Validate GLSL flow control

In particular, it's an error to reach the end of a non-void function
without a return statement.

diff --git a/source/glsl/compiler.cpp b/source/glsl/compiler.cpp
index e2745e1b9ae41fe6756f7b86204bdd16c86dda10..7021c62d9a2949c9459e6fa183955829bf04f469 100644 (file)
--- a/source/glsl/compiler.cpp
+++ b/source/glsl/compiler.cpp
@@ -323,6 +323,7 @@ void Compiler::validate(Stage &stage)
        IdentifierValidator().apply(stage);
        ReferenceValidator().apply(stage);
        ExpressionValidator().apply(stage);
+       FlowControlValidator().apply(stage);
        StageInterfaceValidator().apply(stage);
 }
 

diff --git a/source/glsl/validate.cpp b/source/glsl/validate.cpp
index 62f997bb5c29ad6d8a507620c3d78745118fc80f..86afebedb1611871d5ecfa5e3b34fb2cbd59957a 100644 (file)
--- a/source/glsl/validate.cpp
+++ b/source/glsl/validate.cpp
@@ -699,6 +699,52 @@ void ExpressionValidator::visit(Return &ret)
 }
 
 
+FlowControlValidator::FlowControlValidator():
+       reachable(true)
+{ }
+
+void FlowControlValidator::visit(Block &block)
+{
+       for(NodeList<Statement>::const_iterator i=block.body.begin(); i!=block.body.end(); ++i)
+       {
+               if(!reachable)
+               {
+                       diagnose(**i, Diagnostic::WARN, "Unreachable code detected");
+                       break;
+               }
+               (*i)->visit(*this);
+       }
+}
+
+void FlowControlValidator::visit(FunctionDeclaration &func)
+{
+       func.body.visit(*this);
+
+       if(func.definition==&func && func.return_type_declaration)
+       {
+               const BasicTypeDeclaration *basic_ret = dynamic_cast<const BasicTypeDeclaration *>(func.return_type_declaration);
+               if(reachable && (!basic_ret || basic_ret->kind!=BasicTypeDeclaration::VOID))
+                       error(func, "Missing return statement at the end of a function not returning 'void'");
+       }
+       reachable = true;
+}
+
+void FlowControlValidator::visit(Conditional &cond)
+{
+       cond.body.visit(*this);
+       bool reachable_if_true = reachable;
+       reachable = true;
+       cond.else_body.visit(*this);
+       reachable |= reachable_if_true;
+}
+
+void FlowControlValidator::visit(Iteration &iter)
+{
+       iter.body.visit(*this);
+       reachable = true;
+}
+
+
 int StageInterfaceValidator::get_location(const Layout &layout)
 {
        for(vector<Layout::Qualifier>::const_iterator i=layout.qualifiers.begin(); i!=layout.qualifiers.end(); ++i)

diff --git a/source/glsl/validate.h b/source/glsl/validate.h
index fe52ff5aae1878aa0006c2dce8b4c60ca6b4b7af..d38849012e26fd4569919eaff31588fb144c3559 100644 (file)
--- a/source/glsl/validate.h
+++ b/source/glsl/validate.h
@@ -140,6 +140,27 @@ private:
        virtual void visit(Return &);
 };
 
+/** Verifies flow control constructs.  Functions returning non-void must have
+return statements.  Warnings are given about dead code. */
+class FlowControlValidator: private Validator
+{
+private:
+       bool reachable;
+
+public:
+       FlowControlValidator();
+
+       void apply(Stage &s) { stage = &s; s.content.visit(*this); }
+
+private:
+       virtual void visit(Block &);
+       virtual void visit(FunctionDeclaration &);
+       virtual void visit(Conditional &);
+       virtual void visit(Iteration &);
+       virtual void visit(Return &) { reachable = false; }
+       virtual void visit(Jump &) { reachable = false; }
+};
+
 /** Verifies that stage input and output interfaces are valid.  Linked
 variables must have matching types and locations and there must not be any
 overlap in locations. */

diff --git a/tests/glsl/dead_code.glsl b/tests/glsl/dead_code.glsl
index bdfd4503c521c04ebc706deb4eb31b741499855f..4c15cc1814a6b495b4f65caaaad1b113fd2c4a6b 100644 (file)
--- a/tests/glsl/dead_code.glsl
+++ b/tests/glsl/dead_code.glsl
@@ -9,6 +9,10 @@ void main()
        gl_Position = position;
 }
 
+/* Expected diagnostic:
+<test>:9: Unreachable code detected
+*/
+
 /* Expected output: vertex
 layout(location=0) uniform mat4 mvp;
 layout(location=0) in vec4 position;

diff --git a/tests/glsl/function_override.glsl b/tests/glsl/function_override.glsl
index c7e64d5233920f6a9b55b7a84b481e000016d88b..746ea8d39ea8852828bad3a383ecb0b07a4805b3 100644 (file)
--- a/tests/glsl/function_override.glsl
+++ b/tests/glsl/function_override.glsl
@@ -4,7 +4,7 @@ virtual float get_scale()
 {
        return 1.0;
 }
-int main()
+void main()
 {
        gl_Position = position*get_scale();
 }
@@ -15,7 +15,7 @@ float get_scale() override
 
 /* Expected output: vertex
 layout(location=0) in vec4 position;
-int main()
+void main()
 {
        gl_Position = position*2.0;
 }

diff --git a/tests/glsl/invalid_subscript.glsl b/tests/glsl/invalid_subscript.glsl
index 6826feffe74c0fecb15f6479fea546948a8dfce8..5f959ffb33391b105733c1ab3c2f62917065c28e 100644 (file)
--- a/tests/glsl/invalid_subscript.glsl
+++ b/tests/glsl/invalid_subscript.glsl
@@ -1,7 +1,7 @@
 #pragma MSP stage(vertex)
 layout(location=0) in vec4 position;
 layout(location=1) in float scale;
-int main()
+void main()
 {
        gl_Position = position[scale];
        gl_Position = scale[position];

diff --git a/tests/glsl/no_op_conversion.glsl b/tests/glsl/no_op_conversion.glsl
index 2e3ff57b35b91e9290976edec156376e974c72ad..f0f887e9d8ec11f13af4f82123326cebd0b8bc47 100644 (file)
--- a/tests/glsl/no_op_conversion.glsl
+++ b/tests/glsl/no_op_conversion.glsl
@@ -2,7 +2,7 @@ uniform mat4 mvp;
 
 #pragma MSP stage(vertex)
 layout(location=0) in vec4 position;
-int main()
+void main()
 {
        gl_Position = mat4(mvp)*vec4(position);
 }
@@ -10,7 +10,7 @@ int main()
 /* Expected output: vertex
 layout(location=0) uniform mat4 mvp;
 layout(location=0) in vec4 position;
-int main()
+void main()
 {
   gl_Position = mat4(mvp)*vec4(position);
 }

diff --git a/tests/glsl/unused_component_assignment.glsl b/tests/glsl/unused_component_assignment.glsl
index 0febd56170803d4a4d5969712c19b9431ea11faa..af880f5d102e28449ead0e72517ddbe42e151111 100644 (file)
--- a/tests/glsl/unused_component_assignment.glsl
+++ b/tests/glsl/unused_component_assignment.glsl
@@ -2,7 +2,7 @@ uniform mat4 mvp;
 
 #pragma MSP stage(vertex)
 layout(location=0) in vec4 position;
-int main()
+void main()
 {
        vec4 c0 = mvp[0]*position;
        vec4 c1 = mvp[1]*position;
@@ -19,7 +19,7 @@ int main()
 /* Expected output: vertex
 layout(location=0) uniform mat4 mvp;
 layout(location=0) in vec4 position;
-int main()
+void main()
 {
   vec4 c0 = mvp[0]*position;
   vec4 c1 = mvp[1]*position;