Replace From EvalException with standalone function and mark function cold

Reviewed By: ndmitchell

Differential Revision: D30887698

fbshipit-source-id: d6ea9bc75bb117d29e3d2220e06645b852b1a034

Author: stepancheg

starlark/src/eval/compiler/mod.rs

@@ -188,17 +188,17 @@ pub(crate) fn expr_throw<'v, T>(
     }
 }
 
-impl From<EvalException<'_>> for anyhow::Error {
-    fn from(x: EvalException) -> Self {
-        match x {
-            EvalException::Error(e) => e,
-            EvalException::Break => anyhow!("Break statement used outside of a loop"),
-            EvalException::Continue => anyhow!("Continue statement used outside of a loop"),
-            EvalException::Return(..) => {
-                anyhow!("Return statement used outside of a function call")
-            }
+#[cold]
+#[inline(never)]
+pub(crate) fn throw_eval_exception<T>(x: EvalException<'_>) -> anyhow::Result<T> {
+    Err(match x {
+        EvalException::Error(e) => e,
+        EvalException::Break => anyhow!("Break statement used outside of a loop"),
+        EvalException::Continue => anyhow!("Continue statement used outside of a loop"),
+        EvalException::Return(..) => {
+            anyhow!("Return statement used outside of a function call")
         }
-    }
+    })
 }
 
 pub(crate) struct Compiler<'a> {

starlark/src/eval/fragment/def.rs

@@ -26,7 +26,7 @@ use crate::{
             scope::{
                 Captured, CstAssignIdent, CstExpr, CstParameter, CstStmt, ScopeId, ScopeNames,
             },
-            Compiler, EvalException, StmtCompiled,
+            throw_eval_exception, Compiler, EvalException, StmtCompiled,
         },
         fragment::expr::{ExprCompiled, ExprCompiledValue},
         runtime::{
@@ -510,7 +510,7 @@ impl<'v, V: ValueLike<'v>> DefGen<V> {
 
         let ret = match res {
             Err(EvalException::Return(ret)) => ret,
-            Err(e) => return Err(e.into()),
+            Err(e) => return throw_eval_exception(e),
             Ok(_) => Value::new_none(),
         };
 

starlark/src/eval/mod.rs

@@ -29,7 +29,10 @@ use gazebo::{cast, prelude::*};
 use std::{intrinsics::unlikely, mem};
 
 use crate::{
-    eval::compiler::scope::{CompilerAstMap, ScopeData},
+    eval::compiler::{
+        scope::{CompilerAstMap, ScopeData},
+        throw_eval_exception,
+    },
     values::docs::DocString,
 };
 pub(crate) use compiler::scope::ScopeNames;
@@ -157,7 +160,7 @@ impl<'v, 'a> Evaluator<'v, 'a> {
         match res {
             Ok(_) => Ok(Value::new_none()),
             Err(EvalException::Return(x)) => Ok(x),
-            Err(e) => Err(e.into()),
+            Err(e) => throw_eval_exception(e),
         }
     }