From 2707915376ccd86834d5e767044b0434939d9cfd Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 9 Aug 2020 20:12:56 +0900
Subject: [PATCH] shaderir/glsl, shaderir/metal: Bug fix: Wrong local variables
 with multiple 'for' statements

---
 internal/shaderir/glsl/glsl.go   | 11 +---
 internal/shaderir/ir_test.go     | 95 ++++++++++++++++++++++++++++++++
 internal/shaderir/metal/metal.go | 11 +---
 3 files changed, 101 insertions(+), 16 deletions(-)

diff --git a/internal/shaderir/glsl/glsl.go b/internal/shaderir/glsl/glsl.go
index fd6724720..6f6a28460 100644
--- a/internal/shaderir/glsl/glsl.go
+++ b/internal/shaderir/glsl/glsl.go
@@ -330,13 +330,6 @@ func (c *compileContext) glslBlock(p *shaderir.Program, topBlock, block *shaderi
 		localVarIndex++
 	}
 
-	// For's variable is special and defiend in the for statement.
-	for _, s := range block.Stmts {
-		if s.Type == shaderir.For {
-			localVarIndex++
-		}
-	}
-
 	var glslExpr func(e *shaderir.Expr) string
 	glslExpr = func(e *shaderir.Expr) string {
 		switch e.Type {
@@ -447,7 +440,9 @@ func (c *compileContext) glslBlock(p *shaderir.Program, topBlock, block *shaderi
 			end := constantToNumberLiteral(ct, s.ForEnd)
 			t0, t1 := typeString(&t)
 			lines = append(lines, fmt.Sprintf("%sfor (%s %s%s = %s; %s %s %s; %s) {", idt, t0, v, t1, init, v, op, end, delta))
-			lines = append(lines, c.glslBlock(p, topBlock, s.Blocks[0], level+1, localVarIndex)...)
+			// For's variable is special and defiend in the for statement.
+			// Add 1 to the number of the local variables.
+			lines = append(lines, c.glslBlock(p, topBlock, s.Blocks[0], level+1, localVarIndex+1)...)
 			lines = append(lines, fmt.Sprintf("%s}", idt))
 		case shaderir.Continue:
 			lines = append(lines, idt+"continue;")
diff --git a/internal/shaderir/ir_test.go b/internal/shaderir/ir_test.go
index 84f2413cf..5fb9c56a0 100644
--- a/internal/shaderir/ir_test.go
+++ b/internal/shaderir/ir_test.go
@@ -757,6 +757,101 @@ void F0(float l0, float l1, thread float& l2) {
 		int l4 = 0;
 		l2 = l4;
 	}
+}`,
+		},
+		{
+			Name: "For3",
+			Program: Program{
+				Funcs: []Func{
+					{
+						Index: 0,
+						InParams: []Type{
+							{Main: Float},
+							{Main: Float},
+						},
+						OutParams: []Type{
+							{Main: Float},
+						},
+						Block: block(
+							nil,
+							forStmt(
+								3,
+								0,
+								100,
+								LessThanOp,
+								1,
+								block(
+									[]Type{
+										{Main: Int},
+									},
+									assignStmt(
+										localVariableExpr(2),
+										localVariableExpr(4),
+									),
+								),
+							),
+							forStmt(
+								3,
+								0,
+								100,
+								LessThanOp,
+								1,
+								block(
+									[]Type{
+										{Main: Int},
+									},
+									assignStmt(
+										localVariableExpr(2),
+										localVariableExpr(4),
+									),
+								),
+							),
+						),
+					},
+				},
+			},
+			GlslVS: `void F0(in float l0, in float l1, out float l2);
+
+void F0(in float l0, in float l1, out float l2) {
+	for (int l3 = 0; l3 < 100; l3++) {
+		int l4 = 0;
+		l2 = l4;
+	}
+	for (int l3 = 0; l3 < 100; l3++) {
+		int l4 = 0;
+		l2 = l4;
+	}
+}`,
+			GlslFS: glslPrelude + `
+void F0(in float l0, in float l1, out float l2);
+
+void F0(in float l0, in float l1, out float l2) {
+	for (int l3 = 0; l3 < 100; l3++) {
+		int l4 = 0;
+		l2 = l4;
+	}
+	for (int l3 = 0; l3 < 100; l3++) {
+		int l4 = 0;
+		l2 = l4;
+	}
+}`,
+			Metal: `#include <metal_stdlib>
+
+using namespace metal;
+
+constexpr sampler texture_sampler{filter::nearest};
+
+void F0(float l0, float l1, thread float& l2);
+
+void F0(float l0, float l1, thread float& l2) {
+	for (int l3 = 0; l3 < 100; l3++) {
+		int l4 = 0;
+		l2 = l4;
+	}
+	for (int l3 = 0; l3 < 100; l3++) {
+		int l4 = 0;
+		l2 = l4;
+	}
 }`,
 		},
 		{
diff --git a/internal/shaderir/metal/metal.go b/internal/shaderir/metal/metal.go
index 9cec7d0de..f9712dcd8 100644
--- a/internal/shaderir/metal/metal.go
+++ b/internal/shaderir/metal/metal.go
@@ -327,13 +327,6 @@ func (c *compileContext) metalBlock(p *shaderir.Program, topBlock, block *shader
 		localVarIndex++
 	}
 
-	// For's variable is special and defiend in the for statement.
-	for _, s := range block.Stmts {
-		if s.Type == shaderir.For {
-			localVarIndex++
-		}
-	}
-
 	var metalExpr func(e *shaderir.Expr) string
 	metalExpr = func(e *shaderir.Expr) string {
 		switch e.Type {
@@ -455,7 +448,9 @@ func (c *compileContext) metalBlock(p *shaderir.Program, topBlock, block *shader
 			end := constantToNumberLiteral(ct, s.ForEnd)
 			ts := typeString(&t, false, false)
 			lines = append(lines, fmt.Sprintf("%sfor (%s %s = %s; %s %s %s; %s) {", idt, ts, v, init, v, op, end, delta))
-			lines = append(lines, c.metalBlock(p, topBlock, s.Blocks[0], level+1, localVarIndex)...)
+			// For's variable is special and defiend in the for statement.
+			// Add 1 to the number of the local variables.
+			lines = append(lines, c.metalBlock(p, topBlock, s.Blocks[0], level+1, localVarIndex+1)...)
 			lines = append(lines, fmt.Sprintf("%s}", idt))
 		case shaderir.Continue:
 			lines = append(lines, idt+"continue;")