Revert "Remove currently unused Nop,Swap op"

youknowone · youknowone · commit 64f4d7f3a201 · 2025-01-25T23:14:30.000+09:00
This reverts commit 4beef2c.
diff --git a/compiler/codegen/src/compile.rs b/compiler/codegen/src/compile.rs
@@ -1880,7 +1880,7 @@ impl Compiler {
                 emit!(self, Instruction::Pop);
             } else {
                 // Show line coverage for default case (it doesn't create bytecode)
-                // emit!(self, Instruction::Nop);
+                emit!(self, Instruction::Nop);
             }
             self.compile_statements(&m.body)?;
         }
diff --git a/compiler/core/src/bytecode.rs b/compiler/core/src/bytecode.rs
@@ -370,6 +370,10 @@ pub type NameIdx = u32;
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[repr(u8)]
 pub enum Instruction {
+    /// No-op, don't do anything at all
+    ///
+    /// Equivalent to `NOP` in cpython bytecode
+    Nop,
     /// Importing by name
     ImportName {
         idx: Arg<NameIdx>,
@@ -428,6 +432,9 @@ pub enum Instruction {
         op: Arg<ComparisonOperator>,
     },
     Pop,
+    Swap {
+        index: Arg<u32>,
+    },
     Rotate2,
     Rotate3,
     Duplicate,
@@ -1177,6 +1184,7 @@ impl Instruction {
     ///
     pub fn stack_effect(&self, arg: OpArg, jump: bool) -> i32 {
         match self {
+            Nop => 0,
             ImportName { .. } | ImportNameless => -1,
             ImportStar => -1,
             ImportFrom { .. } => 1,
@@ -1197,6 +1205,7 @@ impl Instruction {
             | TestOperation { .. }
             | CompareOperation { .. } => -1,
             Pop => -1,
+            Swap { .. } => 0,
             Rotate2 | Rotate3 => 0,
             Duplicate => 1,
             Duplicate2 => 2,
@@ -1361,6 +1370,7 @@ impl Instruction {
             };
 
         match self {
+            Nop => w!(Nop),
             ImportName { idx } => w!(ImportName, name = idx),
             ImportNameless => w!(ImportNameless),
             ImportStar => w!(ImportStar),
@@ -1392,6 +1402,7 @@ impl Instruction {
             TestOperation { op } => w!(TestOperation, ?op),
             CompareOperation { op } => w!(CompareOperation, ?op),
             Pop => w!(Pop),
+            Swap { index } => w!(Swap, index),
             Rotate2 => w!(Rotate2),
             Rotate3 => w!(Rotate3),
             Duplicate => w!(Duplicate),
diff --git a/vm/src/frame.rs b/vm/src/frame.rs
@@ -517,6 +517,7 @@ impl ExecutingFrame<'_> {
         }
 
         match instruction {
+            bytecode::Instruction::Nop => Ok(None),
             bytecode::Instruction::LoadConst { idx } => {
                 self.push_value(self.code.constants[idx.get(arg) as usize].clone().into());
                 Ok(None)
@@ -672,6 +673,13 @@ impl ExecutingFrame<'_> {
                 self.pop_value();
                 Ok(None)
             }
+            bytecode::Instruction::Swap { index } => {
+                let len = self.state.stack.len();
+                self.state
+                    .stack
+                    .swap(len - 1, len - 1 - index.get(arg) as usize);
+                Ok(None)
+            }
             bytecode::Instruction::Duplicate => {
                 // Duplicate top of stack
                 let value = self.top_value();

Original file line number	Diff line number	Diff line change
`@@ -1880,7 +1880,7 @@ impl Compiler {`
`1880`	`1880`	`emit!(self, Instruction::Pop);`
`1881`	`1881`	`} else {`
`1882`	`1882`	`// Show line coverage for default case (it doesn't create bytecode)`
`1883`		`- // emit!(self, Instruction::Nop);`
	`1883`	`+ emit!(self, Instruction::Nop);`
`1884`	`1884`	`}`
`1885`	`1885`	`self.compile_statements(&m.body)?;`
`1886`	`1886`	`}`