Merge pull request #641 from data-pup/instantiate_empty

Instantiate empty module

crates/fuzzing/Cargo.toml

@@ -19,3 +19,6 @@ log = "0.4.8"
 wasmparser = "0.42.1"
 wasmprinter = "0.2.0"
 wasmtime-jit = { path = "../jit" }
+
+[dev-dependencies]
+wat = "1.0"

crates/fuzzing/tests/regressions.rs

@@ -7,3 +7,9 @@
 
 #[allow(unused_imports)] // Until we actually have some regression tests...
 use wasmtime_fuzzing::*;
+
+#[test]
+fn instantiate_empty_module() {
+    let data = wat::parse_str(include_str!("./regressions/empty.wat")).unwrap();
+    oracles::instantiate(&data, wasmtime_jit::CompilationStrategy::Auto);
+}

crates/fuzzing/tests/regressions/empty.wat

@@ -0,0 +1 @@
+(module)

crates/jit/src/compiler.rs

@@ -156,33 +156,36 @@ impl Compiler {
 
         let dbg = if let Some(debug_data) = debug_data {
             let target_config = self.isa.frontend_config();
-            let triple = self.isa.triple().clone();
-            let mut funcs = Vec::new();
-            for (i, allocated) in allocated_functions.into_iter() {
-                let ptr = (*allocated) as *const u8;
-                let body_len = compilation.get(i).body.len();
-                funcs.push((ptr, body_len));
-            }
-            let module_vmctx_info = {
-                let ofs = VMOffsets::new(target_config.pointer_bytes(), &module);
-                let memory_offset =
-                    ofs.vmctx_vmmemory_definition_base(DefinedMemoryIndex::new(0)) as i64;
-                ModuleVmctxInfo {
-                    memory_offset,
-                    stack_slots,
+            let ofs = VMOffsets::new(target_config.pointer_bytes(), &module);
+            if ofs.num_defined_memories > 0 {
+                let mut funcs = Vec::new();
+                for (i, allocated) in allocated_functions.into_iter() {
+                    let ptr = (*allocated) as *const u8;
+                    let body_len = compilation.get(i).body.len();
+                    funcs.push((ptr, body_len));
                 }
-            };
-            let bytes = emit_debugsections_image(
-                triple,
-                &target_config,
-                &debug_data,
-                &module_vmctx_info,
-                &address_transform,
-                &value_ranges,
-                &funcs,
-            )
-            .map_err(|e| SetupError::DebugInfo(e))?;
-            Some(bytes)
+                let module_vmctx_info = {
+                    let memory_offset =
+                        ofs.vmctx_vmmemory_definition_base(DefinedMemoryIndex::new(0)) as i64;
+                    ModuleVmctxInfo {
+                        memory_offset,
+                        stack_slots,
+                    }
+                };
+                let bytes = emit_debugsections_image(
+                    self.isa.triple().clone(),
+                    &target_config,
+                    &debug_data,
+                    &module_vmctx_info,
+                    &address_transform,
+                    &value_ranges,
+                    &funcs,
+                )
+                .map_err(|e| SetupError::DebugInfo(e))?;
+                Some(bytes)
+            } else {
+                None
+            }
         } else {
             None
         };