Add verifier check to ensure each SIMD lane index is within bounds, fixes #1016

cranelift/codegen/src/verifier/mod.rs

@@ -1775,14 +1775,10 @@ impl<'a> Verifier<'a> {
     ) -> VerifierStepResult<()> {
         let inst_data = &self.func.dfg[inst];
 
-        // If this is some sort of a store instruction, get the memflags, else, just return.
-        let memflags = match *inst_data {
+        match *inst_data {
             ir::InstructionData::Store { flags, .. }
-            | ir::InstructionData::StoreComplex { flags, .. } => flags,
-            _ => return Ok(()),
-        };
-
-        if memflags.readonly() {
+            | ir::InstructionData::StoreComplex { flags, .. } => {
+                if flags.readonly() {
                     fatal!(
                         errors,
                         inst,
@@ -1792,6 +1788,36 @@ impl<'a> Verifier<'a> {
                     Ok(())
                 }
             }
+            ir::InstructionData::ExtractLane {
+                opcode: ir::instructions::Opcode::Extractlane,
+                lane,
+                arg,
+                ..
+            }
+            | ir::InstructionData::InsertLane {
+                opcode: ir::instructions::Opcode::Insertlane,
+                lane,
+                args: [arg, _],
+                ..
+            } => {
+                // We must be specific about the opcodes above because other instructions are using
+                // the ExtractLane/InsertLane formats.
+                let ty = self.func.dfg.value_type(arg);
+                if u16::from(lane) >= ty.lane_count() {
+                    fatal!(
+                        errors,
+                        inst,
+                        "The lane {} does not index into the type {}",
+                        lane,
+                        ty
+                    )
+                } else {
+                    Ok(())
+                }
+            }
+            _ => Ok(()),
+        }
+    }
 
     fn verify_safepoint_unused(
         &self,

cranelift/filetests/filetests/isa/x86/extractlane-binemit.clif

@@ -2,8 +2,8 @@ test binemit
 set enable_simd
 target x86_64 haswell
 
-; for extractlane, floats are legalized differently than integers and booleans; integers and booleans use x86_pextr
-; which is manually placed in the IR so that it can be binemit-tested
+; for extractlane, floats are legalized differently than integers and booleans; integers and
+; booleans use x86_pextr which is manually placed in the IR so that it can be binemit-tested
 
 function %test_extractlane_b8() {
 ebb0:

cranelift/filetests/filetests/verifier/simd-lane-index.clif

@@ -0,0 +1,41 @@
+test verifier
+set enable_simd
+target x86_64
+
+function %insertlane_i32x4() {
+ebb0:
+    v0 = vconst.i32x4 [0 0 0 0]
+    v1 = iconst.i32 42
+    v2 = insertlane v0, 4, v1 ; error: The lane 4 does not index into the type i32x4
+    return
+}
+
+function %insertlane_b16x8() {
+ebb0:
+    v0 = vconst.b16x8 [false false false false false false false false]
+    v1 = bconst.b16 true
+    v2 = insertlane v0, 8, v1 ; error: The lane 8 does not index into the type b16x8
+    return
+}
+
+function %insertlane_f64x2() {
+ebb0:
+    v0 = vconst.f64x2 0x00
+    v1 = f64const 0x0.1
+    v2 = insertlane v0, 2, v1 ; error: The lane 2 does not index into the type f64x2
+    return
+}
+
+function %extractlane_i32x4() {
+ebb0:
+    v0 = vconst.i32x4 [0 0 0 0]
+    v1 = extractlane v0, 4 ; error: The lane 4 does not index into the type i32x4
+    return
+}
+
+function %extractlane_b8x16() {
+ebb0:
+    v0 = vconst.b8x16 0x00
+    v1 = extractlane v0, 16 ; error: The lane 16 does not index into the type b8x16
+    return
+}