) {
+    int _e11 = pos;
+    switch(_e11) {
        case 1:
            pos = 0;
            break;
--- a/tests/out/hlsl/control-flow.hlsl
+++ b/tests/out/hlsl/control-flow.hlsl
@@ -60,16 +60,28 @@ void main(uint3 global_id : SV_DispatchThreadID)
            break;
        }
        case 3: {
-            /* fallthrough */
            {
                pos = 2;
            }
+            {
+                pos = 3;
+            }
+            {
+                pos = 4;
+            }
+            break;
        }
        case 4: {
+            {
+                pos = 3;
+            }
+            {
+                pos = 4;
+            }
            break;
        }
        default: {
-            pos = 3;
+            pos = 4;
            break;
        }
    }
@@ -81,8 +93,8 @@ void main(uint3 global_id : SV_DispatchThreadID)
            break;
        }
    }
-    int _expr10 = pos;
-    switch(_expr10) {
+    int _expr11 = pos;
+    switch(_expr11) {
        case 1: {
            pos = 0;
            break;
@@ -92,10 +104,12 @@ void main(uint3 global_id : SV_DispatchThreadID)
            return;
        }
        case 3: {
-            /* fallthrough */
            {
                pos = 2;
            }
+            {
+                return;
+            }
        }
        case 4: {
            return;
--- a/tests/out/msl/control-flow.msl
+++ b/tests/out/msl/control-flow.msl
@@ -72,10 +72,10 @@ kernel void main_(
            pos = 2;
        }
        case 4: {
-            break;
+            pos = 3;
        }
        default: {
-            pos = 3;
+            pos = 4;
            break;
        }
    }
@@ -87,8 +87,8 @@ kernel void main_(
            break;
        }
    }
-    int _e10 = pos;
-    switch(_e10) {
+    int _e11 = pos;
+    switch(_e11) {
        case 1: {
            pos = 0;
            break;
--- a/tests/out/spv/control-flow.spvasm
+++ b/tests/out/spv/control-flow.spvasm
@@ -1,136 +1,138 @@
 ; SPIR-V
 ; Version: 1.1
 ; Generator: rspirv
-; Bound: 68
+; Bound: 69
 OpCapability Shader
 %1 = OpExtInstImport "GLSL.std.450"
 OpMemoryModel Logical GLSL450
-OpEntryPoint GLCompute %43 "main" %40
-OpExecutionMode %43 LocalSize 1 1 1
-OpDecorate %40 BuiltIn GlobalInvocationId
+OpEntryPoint GLCompute %44 "main" %41
+OpExecutionMode %44 LocalSize 1 1 1
+OpDecorate %41 BuiltIn GlobalInvocationId
 %2 = OpTypeVoid
 %4 = OpTypeInt 32 1
 %3 = OpConstant  %4  1
 %5 = OpConstant  %4  0
 %6 = OpConstant  %4  2
 %7 = OpConstant  %4  3
-%9 = OpTypeInt 32 0
-%8 = OpConstant  %9  0
-%10 = OpTypeVector %9 3
-%14 = OpTypeFunction %2 %4
-%20 = OpTypeFunction %2
-%37 = OpTypePointer Function %4
-%38 = OpConstantNull  %4
-%41 = OpTypePointer Input %10
-%40 = OpVariable  %41  Input
-%45 = OpConstant  %9  2
-%46 = OpConstant  %9  1
-%47 = OpConstant  %9  72
-%48 = OpConstant  %9  264
-%13 = OpFunction  %2  None %14
-%12 = OpFunctionParameter  %4
-%11 = OpLabel
-OpBranch %15
-%15 = OpLabel
-OpSelectionMerge %16 None
-OpSwitch %12 %17
-%17 = OpLabel
+%8 = OpConstant  %4  4
+%10 = OpTypeInt 32 0
+%9 = OpConstant  %10  0
+%11 = OpTypeVector %10 3
+%15 = OpTypeFunction %2 %4
+%21 = OpTypeFunction %2
+%38 = OpTypePointer Function %4
+%39 = OpConstantNull  %4
+%42 = OpTypePointer Input %11
+%41 = OpVariable  %42  Input
+%46 = OpConstant  %10  2
+%47 = OpConstant  %10  1
+%48 = OpConstant  %10  72
+%49 = OpConstant  %10  264
+%14 = OpFunction  %2  None %15
+%13 = OpFunctionParameter  %4
+%12 = OpLabel
 OpBranch %16
 %16 = OpLabel
+OpSelectionMerge %17 None
+OpSwitch %13 %18
+%18 = OpLabel
+OpBranch %17
+%17 = OpLabel
 OpReturn
 OpFunctionEnd
-%19 = OpFunction  %2  None %20
-%18 = OpLabel
-OpBranch %21
-%21 = OpLabel
-OpSelectionMerge %22 None
-OpSwitch %5 %23 0 %24
-%24 = OpLabel
-OpBranch %22
-%23 = OpLabel
+%20 = OpFunction  %2  None %21
+%19 = OpLabel
 OpBranch %22
 %22 = OpLabel
+OpSelectionMerge %23 None
+OpSwitch %5 %24 0 %25
+%25 = OpLabel
+OpBranch %23
+%24 = OpLabel
+OpBranch %23
+%23 = OpLabel
 OpReturn
 OpFunctionEnd
-%27 = OpFunction  %2  None %14
-%26 = OpFunctionParameter  %4
-%25 = OpLabel
-OpBranch %28
-%28 = OpLabel
+%28 = OpFunction  %2  None %15
+%27 = OpFunctionParameter  %4
+%26 = OpLabel
 OpBranch %29
 %29 = OpLabel
-OpLoopMerge %30 %32 None
-OpBranch %31
-%31 = OpLabel
-OpSelectionMerge %33 None
-OpSwitch %26 %34 1 %35
-%35 = OpLabel
+OpBranch %30
+%30 = OpLabel
+OpLoopMerge %31 %33 None
 OpBranch %32
+%32 = OpLabel
+OpSelectionMerge %34 None
+OpSwitch %27 %35 1 %36
+%36 = OpLabel
+OpBranch %33
+%35 = OpLabel
+OpBranch %34
 %34 = OpLabel
 OpBranch %33
 %33 = OpLabel
-OpBranch %32
-%32 = OpLabel
-OpBranch %29
-%30 = OpLabel
+OpBranch %30
+%31 = OpLabel
 OpReturn
 OpFunctionEnd
-%43 = OpFunction  %2  None %20
-%39 = OpLabel
-%36 = OpVariable  %37  Function %38
-%42 = OpLoad  %10  %40
-OpBranch %44
-%44 = OpLabel
-OpControlBarrier %45 %46 %47
-OpControlBarrier %45 %45 %48
-OpSelectionMerge %49 None
-OpSwitch %3 %50
+%44 = OpFunction  %2  None %21
+%40 = OpLabel
+%37 = OpVariable  %38  Function %39
+%43 = OpLoad  %11  %41
+OpBranch %45
+%45 = OpLabel
+OpControlBarrier %46 %47 %48
+OpControlBarrier %46 %46 %49
+OpSelectionMerge %50 None
+OpSwitch %3 %51
+%51 = OpLabel
+OpStore %37 %3
+OpBranch %50
 %50 = OpLabel
-OpStore %36 %3
-OpBranch %49
-%49 = OpLabel
-%51 = OpLoad  %4  %36
-OpSelectionMerge %52 None
-OpSwitch %51 %53 1 %54 2 %55 3 %56 4 %57
-%54 = OpLabel
-OpStore %36 %5
-OpBranch %52
+%52 = OpLoad  %4  %37
+OpSelectionMerge %53 None
+OpSwitch %52 %54 1 %55 2 %56 3 %57 4 %58
 %55 = OpLabel
-OpStore %36 %3
-OpBranch %52
+OpStore %37 %5
+OpBranch %53
 %56 = OpLabel
-OpStore %36 %6
-OpBranch %57
+OpStore %37 %3
+OpBranch %53
 %57 = OpLabel
-OpBranch %52
-%53 = OpLabel
-OpStore %36 %7
-OpBranch %52
-%52 = OpLabel
-OpSelectionMerge %58 None
-OpSwitch %8 %59 0 %60
-%60 = OpLabel
-OpBranch %58
-%59 = OpLabel
+OpStore %37 %6
 OpBranch %58
 %58 = OpLabel
-%61 = OpLoad  %4  %36
-OpSelectionMerge %62 None
-OpSwitch %61 %63 1 %64 2 %65 3 %66 4 %67
-%64 = OpLabel
-OpStore %36 %5
-OpBranch %62
+OpStore %37 %7
+OpBranch %54
+%54 = OpLabel
+OpStore %37 %8
+OpBranch %53
+%53 = OpLabel
+OpSelectionMerge %59 None
+OpSwitch %9 %60 0 %61
+%61 = OpLabel
+OpBranch %59
+%60 = OpLabel
+OpBranch %59
+%59 = OpLabel
+%62 = OpLoad  %4  %37
+OpSelectionMerge %63 None
+OpSwitch %62 %64 1 %65 2 %66 3 %67 4 %68
 %65 = OpLabel
-OpStore %36 %3
-OpReturn
+OpStore %37 %5
+OpBranch %63
 %66 = OpLabel
-OpStore %36 %6
-OpBranch %67
+OpStore %37 %3
+OpReturn
 %67 = OpLabel
+OpStore %37 %6
+OpBranch %68
+%68 = OpLabel
+OpReturn
+%64 = OpLabel
+OpStore %37 %7
 OpReturn
 %63 = OpLabel
-OpStore %36 %7
-OpReturn
-%62 = OpLabel
 OpReturn
 OpFunctionEnd
--- a/tests/out/wgsl/control-flow.wgsl
+++ b/tests/out/wgsl/control-flow.wgsl
@@ -55,9 +55,11 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
            fallthrough;
        }
        case 4: {
+            pos = 3;
+            fallthrough;
        }
        default: {
-            pos = 3;
+            pos = 4;
        }
    }
    switch 0u {
@@ -66,8 +68,8 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
        default: {
        }
    }
-    let _e10 = pos;
-    switch _e10 {
+    let _e11 = pos;
+    switch _e11 {
        case 1: {
            pos = 0;
            break;