fix(cranelift): fix get_function_name reference lookup (#5888)

* fix(cranelift): fix get_function_name reference lookup

Use sparse index for ir::ExternalName::user as UserExternalNameRef
are references to the user_named_funcs vector. We can then get
to the original FunctionIndex by a proper lookup to the
user_named_funcs.

Author: marxin

lib/compiler-cranelift/src/compiler.rs

@@ -173,6 +173,7 @@ impl CraneliftCompiler {
 
                 let mut code_buf: Vec<u8> = Vec::new();
                 let mut ctrl_plane = Default::default();
+                let func_name_map = context.func.params.user_named_funcs().clone();
                 let result = context
                     .compile(&*isa, &mut ctrl_plane)
                     .map_err(|error| CompileError::Codegen(error.inner.to_string()))?;
@@ -182,7 +183,7 @@ impl CraneliftCompiler {
                     .buffer
                     .relocs()
                     .into_iter()
-                    .map(|r| mach_reloc_to_reloc(module, r))
+                    .map(|r| mach_reloc_to_reloc(module, &func_name_map, r))
                     .collect::<Vec<_>>();
 
                 let traps = result
@@ -297,6 +298,7 @@ impl CraneliftCompiler {
 
                 let mut code_buf: Vec<u8> = Vec::new();
                 let mut ctrl_plane = Default::default();
+                let func_name_map = context.func.params.user_named_funcs().clone();
                 let result = context
                     .compile(&*isa, &mut ctrl_plane)
                     .map_err(|error| CompileError::Codegen(format!("{error:#?}")))?;
@@ -315,7 +317,7 @@ impl CraneliftCompiler {
                     .buffer
                     .relocs()
                     .iter()
-                    .map(|r| mach_reloc_to_reloc(module, r))
+                    .map(|r| mach_reloc_to_reloc(module, &func_name_map, r))
                     .collect::<Vec<_>>();
 
                 let traps = result
@@ -524,7 +526,11 @@ impl Compiler for CraneliftCompiler {
     }
 }
 
-fn mach_reloc_to_reloc(module: &ModuleInfo, reloc: &FinalizedMachReloc) -> Relocation {
+fn mach_reloc_to_reloc(
+    module: &ModuleInfo,
+    func_index_map: &cranelift_entity::PrimaryMap<ir::UserExternalNameRef, ir::UserExternalName>,
+    reloc: &FinalizedMachReloc,
+) -> Relocation {
     let FinalizedMachReloc {
         offset,
         kind,
@@ -538,10 +544,11 @@ fn mach_reloc_to_reloc(module: &ModuleInfo, reloc: &FinalizedMachReloc) -> Reloc
         }
     };
     let reloc_target: RelocationTarget = if let ExternalName::User(extname_ref) = name {
+        let func_index = func_index_map[*extname_ref].index;
         //debug_assert_eq!(namespace, 0);
         RelocationTarget::LocalFunc(
             module
-                .local_func_index(FunctionIndex::from_u32(extname_ref.as_u32()))
+                .local_func_index(FunctionIndex::from_u32(func_index))
                 .expect("The provided function should be local"),
         )
     } else if let ExternalName::LibCall(libcall) = name {

lib/compiler-cranelift/src/func_environ.rs

@@ -29,10 +29,10 @@ use wasmer_types::{
 
 /// Compute an `ir::ExternalName` for a given wasm function index.
 pub fn get_function_name(func: &mut Function, func_index: FunctionIndex) -> ir::ExternalName {
-    // Called as the function name offset is used for debugging purpose.
-    func.params
-        .ensure_user_func_name(UserExternalName::new(0, func_index.as_u32()));
-    ir::ExternalName::user(ir::UserExternalNameRef::from_u32(func_index.as_u32()))
+    ir::ExternalName::user(
+        func.params
+            .ensure_user_func_name(UserExternalName::new(0, func_index.as_u32())),
+    )
 }
 
 /// The type of the `current_elements` field.

tests/compilers/config.rs

@@ -70,7 +70,9 @@ impl Config {
         &self,
         #[allow(unused_variables)] canonicalize_nans: bool,
     ) -> Box<dyn CompilerConfig> {
-        let debug_dir = std::env::var("WASMER_DEBUG_DIR").ok().map(PathBuf::from);
+        let debug_dir = std::env::var("WASMER_COMPILER_DEBUG_DIR")
+            .ok()
+            .map(PathBuf::from);
 
         match &self.compiler {
             #[cfg(feature = "cranelift")]

tests/compilers/issues.rs

@@ -1,6 +1,9 @@
 //! This file is mainly to assure specific issues are working well
+use std::env;
+
 use anyhow::{Context, Result};
 use itertools::Itertools;
+use tempfile::TempDir;
 use wasmer::FunctionEnv;
 use wasmer::*;
 
@@ -587,3 +590,26 @@ fn huge_number_of_arguments_fn(
 
     Ok(())
 }
+
+#[compiler_test(issues)]
+fn compiler_debug_dir_test(mut config: crate::Config) {
+    let temp = TempDir::new().expect("temp folder creation failed");
+    unsafe {
+        env::set_var(
+            "WASMER_COMPILER_DEBUG_DIR",
+            temp.path()
+                .as_os_str()
+                .to_str()
+                .expect("path must be valid"),
+        );
+    }
+    let store = config.store();
+
+    let mut wat = include_str!("../wast/spec/fac.wast").to_string();
+    wat.truncate(
+        wat.find("(assert_return")
+            .expect("assert expected in the test"),
+    );
+
+    assert!(Module::new(&store, wat).is_ok());
+}