diff --git a/lib/clif-backend/src/code.rs b/lib/clif-backend/src/code.rs
index 24e36e58f..a7cb46517 100644
--- a/lib/clif-backend/src/code.rs
+++ b/lib/clif-backend/src/code.rs
@@ -6,8 +6,8 @@ use crate::{
     resolver::FuncResolverBuilder, signal::Caller, trampoline::Trampolines,
 };
 
-use cranelift_codegen::entity::{EntityRef, PrimaryMap};
-use cranelift_codegen::ir::{self, Ebb, Function, InstBuilder};
+use cranelift_codegen::entity::EntityRef;
+use cranelift_codegen::ir::{self, Ebb, Function, InstBuilder, ValueLabel};
 use cranelift_codegen::isa::CallConv;
 use cranelift_codegen::{cursor::FuncCursor, isa};
 use cranelift_frontend::{FunctionBuilder, Position, Variable};
@@ -71,6 +71,7 @@ impl ModuleCodeGenerator<CraneliftFunctionCodeGenerator, Caller, CodegenError>
     fn next_function(
         &mut self,
         module_info: Arc<RwLock<ModuleInfo>>,
+        loc: (u32, u32),
     ) -> Result<&mut CraneliftFunctionCodeGenerator, CodegenError> {
         // define_function_body(
 
@@ -101,8 +102,12 @@ impl ModuleCodeGenerator<CraneliftFunctionCodeGenerator, Caller, CodegenError>
                 target_config: self.isa.frontend_config().clone(),
                 clif_signatures: self.clif_signatures.clone(),
             },
+            start: loc.0,
+            end: loc.1,
         };
 
+        func_env.func.collect_debug_info();
+
         debug_assert_eq!(func_env.func.dfg.num_ebbs(), 0, "Function must be empty");
         debug_assert_eq!(func_env.func.dfg.num_insts(), 0, "Function must be empty");
 
@@ -112,8 +117,7 @@ impl ModuleCodeGenerator<CraneliftFunctionCodeGenerator, Caller, CodegenError>
             &mut func_env.position,
         );
 
-        // TODO srcloc
-        //builder.set_srcloc(cur_srcloc(&reader));
+        builder.set_srcloc(ir::SourceLoc::new(loc.0));
 
         let entry_block = builder.create_ebb();
         builder.append_ebb_params_for_function_params(entry_block);
@@ -141,37 +145,19 @@ impl ModuleCodeGenerator<CraneliftFunctionCodeGenerator, Caller, CodegenError>
     fn finalize(
         self,
         module_info: &ModuleInfo,
-    ) -> Result<((Caller, Option<wasmer_runtime_core::codegen::DebugMetadata>), Box<dyn CacheGen>), CodegenError> {
-
-        use wasm_debug::types::{CompiledFunctionData};
-        let mut debug_metadata = wasmer_runtime_core::codegen::DebugMetadata {
-            func_info: PrimaryMap::new(),
-            inst_info: PrimaryMap::new(),
-        };
-        let mut func_bodies: Map<LocalFuncIndex, ir::Function> = Map::new();
+    ) -> Result<
+        (
+            (Caller, Option<wasmer_runtime_core::codegen::DebugMetadata>),
+            Box<dyn CacheGen>,
+        ),
+        CodegenError,
+    > {
+        let mut func_bodies: Map<LocalFuncIndex, (ir::Function, (u32, u32))> = Map::new();
         for f in self.functions.into_iter() {
-            // TODO: review
-            // if container is stable, then first and last probably makes more sense here,
-            let min_srcloc = f.func.srclocs.iter().map(|x| x.1.bits()).min().unwrap_or_default();
-            let max_srcloc = f.func.srclocs.iter().map(|x| x.1.bits()).max().unwrap_or_default();
-            let entry = CompiledFunctionData {
-                instructions: vec![],
-                start: wasm_debug::types::SourceLoc::new(min_srcloc),
-                end: wasm_debug::types::SourceLoc::new(max_srcloc),
-                compiled_offset: 0,
-                compiled_size: 0,
-            };
-            debug_metadata.func_info.push(entry);
-            /*let mut map = std::collections::HashMap::new();
-            for (k, v) in f.func.srclocs {
-                map.
-            }
-            debug_metadata.inst_info.push(map);*/
-
-            func_bodies.push(f.func);
+            func_bodies.push((f.func, (f.start, f.end)));
         }
 
-        let (func_resolver_builder, handler_data) =
+        let (func_resolver_builder, debug_metadata, handler_data) =
             FuncResolverBuilder::new(&*self.isa, func_bodies, module_info)?;
 
         let trampolines = Arc::new(Trampolines::new(&*self.isa, module_info));
@@ -195,7 +181,10 @@ impl ModuleCodeGenerator<CraneliftFunctionCodeGenerator, Caller, CodegenError>
         ));
 
         Ok((
-            (Caller::new(handler_data, trampolines, func_resolver), Some(debug_metadata)),
+            (
+                Caller::new(handler_data, trampolines, func_resolver),
+                debug_metadata,
+            ),
             cache_gen,
         ))
     }
@@ -265,6 +254,8 @@ pub struct CraneliftFunctionCodeGenerator {
     next_local: usize,
     position: Position,
     func_env: FunctionEnvironment,
+    start: u32,
+    end: u32,
 }
 
 pub struct FunctionEnvironment {
@@ -467,7 +458,7 @@ impl FuncEnvironment for FunctionEnvironment {
                 let local_memory_bound = func.create_global_value(ir::GlobalValueData::Load {
                     base: local_memory_ptr,
                     offset: (vm::LocalMemory::offset_bound() as i32).into(),
-                    global_type: ptr_type,
+                    global_type: ir::types::I32,
                     readonly: false,
                 });
 
@@ -575,7 +566,7 @@ impl FuncEnvironment for FunctionEnvironment {
         let table_count = func.create_global_value(ir::GlobalValueData::Load {
             base: table_struct_ptr,
             offset: (vm::LocalTable::offset_count() as i32).into(),
-            global_type: ptr_type,
+            global_type: ir::types::I32,
             // The table length can change, so it can't be readonly.
             readonly: false,
         });
@@ -1092,13 +1083,14 @@ impl FunctionCodeGenerator<CodegenError> for CraneliftFunctionCodeGenerator {
         Ok(())
     }
 
-    fn feed_local(&mut self, ty: WpType, n: usize) -> Result<(), CodegenError> {
+    fn feed_local(&mut self, ty: WpType, n: usize, loc: u32) -> Result<(), CodegenError> {
         let mut next_local = self.next_local;
         let mut builder = FunctionBuilder::new(
             &mut self.func,
             &mut self.func_translator.func_ctx,
             &mut self.position,
         );
+        builder.set_srcloc(ir::SourceLoc::new(loc));
         cranelift_wasm::declare_locals(
             &mut builder,
             n as u32,
@@ -1114,7 +1106,7 @@ impl FunctionCodeGenerator<CodegenError> for CraneliftFunctionCodeGenerator {
         Ok(())
     }
 
-    fn feed_event(&mut self, event: Event, _module_info: &ModuleInfo) -> Result<(), CodegenError> {
+    fn feed_event(&mut self, event: Event, _module_info: &ModuleInfo, loc: u32) -> Result<(), CodegenError> {
         let op = match event {
             Event::Wasm(x) => x,
             Event::WasmOwned(ref x) => x,
@@ -1136,6 +1128,8 @@ impl FunctionCodeGenerator<CodegenError> for CraneliftFunctionCodeGenerator {
             &mut self.func_translator.func_ctx,
             &mut self.position,
         );
+        builder.func.collect_debug_info();
+        builder.set_srcloc(ir::SourceLoc::new(loc));
         let module_state = ModuleTranslationState::new();
         let func_state = &mut self.func_translator.state;
         translate_operator(
@@ -1145,6 +1139,7 @@ impl FunctionCodeGenerator<CodegenError> for CraneliftFunctionCodeGenerator {
             func_state,
             &mut self.func_env,
         )?;
+
         Ok(())
     }
 
@@ -1173,6 +1168,8 @@ impl FunctionCodeGenerator<CodegenError> for CraneliftFunctionCodeGenerator {
             }
         }
 
+        builder.finalize();
+
         // Discard any remaining values on the stack. Either we just returned them,
         // or the end of the function is unreachable.
         state.stack.clear();
@@ -1249,9 +1246,11 @@ fn declare_wasm_parameters(builder: &mut FunctionBuilder, entry_block: Ebb) -> u
             // This is a normal WebAssembly signature parameter, so create a local for it.
             let local = Variable::new(next_local);
             builder.declare_var(local, param_type.value_type);
+            let value_label = ValueLabel::from_u32(next_local as u32);
             next_local += 1;
 
             let param_value = builder.ebb_params(entry_block)[i];
+            builder.set_val_label(param_value, value_label);
             builder.def_var(local, param_value);
         }
         if param_type.purpose == ir::ArgumentPurpose::VMContext {
diff --git a/lib/clif-backend/src/lib.rs b/lib/clif-backend/src/lib.rs
index 06bffc791..5eccdcb2d 100644
--- a/lib/clif-backend/src/lib.rs
+++ b/lib/clif-backend/src/lib.rs
@@ -42,7 +42,7 @@ fn get_isa() -> Box<dyn isa::TargetIsa> {
         builder.set("opt_level", "speed_and_size").unwrap();
         builder.set("jump_tables_enabled", "false").unwrap();
 
-        if cfg!(not(test)) {
+        if cfg!(not(test)) && cfg!(not(debug)) {
             builder.set("enable_verifier", "false").unwrap();
         }
 
diff --git a/lib/clif-backend/src/module.rs b/lib/clif-backend/src/module.rs
index 11999ba02..1fb15b5f6 100644
--- a/lib/clif-backend/src/module.rs
+++ b/lib/clif-backend/src/module.rs
@@ -45,7 +45,6 @@ impl Module {
             runnable_module: Arc::new(Box::new(runnable_module)),
             cache_gen,
             info,
-            debug_info: None,
         })
     }
 }
diff --git a/lib/clif-backend/src/resolver.rs b/lib/clif-backend/src/resolver.rs
index efc038d58..e039af433 100644
--- a/lib/clif-backend/src/resolver.rs
+++ b/lib/clif-backend/src/resolver.rs
@@ -10,7 +10,9 @@ use crate::{
 };
 use byteorder::{ByteOrder, LittleEndian};
 use cranelift_codegen::{
+    ValueLabelsRanges,
     binemit::{Stackmap, StackmapSink},
+    entity::PrimaryMap,
     ir, isa, Context,
 };
 use rayon::prelude::*;
@@ -96,54 +98,159 @@ impl FuncResolverBuilder {
 
     pub fn new(
         isa: &dyn isa::TargetIsa,
-        function_bodies: Map<LocalFuncIndex, ir::Function>,
+        function_bodies: Map<LocalFuncIndex, (ir::Function, (u32, u32))>,
         info: &ModuleInfo,
-    ) -> CompileResult<(Self, HandlerData)> {
+    ) -> CompileResult<(
+        Self,
+        Option<wasmer_runtime_core::codegen::DebugMetadata>,
+        HandlerData,
+    )> {
         let num_func_bodies = function_bodies.len();
         let mut local_relocs = Map::with_capacity(num_func_bodies);
         let mut external_relocs = Map::with_capacity(num_func_bodies);
 
         let mut trap_sink = TrapSink::new();
 
-        let compiled_functions: Result<Vec<(Vec<u8>, (RelocSink, LocalTrapSink))>, CompileError> =
-            function_bodies
-                .into_vec()
-                .par_iter()
-                .map_init(
-                    || Context::new(),
-                    |ctx, func| {
-                        let mut code_buf = Vec::new();
-                        ctx.func = func.to_owned();
-                        let mut reloc_sink = RelocSink::new();
-                        let mut local_trap_sink = LocalTrapSink::new();
-                        let mut stackmap_sink = NoopStackmapSink {};
-                        ctx.compile_and_emit(
-                            isa,
-                            &mut code_buf,
-                            &mut reloc_sink,
-                            &mut local_trap_sink,
-                            &mut stackmap_sink,
-                        )
-                        .map_err(|e| CompileError::InternalError { msg: e.to_string() })?;
-                        ctx.clear();
-                        Ok((code_buf, (reloc_sink, local_trap_sink)))
-                    },
-                )
-                .collect();
+        let fb = function_bodies.iter().collect::<Vec<(_,_)>>();
+        rayon::ThreadPoolBuilder::new().num_threads(1).build_global().unwrap();
 
-        let compiled_functions = compiled_functions?;
+        let compiled_functions: Result<
+            Vec<(Vec<u8>,
+                (
+                    LocalFuncIndex,
+                    CompiledFunctionData,
+                    ValueLabelsRanges,
+                    Vec<Option<i32>>,
+                    RelocSink,
+                    LocalTrapSink,
+                ),
+            )>,
+            CompileError,
+            > =  fb
+            .par_iter()
+            .map_init(
+                || Context::new(),
+                |ctx, (lfi, (func, (start, end)))| {
+                    let mut code_buf = Vec::new();
+                    ctx.func = func.to_owned();
+                    let mut reloc_sink = RelocSink::new();
+                    let mut local_trap_sink = LocalTrapSink::new();
+                    let mut stackmap_sink = NoopStackmapSink {};
+
+                    //ctx.eliminate_unreachable_code(isa).unwrap();
+                    /*ctx.dce(isa).unwrap();
+                    ctx.shrink_instructions(isa).unwrap();
+                    ctx.redundant_reload_remover(isa).unwrap();
+                    ctx.preopt(isa).unwrap();
+                    ctx.legalize(isa).unwrap();
+                    ctx.postopt(isa).unwrap();*/
+                    ctx.verify(isa).unwrap();
+
+                    ctx.compile_and_emit(
+                        isa,
+                        &mut code_buf,
+                        &mut reloc_sink,
+                        &mut local_trap_sink,
+                        &mut stackmap_sink,
+                    )
+                    .map_err(|e| CompileError::InternalError { msg: e.to_string() })?;
+
+                    // begin debug stuff
+                    let func = &ctx.func;
+                    let encinfo = isa.encoding_info();
+                    let mut ebbs = func.layout.ebbs().collect::<Vec<_>>();
+                    ebbs.sort_by_key(|ebb| func.offsets[*ebb]);
+                    let instructions = /*func
+                        .layout
+                        .ebbs()*/
+                        ebbs.into_iter()
+                        .flat_map(|ebb| {
+                            func.inst_offsets(ebb, &encinfo)
+                                .map(|(offset, inst, length)| {
+                                    let srcloc = func.srclocs[inst];
+                                    let val = srcloc.bits();
+                                    wasm_debug::types::CompiledInstructionData {
+                                        // we write this data later
+                                        loc: wasm_debug::types::SourceLoc::new(val),//srcloc.bits()),
+                                        offset: offset as usize,
+                                        length: length as usize,
+                                    }
+                                })
+                        })
+                        .collect::<Vec<_>>();
+
+                    /*let mut unwind = vec![];
+                    ctx.emit_unwind_info(isa, &mut unwind);
+                    dbg!(unwind.len());*/
+
+                    let stack_slots = ctx.func.stack_slots.iter().map(|(_, ssd)| ssd.offset).collect::<Vec<Option<i32>>>();
+                    let labels_ranges = ctx.build_value_labels_ranges(isa).unwrap_or_default();
+                    if labels_ranges.len() == 24 || labels_ranges.len() == 25 {
+                        let mut vec = labels_ranges.iter().map(|(a,b)| (*a, b.clone())).collect::<Vec<_>>();
+                        vec.sort_by(|a, b| a.0.as_u32().cmp(&b.0.as_u32()));
+                        dbg!(labels_ranges.len(), &vec);
+                    }
+
+                    let entry = CompiledFunctionData {
+                        instructions,
+                        start: wasm_debug::types::SourceLoc::new(*start),
+                        end: wasm_debug::types::SourceLoc::new(*end),
+                        // this not being 0 breaks inst-level debugging
+                        compiled_offset: 0,
+                        compiled_size: code_buf.len(),
+                    };
+
+                    // end debug stuff
+
+                    ctx.clear();
+                    Ok((code_buf, (*lfi, entry, labels_ranges, stack_slots, reloc_sink, local_trap_sink)))
+                },
+            )
+            .collect();
+
+
+        use wasm_debug::types::CompiledFunctionData;
+        let mut debug_metadata = wasmer_runtime_core::codegen::DebugMetadata {
+            func_info: PrimaryMap::new(),
+            inst_info: PrimaryMap::new(),
+            pointers: vec![],
+            stack_slot_offsets: PrimaryMap::new(),
+        };
+
+        let mut compiled_functions = compiled_functions?;
+        compiled_functions.sort_by(|a, b| (a.1).0.cmp(&(b.1).0));
+        let compiled_functions = compiled_functions;
         let mut total_size = 0;
         // We separate into two iterators, one iterable and one into iterable
-        let (code_bufs, sinks): (Vec<Vec<u8>>, Vec<(RelocSink, LocalTrapSink)>) =
-            compiled_functions.into_iter().unzip();
-        for (code_buf, (reloc_sink, mut local_trap_sink)) in code_bufs.iter().zip(sinks.into_iter())
+        let (code_bufs, sinks): (
+            Vec<Vec<u8>>,
+            Vec<(
+                LocalFuncIndex,
+                CompiledFunctionData,
+                ValueLabelsRanges,
+                Vec<Option<i32>>,
+                RelocSink,
+                LocalTrapSink,
+            )>,
+        ) = compiled_functions.into_iter().unzip();
+        for (
+            code_buf,
+            (_, entry, vlr, stackslots, reloc_sink, mut local_trap_sink),
+        ) in code_bufs
+            .iter()
+            .zip(sinks.into_iter())
         {
+            let rounded_size = round_up(code_buf.len(), mem::size_of::<usize>());
+            debug_metadata.func_info.push(entry);
+            debug_metadata.inst_info.push(unsafe {std::mem::transmute(vlr)});
+            debug_metadata.stack_slot_offsets.push(stackslots);
+
             // Clear the local trap sink and consolidate all trap info
             // into a single location.
             trap_sink.drain_local(total_size, &mut local_trap_sink);
 
             // Round up each function's size to pointer alignment.
-            total_size += round_up(code_buf.len(), mem::size_of::<usize>());
+            total_size += rounded_size;
 
             local_relocs.push(reloc_sink.local_relocs.into_boxed_slice());
             external_relocs.push(reloc_sink.external_relocs.into_boxed_slice());
@@ -175,7 +282,12 @@ impl FuncResolverBuilder {
 
         let mut previous_end = 0;
         for compiled in code_bufs.iter() {
-            let new_end = previous_end + round_up(compiled.len(), mem::size_of::<usize>());
+            let length = round_up(compiled.len(), mem::size_of::<usize>());
+            debug_metadata.pointers.push((
+                (memory.as_ptr() as usize + previous_end) as *const u8,
+                length,
+            ));
+            let new_end = previous_end + length;
             unsafe {
                 memory.as_slice_mut()[previous_end..previous_end + compiled.len()]
                     .copy_from_slice(&compiled[..]);
@@ -197,7 +309,7 @@ impl FuncResolverBuilder {
 
         func_resolver_builder.relocate_locals();
 
-        Ok((func_resolver_builder, handler_data))
+        Ok((func_resolver_builder, Some(debug_metadata), handler_data))
     }
 
     fn relocate_locals(&mut self) {
diff --git a/lib/debug-writer/src/lib.rs b/lib/debug-writer/src/lib.rs
index 66a2b2513..655a5a6dc 100644
--- a/lib/debug-writer/src/lib.rs
+++ b/lib/debug-writer/src/lib.rs
@@ -1,13 +1,15 @@
 // TODO: add attribution to LLVM for data definitions and WasmTime for code structure
-use std::str::FromStr;
-use std::ptr;
 use std::ffi::c_void;
+use std::ptr;
+use std::str::FromStr;
 
-pub use wasm_debug::{read_debuginfo, DebugInfoData, WasmFileInfo};
 pub use wasm_debug::{emit_dwarf, ResolvedSymbol, SymbolResolver};
+pub use wasm_debug::{read_debuginfo, DebugInfoData, WasmFileInfo};
 
-use target_lexicon::{Triple, Architecture, Vendor, OperatingSystem, Environment, BinaryFormat};
-use gimli::write::{self, DwarfUnit, Sections, Address, RangeList, EndianVec, AttributeValue, Range};
+use gimli::write::{
+    self, Address, AttributeValue, DwarfUnit, EndianVec, Range, RangeList, Sections,
+};
+use target_lexicon::{Architecture, BinaryFormat, Environment, OperatingSystem, Triple, Vendor};
 
 use wasmer_runtime_core::{module::ModuleInfo, state::CodeVersion};
 
@@ -138,8 +140,8 @@ pub fn generate_dwarf(module_info: &ModuleInfo, debug_info_data: &DebugInfoData,
     //    `DW_AT_low_pc` and `DW_AT_high_pc` are good for continuous
     //    `DW_AT_low_pc` alone can work for a single address, but we can probably not
     //    worry about that for now.  These attribtues associate machine code with the DIE
-    // - 
-    
+    // -
+
     match platform {
         X86_64_GNU_LINUX => unimplemented!("in progress"),
         X86_64_OSX => unimplemented!("in progress"),
@@ -151,7 +153,12 @@ pub fn generate_dwarf(module_info: &ModuleInfo, debug_info_data: &DebugInfoData,
 */
 
 // converts existing dwarf into a usable form with metadata from the JIT
-fn reprocess_dwarf(module_info: &ModuleInfo, debug_info_data: &DebugInfoData, code_version: &CodeVersion, platform: Triple) -> Option<write::Dwarf> {
+fn reprocess_dwarf(
+    module_info: &ModuleInfo,
+    debug_info_data: &DebugInfoData,
+    code_version: &CodeVersion,
+    platform: Triple,
+) -> Option<write::Dwarf> {
     None
 }
 
diff --git a/lib/middleware-common/src/block_trace.rs b/lib/middleware-common/src/block_trace.rs
index f104ab086..1d539e44a 100644
--- a/lib/middleware-common/src/block_trace.rs
+++ b/lib/middleware-common/src/block_trace.rs
@@ -25,6 +25,7 @@ impl FunctionMiddleware for BlockTrace {
         op: Event<'a, 'b>,
         _module_info: &ModuleInfo,
         sink: &mut EventSink<'a, 'b>,
+        _loc: u32,
     ) -> Result<(), Self::Error> {
         match op {
             Event::Internal(InternalEvent::FunctionBegin(_)) => {
diff --git a/lib/middleware-common/src/call_trace.rs b/lib/middleware-common/src/call_trace.rs
index 5cb77534c..5f7f32032 100644
--- a/lib/middleware-common/src/call_trace.rs
+++ b/lib/middleware-common/src/call_trace.rs
@@ -26,6 +26,7 @@ impl FunctionMiddleware for CallTrace {
         op: Event<'a, 'b>,
         _module_info: &ModuleInfo,
         sink: &mut EventSink<'a, 'b>,
+        _loc: u32,
     ) -> Result<(), Self::Error> {
         let counter = self.counter.clone();
 
diff --git a/lib/middleware-common/src/metering.rs b/lib/middleware-common/src/metering.rs
index a7d10aece..a66fea509 100644
--- a/lib/middleware-common/src/metering.rs
+++ b/lib/middleware-common/src/metering.rs
@@ -44,6 +44,7 @@ impl FunctionMiddleware for Metering {
         op: Event<'a, 'b>,
         _module_info: &ModuleInfo,
         sink: &mut EventSink<'a, 'b>,
+        _loc: u32,
     ) -> Result<(), Self::Error> {
         match op {
             Event::Internal(InternalEvent::FunctionBegin(_)) => {
diff --git a/lib/runtime-core/src/codegen.rs b/lib/runtime-core/src/codegen.rs
index c72ca25df..835bc4501 100644
--- a/lib/runtime-core/src/codegen.rs
+++ b/lib/runtime-core/src/codegen.rs
@@ -112,9 +112,12 @@ pub trait ModuleCodeGenerator<FCG: FunctionCodeGenerator<E>, RM: RunnableModule,
     /// Checks the precondition for a module.
     fn check_precondition(&mut self, module_info: &ModuleInfo) -> Result<(), E>;
     /// Creates a new function and returns the function-scope code generator for it.
-    fn next_function(&mut self, module_info: Arc<RwLock<ModuleInfo>>) -> Result<&mut FCG, E>;
+    fn next_function(&mut self, module_info: Arc<RwLock<ModuleInfo>>, loc: (u32, u32)) -> Result<&mut FCG, E>;
     /// Finalizes this module.
-    fn finalize(self, module_info: &ModuleInfo) -> Result<((RM, Option<DebugMetadata>), Box<dyn CacheGen>), E>;
+    fn finalize(
+        self,
+        module_info: &ModuleInfo,
+    ) -> Result<((RM, Option<DebugMetadata>), Box<dyn CacheGen>), E>;
 
     /// Creates a module from cache.
     unsafe fn from_cache(cache: Artifact, _: Token) -> Result<ModuleInner, CacheError>;
@@ -127,6 +130,10 @@ pub struct DebugMetadata {
     pub func_info: PrimaryMap<FuncIndex, wasm_debug::types::CompiledFunctionData>,
     /// inst_info
     pub inst_info: PrimaryMap<FuncIndex, wasm_debug::types::ValueLabelsRangesInner>,
+    /// stack slot offsets!
+    pub stack_slot_offsets: PrimaryMap<FuncIndex, Vec<Option<i32>>>,
+    /// function pointers and their lengths
+    pub pointers: Vec<(*const u8, usize)>,
 }
 
 /// A streaming compiler which is designed to generated code for a module based on a stream
@@ -241,7 +248,6 @@ impl<
             validate_with_features(wasm, &compiler_config.features)?;
         }
 
-
         let mut mcg = match MCG::backend_id() {
             "llvm" => MCG::new_with_target(
                 compiler_config.triple.clone(),
@@ -252,13 +258,15 @@ impl<
         };
         let mut chain = (self.middleware_chain_generator)();
         let info = crate::parse::read_module(wasm, &mut mcg, &mut chain, &compiler_config)?;
-        let ((exec_context, debug_metadata), cache_gen) =
-            mcg.finalize(&info.read().unwrap())
-                .map_err(|x| CompileError::InternalError {
-                    msg: format!("{:?}", x),
-                })?;
+        let ((exec_context, debug_metadata), cache_gen) = mcg
+            .finalize(&info.read().unwrap())
+            .map_err(|x| CompileError::InternalError {
+                msg: format!("{:?}", x),
+            })?;
 
-        use target_lexicon::{Triple, Architecture, Vendor, OperatingSystem, Environment, BinaryFormat};
+        use target_lexicon::{
+            Architecture, BinaryFormat, Environment, OperatingSystem, Triple, Vendor,
+        };
         const X86_64_OSX: Triple = Triple {
             architecture: Architecture::X86_64,
             vendor: Vendor::Apple,
@@ -266,34 +274,37 @@ impl<
             environment: Environment::Unknown,
             binary_format: BinaryFormat::Macho,
         };
-        
+
         if compiler_config.generate_debug_info {
             let debug_metadata = debug_metadata.expect("debug metadata");
             let debug_info = wasm_debug::read_debuginfo(wasm);
-            let extra_info = wasm_debug::types::ModuleVmctxInfo {
-                memory_offset: 0,
-                stack_slot_offsets: cranelift_entity::PrimaryMap::new(),
-            };
+            let extra_info = wasm_debug::types::ModuleVmctxInfo::new(14 * 8, debug_metadata.stack_slot_offsets.values());
             // lazy type hack (TODO:)
-            let compiled_fn_map = unsafe { std::mem::transmute(debug_metadata.func_info) };
-            let range_map = unsafe { std::mem::transmute(debug_metadata.inst_info) };
-            let raw_func_slice = vec![];//exec_context.get_local_function_pointers_and_lengths().expect("raw func slice");
-            dbg!("DEBUG INFO GENERATED");
-            let debug_image = wasm_debug::emit_debugsections_image(X86_64_OSX,
-                                                 std::mem::size_of::<usize>() as u8,
-                                                 &debug_info,
-                                                 &extra_info,
-                                                 &compiled_fn_map,
-                                                 &range_map,
-                                                 &raw_func_slice).expect("make debug image");
+            let compiled_fn_map = wasm_debug::types::create_module_address_map(debug_metadata.func_info.values());
+            let range_map = wasm_debug::types::build_values_ranges(debug_metadata.inst_info.values());
+            let raw_func_slice = debug_metadata.pointers;
 
-            crate::jit_debug::register_new_jit_code_entry(&debug_image, crate::jit_debug::JITAction::JIT_REGISTER_FN);
-        } 
+            dbg!("DEBUG INFO GENERATED");
+            let debug_image = wasm_debug::emit_debugsections_image(
+                X86_64_OSX,
+                std::mem::size_of::<usize>() as u8,
+                &debug_info,
+                &extra_info,
+                &compiled_fn_map,
+                &range_map,
+                &raw_func_slice,
+            )
+            .expect("make debug image");
+
+            crate::jit_debug::register_new_jit_code_entry(
+                &debug_image,
+                crate::jit_debug::JITAction::JIT_REGISTER_FN,
+            );
+        }
         Ok(ModuleInner {
             cache_gen,
             runnable_module: Arc::new(Box::new(exec_context)),
             info: Arc::try_unwrap(info).unwrap().into_inner().unwrap(),
-            debug_info: None,
         })
     }
 
@@ -340,6 +351,7 @@ impl MiddlewareChain {
         fcg: Option<&mut FCG>,
         ev: Event,
         module_info: &ModuleInfo,
+        loc: u32,
     ) -> Result<(), String> {
         let mut sink = EventSink {
             buffer: SmallVec::new(),
@@ -348,12 +360,12 @@ impl MiddlewareChain {
         for m in &mut self.chain {
             let prev: SmallVec<[Event; 2]> = sink.buffer.drain().collect();
             for ev in prev {
-                m.feed_event(ev, module_info, &mut sink)?;
+                m.feed_event(ev, module_info, &mut sink, loc)?;
             }
         }
         if let Some(fcg) = fcg {
             for ev in sink.buffer {
-                fcg.feed_event(ev, module_info)
+                fcg.feed_event(ev, module_info, loc)
                     .map_err(|x| format!("{:?}", x))?;
             }
         }
@@ -372,6 +384,7 @@ pub trait FunctionMiddleware {
         op: Event<'a, 'b>,
         module_info: &ModuleInfo,
         sink: &mut EventSink<'a, 'b>,
+        loc: u32,
     ) -> Result<(), Self::Error>;
 }
 
@@ -381,6 +394,7 @@ pub(crate) trait GenericFunctionMiddleware {
         op: Event<'a, 'b>,
         module_info: &ModuleInfo,
         sink: &mut EventSink<'a, 'b>,
+        loc: u32,
     ) -> Result<(), String>;
 }
 
@@ -390,8 +404,9 @@ impl<E: Debug, T: FunctionMiddleware<Error = E>> GenericFunctionMiddleware for T
         op: Event<'a, 'b>,
         module_info: &ModuleInfo,
         sink: &mut EventSink<'a, 'b>,
+        loc: u32,
     ) -> Result<(), String> {
-        <Self as FunctionMiddleware>::feed_event(self, op, module_info, sink)
+        <Self as FunctionMiddleware>::feed_event(self, op, module_info, sink, loc)
             .map_err(|x| format!("{:?}", x))
     }
 }
@@ -405,13 +420,13 @@ pub trait FunctionCodeGenerator<E: Debug> {
     fn feed_param(&mut self, ty: WpType) -> Result<(), E>;
 
     /// Adds `n` locals to the function.
-    fn feed_local(&mut self, ty: WpType, n: usize) -> Result<(), E>;
+    fn feed_local(&mut self, ty: WpType, n: usize, loc: u32) -> Result<(), E>;
 
     /// Called before the first call to `feed_opcode`.
     fn begin_body(&mut self, module_info: &ModuleInfo) -> Result<(), E>;
 
     /// Called for each operator.
-    fn feed_event(&mut self, op: Event, module_info: &ModuleInfo) -> Result<(), E>;
+    fn feed_event(&mut self, op: Event, module_info: &ModuleInfo, loc: u32) -> Result<(), E>;
 
     /// Finalizes the function.
     fn finalize(&mut self) -> Result<(), E>;
diff --git a/lib/runtime-core/src/instance.rs b/lib/runtime-core/src/instance.rs
index d012ae8d6..bb8f29ad0 100644
--- a/lib/runtime-core/src/instance.rs
+++ b/lib/runtime-core/src/instance.rs
@@ -86,9 +86,14 @@ impl Instance {
                 None => vm::Ctx::new(backing, import_backing, &module),
             };
             vmctx.as_mut_ptr().write(real_ctx);
+            for (_, memory) in backing.vm_memories.iter_mut() {
+                let mem: &mut vm::LocalMemory = &mut **memory;
+                mem.vmctx = dbg!(vmctx.as_mut_ptr());
+            }
         };
         Box::leak(vmctx);
 
+
         let instance = Instance {
             module,
             inner,
diff --git a/lib/runtime-core/src/jit_debug.rs b/lib/runtime-core/src/jit_debug.rs
index 8a56fcd7f..f00d07bf6 100644
--- a/lib/runtime-core/src/jit_debug.rs
+++ b/lib/runtime-core/src/jit_debug.rs
@@ -8,15 +8,25 @@ use std::ptr;
 //
 // see also https://sourceware.org/gdb/current/onlinedocs/gdb.html#JIT-Interface
 
+#[no_mangle]
 #[inline(never)]
-pub extern "C" fn __jit_debug_register_code() {
-    
+extern "C" fn __jit_debug_register_code() {
+    // implementation of this function copied from wasmtime (TODO: link and attribution)
+    // prevent optimization of this function
+    let x = 3;
+    unsafe {
+        std::ptr::read_volatile(&x);
+    }
 }
 
 #[allow(non_camel_case_types)]
 #[derive(Debug)]
 #[repr(u32)]
-pub enum JITAction { JIT_NOACTION = 0, JIT_REGISTER_FN = 1, JIT_UNREGISTER_FN = 2 }
+pub enum JITAction {
+    JIT_NOACTION = 0,
+    JIT_REGISTER_FN = 1,
+    JIT_UNREGISTER_FN = 2,
+}
 
 #[no_mangle]
 #[repr(C)]
@@ -76,9 +86,15 @@ unsafe fn push_front(jce: *mut JITCodeEntry) {
 
 // deleted static (added and deleted by Mark): TODO:
 pub fn register_new_jit_code_entry(bytes: &[u8], action: JITAction) -> *mut JITCodeEntry {
+    let owned_bytes = bytes.iter().cloned().collect::<Vec<u8>>();
+    let ptr = owned_bytes.as_ptr();
+    let len = owned_bytes.len();
+
+    std::mem::forget(bytes);
+
     let entry: *mut JITCodeEntry = Box::into_raw(Box::new(JITCodeEntry {
-        symfile_addr: bytes.as_ptr(),
-        symfile_size: bytes.len() as _,
+        symfile_addr: ptr,
+        symfile_size: len as _,
         ..JITCodeEntry::default()
     }));
 
@@ -86,6 +102,9 @@ pub fn register_new_jit_code_entry(bytes: &[u8], action: JITAction) -> *mut JITC
         push_front(entry);
         __jit_debug_descriptor.relevant_entry = entry;
         __jit_debug_descriptor.action_flag = action as u32;
+        __jit_debug_register_code();
+        __jit_debug_descriptor.relevant_entry = ptr::null_mut();
+        __jit_debug_descriptor.action_flag = JITAction::JIT_NOACTION as _;
     }
 
     entry
diff --git a/lib/runtime-core/src/lib.rs b/lib/runtime-core/src/lib.rs
index 46f46f34a..8f808be74 100644
--- a/lib/runtime-core/src/lib.rs
+++ b/lib/runtime-core/src/lib.rs
@@ -66,10 +66,10 @@ pub mod vmcalls;
 pub use trampoline_x64 as trampoline;
 #[cfg(unix)]
 pub mod fault;
+pub mod jit_debug;
 pub mod state;
 #[cfg(feature = "managed")]
 pub mod tiering;
-pub mod jit_debug;
 
 use self::error::CompileResult;
 #[doc(inline)]
diff --git a/lib/runtime-core/src/memory/mod.rs b/lib/runtime-core/src/memory/mod.rs
index 75a02e227..95458eda4 100644
--- a/lib/runtime-core/src/memory/mod.rs
+++ b/lib/runtime-core/src/memory/mod.rs
@@ -227,6 +227,7 @@ impl UnsharedMemory {
             base: std::ptr::null_mut(),
             bound: 0,
             memory: std::ptr::null_mut(),
+            vmctx: std::ptr::null_mut(),
         };
 
         let storage = match desc.memory_type() {
@@ -314,6 +315,7 @@ impl SharedMemory {
             base: std::ptr::null_mut(),
             bound: 0,
             memory: std::ptr::null_mut(),
+            vmctx: std::ptr::null_mut(),
         };
 
         let memory = StaticMemory::new(desc, &mut local)?;
diff --git a/lib/runtime-core/src/module.rs b/lib/runtime-core/src/module.rs
index cfe9aaa3c..4b04a6d6b 100644
--- a/lib/runtime-core/src/module.rs
+++ b/lib/runtime-core/src/module.rs
@@ -20,18 +20,12 @@ use indexmap::IndexMap;
 use std::collections::HashMap;
 use std::sync::Arc;
 
-#[doc(hidden)]
-pub struct DebugInfo {
-    
-}
-
 /// This is used to instantiate a new WebAssembly module.
 #[doc(hidden)]
 pub struct ModuleInner {
     pub runnable_module: Arc<Box<dyn RunnableModule>>,
     pub cache_gen: Box<dyn CacheGen>,
     pub info: ModuleInfo,
-    pub debug_info: Option<DebugInfo>,
 }
 
 /// Container for module data including memories, globals, tables, imports, and exports.
@@ -83,6 +77,18 @@ pub struct ModuleInfo {
 
     /// Custom sections.
     pub custom_sections: HashMap<String, Vec<u8>>,
+
+    /// Debug info for funcs
+    pub func_debug_info: Map<FuncIndex, FuncDebugInfo>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
+/// info about functions for debugging
+pub struct FuncDebugInfo {
+    /// byte offset from start of code section where the function starts at
+    pub start: u32,
+    /// byte offset from start of code section where the function starts at
+    pub end: u32,
 }
 
 impl ModuleInfo {
diff --git a/lib/runtime-core/src/parse.rs b/lib/runtime-core/src/parse.rs
index ad91afb77..b6a7ff6d5 100644
--- a/lib/runtime-core/src/parse.rs
+++ b/lib/runtime-core/src/parse.rs
@@ -6,8 +6,8 @@ use crate::{
     backend::{CompilerConfig, RunnableModule},
     error::CompileError,
     module::{
-        DataInitializer, ExportIndex, ImportName, ModuleInfo, StringTable, StringTableBuilder,
-        TableInitializer,
+        DataInitializer, ExportIndex, FuncDebugInfo, ImportName, ModuleInfo, StringTable,
+        StringTableBuilder, TableInitializer,
     },
     structures::{Map, TypedIndex},
     types::{
@@ -90,6 +90,8 @@ pub fn read_module<
         em_symbol_map: compiler_config.symbol_map.clone(),
 
         custom_sections: HashMap::new(),
+
+        func_debug_info: Map::new(),
     }));
 
     let mut parser = wasmparser::ValidatingParser::new(
@@ -206,91 +208,113 @@ pub fn read_module<
             ParserState::StartSectionEntry(start_index) => {
                 info.write().unwrap().start_func = Some(FuncIndex::new(start_index as usize));
             }
-            ParserState::BeginFunctionBody { .. } => {
+            ParserState::BeginFunctionBody { range } => {
                 let id = func_count;
                 if !mcg_info_fed {
                     mcg_info_fed = true;
-                    info.write().unwrap().namespace_table =
-                        namespace_builder.take().unwrap().finish();
-                    info.write().unwrap().name_table = name_builder.take().unwrap().finish();
-                    mcg.feed_signatures(info.read().unwrap().signatures.clone())
+                    {
+                        let mut info_write = info.write().unwrap();
+                        info_write.namespace_table = namespace_builder.take().unwrap().finish();
+                        info_write.name_table = name_builder.take().unwrap().finish();
+                    }
+                    let info_read = info.read().unwrap();
+                    mcg.feed_signatures(info_read.signatures.clone())
                         .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
-                    mcg.feed_function_signatures(info.read().unwrap().func_assoc.clone())
+                    mcg.feed_function_signatures(info_read.func_assoc.clone())
                         .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
-                    mcg.check_precondition(&info.read().unwrap())
+                    mcg.check_precondition(&info_read)
                         .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
                 }
 
+
                 let fcg = mcg
-                    .next_function(Arc::clone(&info))
+                    .next_function(Arc::clone(&info), (range.start as u32, range.end as u32))
                     .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
 
-                let info_read = info.read().unwrap();
-                let sig = info_read
-                    .signatures
-                    .get(
-                        *info
-                            .read()
-                            .unwrap()
-                            .func_assoc
-                            .get(FuncIndex::new(
-                                id as usize + info.read().unwrap().imported_functions.len(),
-                            ))
-                            .unwrap(),
-                    )
-                    .unwrap();
-                for ret in sig.returns() {
-                    fcg.feed_return(type_to_wp_type(*ret))
-                        .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
-                }
-                for param in sig.params() {
-                    fcg.feed_param(type_to_wp_type(*param))
-                        .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
-                }
-
-                let mut body_begun = false;
-
-                loop {
-                    let state = parser.read();
-                    match state {
-                        ParserState::Error(err) => return Err(LoadError::Parse(*err)),
-                        ParserState::FunctionBodyLocals { ref locals } => {
-                            for &(count, ty) in locals.iter() {
-                                fcg.feed_local(ty, count as usize)
-                                    .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
-                            }
-                        }
-                        ParserState::CodeOperator(op) => {
-                            if !body_begun {
-                                body_begun = true;
-                                fcg.begin_body(&info.read().unwrap())
-                                    .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
-                                middlewares
-                                    .run(
-                                        Some(fcg),
-                                        Event::Internal(InternalEvent::FunctionBegin(id as u32)),
-                                        &info.read().unwrap(),
-                                    )
-                                    .map_err(LoadError::Codegen)?;
-                            }
-                            middlewares
-                                .run(Some(fcg), Event::Wasm(op), &info.read().unwrap())
-                                .map_err(LoadError::Codegen)?;
-                        }
-                        ParserState::EndFunctionBody => break,
-                        _ => unreachable!(),
+                {
+                    let info_read = info.read().unwrap();
+                    let sig = info_read
+                        .signatures
+                        .get(
+                            *info
+                                .read()
+                                .unwrap()
+                                .func_assoc
+                                .get(FuncIndex::new(
+                                    id as usize + info_read.imported_functions.len(),
+                                ))
+                                .unwrap(),
+                        )
+                        .unwrap();
+                    for ret in sig.returns() {
+                        fcg.feed_return(type_to_wp_type(*ret))
+                            .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
+                    }
+                    for param in sig.params() {
+                        fcg.feed_param(type_to_wp_type(*param))
+                            .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
                     }
                 }
-                middlewares
-                    .run(
-                        Some(fcg),
-                        Event::Internal(InternalEvent::FunctionEnd),
-                        &info.read().unwrap(),
-                    )
-                    .map_err(LoadError::Codegen)?;
+
+                let mut operator_parser = parser.create_binary_reader();
+
+                // read locals in function body
+                {
+                    let local_count = operator_parser.read_local_count().unwrap();
+                    let mut total = 0;
+                    for _ in 0..local_count {
+                        let cur_pos = range.start as u32 + operator_parser.current_position() as u32;
+                        let (count, ty) = operator_parser
+                            .read_local_decl(&mut total)
+                            .expect("Expected local");
+                        fcg.feed_local(ty, count as usize, cur_pos)
+                            .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
+                    }
+                }
+
+                // read instruction locations into vector for debug purposes
+                {
+                    let info_read = info.read().unwrap();
+                    let mut cur_pos = range.start as u32 + operator_parser.current_position() as u32;
+                    fcg.begin_body(&info_read)
+                        .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
+                    middlewares
+                        .run(
+                            Some(fcg),
+                            Event::Internal(InternalEvent::FunctionBegin(id as u32)),
+                            &info_read,
+                            cur_pos,
+                        )
+                        .map_err(LoadError::Codegen)?;
+
+                    while let Ok(op) = operator_parser.read_operator() {
+                        middlewares
+                            .run(Some(fcg), Event::WasmOwned(op), &info_read, cur_pos)
+                            .map_err(LoadError::Codegen)?;
+                        cur_pos = range.start as u32 + operator_parser.current_position() as u32;
+                    }
+
+                    cur_pos = range.start as u32 + operator_parser.current_position() as u32;
+                    middlewares
+                        .run(
+                            Some(fcg),
+                            Event::Internal(InternalEvent::FunctionEnd),
+                            &info_read,
+                            cur_pos,
+                        )
+                        .map_err(LoadError::Codegen)?;
+                }
+
                 fcg.finalize()
                     .map_err(|x| LoadError::Codegen(format!("{:?}", x)))?;
                 func_count = func_count.wrapping_add(1);
+
+                // debug info
+                let debug_entry = FuncDebugInfo {
+                    start: range.start as u32,
+                    end: range.end as u32,
+                };
+                info.write().unwrap().func_debug_info.push(debug_entry);
             }
             ParserState::BeginActiveElementSectionEntry(table_index) => {
                 let table_index = TableIndex::new(table_index as usize);
diff --git a/lib/runtime-core/src/vm.rs b/lib/runtime-core/src/vm.rs
index 2a39bdec1..ceb7e3114 100644
--- a/lib/runtime-core/src/vm.rs
+++ b/lib/runtime-core/src/vm.rs
@@ -8,7 +8,7 @@ use crate::{
     module::{ModuleInfo, ModuleInner},
     sig_registry::SigRegistry,
     structures::TypedIndex,
-    types::{LocalOrImport, MemoryIndex, TableIndex, Value},
+    types::{LocalOrImport, MemoryIndex, TableIndex, Value, LocalMemoryIndex},
     vmcalls,
 };
 use std::{
@@ -134,6 +134,9 @@ pub struct InternalCtx {
 
     /// Interrupt signal mem.
     pub interrupt_signal_mem: *mut u8,
+
+    /// hmm
+    pub first_mem: *mut LocalMemory,
 }
 
 static INTERNAL_FIELDS: AtomicUsize = AtomicUsize::new(0);
@@ -283,6 +286,7 @@ impl Ctx {
                 };
                 ((*mem).base, (*mem).bound)
             };
+        dbg!(mem_bound);
         Self {
             internal: InternalCtx {
                 memories: local_backing.vm_memories.as_mut_ptr(),
@@ -306,6 +310,7 @@ impl Ctx {
                 internals: &mut local_backing.internals.0,
 
                 interrupt_signal_mem: get_interrupt_signal_mem(),
+                first_mem: local_backing.vm_memories[LocalMemoryIndex::new(0)],
             },
             local_functions: local_backing.local_functions.as_ptr(),
 
@@ -336,6 +341,8 @@ impl Ctx {
                 };
                 ((*mem).base, (*mem).bound)
             };
+
+        dbg!(mem_bound);
         Self {
             internal: InternalCtx {
                 memories: local_backing.vm_memories.as_mut_ptr(),
@@ -359,6 +366,8 @@ impl Ctx {
                 internals: &mut local_backing.internals.0,
 
                 interrupt_signal_mem: get_interrupt_signal_mem(),
+
+                first_mem: local_backing.vm_memories[LocalMemoryIndex::new(0)],
             },
             local_functions: local_backing.local_functions.as_ptr(),
 
@@ -537,7 +546,7 @@ impl Ctx {
     }
 
     pub const fn offset_local_functions() -> u8 {
-        14 * (mem::size_of::<usize>() as u8)
+        15 * (mem::size_of::<usize>() as u8)
     }
 }
 
@@ -666,6 +675,9 @@ pub struct LocalMemory {
     /// This is either `*mut DynamicMemory`, `*mut StaticMemory`,
     /// or `*mut SharedStaticMemory`.
     pub memory: *mut (),
+
+    /// wat
+    pub vmctx: *mut Ctx,
 }
 
 // manually implemented because LocalMemory contains raw pointers