Produce better object file

Cargo.toml

@@ -35,7 +35,7 @@ wasmtime-wast = { path = "lib/wast" }
 docopt = "1.0.1"
 serde = "1.0.75"
 serde_derive = "1.0.75"
-faerie = "0.6.0"
+faerie = "0.7.0"
 target-lexicon = { version = "0.2.0", default-features = false }
 pretty_env_logger = "0.3.0"
 file-per-thread-logger = "0.1.1"

lib/obj/Cargo.toml

@@ -14,5 +14,7 @@ edition = "2018"
 [dependencies]
 cranelift-codegen = "0.28.0"
 cranelift-entity = "0.28.0"
+cranelift-wasm = "0.28.0"
+wasmtime-runtime = { path = "../runtime" }
 wasmtime-environ = { path = "../environ" }
-faerie = "0.6.0"
+faerie = "0.7.0"

lib/obj/src/context.rs

@@ -0,0 +1,279 @@
+use cranelift_codegen::ir;
+use cranelift_codegen::isa::TargetFrontendConfig;
+use cranelift_entity::EntityRef;
+use cranelift_wasm::{FuncIndex, GlobalInit};
+use std::io::{Result, Write};
+use wasmtime_environ::{DataInitializer, Module, VMOffsets};
+use wasmtime_runtime::{
+    SignatureRegistry, VMGlobalDefinition, VMSharedSignatureIndex, VMTableDefinition,
+};
+
+/// Generates C code base on module metadata.
+pub fn generate_c_stubs(
+    header: &mut Vec<u8>,
+    code: &mut Vec<u8>,
+    name: &str,
+    module: &Module,
+    data_initializers: &[DataInitializer],
+    target_config: &TargetFrontendConfig,
+) -> Result<()> {
+    let ofs = VMOffsets::new(target_config.pointer_bytes(), &module);
+
+    let uppercase_name = String::from(name).to_uppercase();
+    writeln!(header, "#ifndef __{}_H", uppercase_name)?;
+    writeln!(header, "#define __{}_H", uppercase_name)?;
+    writeln!(header, "#include <stddef.h>")?;
+    writeln!(header, "#include <stdint.h>")?;
+    writeln!(header)?;
+
+    if !module.memory_plans.is_empty() {
+        if module.memory_plans.len() > 1 {
+            panic!("multiple memories not supported yet");
+        }
+        let (_, memory_plan) = module
+            .memory_plans
+            .iter()
+            .next()
+            .expect("at least one memory");
+        let size = memory_plan.memory.minimum << 16;
+        writeln!(header, "#define MEMORY_INIT_SIZE {}", size)?;
+    }
+
+    writeln!(header)?;
+    writeln!(header, "struct VMContext {{")?;
+    if ofs.num_signature_ids > 0 {
+        writeln!(header, "\tuint32_t\tsignatures[{}];", ofs.num_signature_ids)?;
+    }
+    if ofs.num_imported_functions > 0 {
+        writeln!(header, "\tstruct {{")?;
+        writeln!(header, "\t\tvoid\t*body;")?;
+        writeln!(header, "\t\tvoid\t*vmctx;")?;
+        writeln!(
+            header,
+            "\t}}\timported_functions[{}];",
+            ofs.num_imported_functions
+        )?;
+    }
+    if ofs.num_imported_tables > 0 {
+        writeln!(header, "\tstruct {{")?;
+        writeln!(header, "\t\tvoid\t*from;")?;
+        writeln!(header, "\t\tvoid\t*vmctx;")?;
+        writeln!(
+            header,
+            "\t}}\timported_tables[{}];",
+            ofs.num_imported_tables
+        )?;
+    }
+    if ofs.num_imported_memories > 0 {
+        writeln!(header, "\tstruct {{")?;
+        writeln!(header, "\t\tvoid\t*from;")?;
+        writeln!(header, "\t\tvoid\t*vmctx;")?;
+        writeln!(
+            header,
+            "\t}}\timported_memories[{}];",
+            ofs.num_imported_memories
+        )?;
+    }
+    if ofs.num_imported_globals > 0 {
+        writeln!(
+            header,
+            "\tvoid\t*imported_globals[{}];",
+            ofs.num_imported_globals
+        )?;
+    }
+    if ofs.num_defined_tables > 0 {
+        writeln!(header, "\tstruct {{")?;
+        writeln!(header, "\t\tvoid\t**base;")?;
+        writeln!(header, "\t\tsize_t\tcurrent_elements;")?;
+        writeln!(header, "\t}}\tdefined_tables[{}];", ofs.num_defined_tables)?;
+    }
+    if ofs.num_defined_memories > 0 {
+        writeln!(header, "\tstruct {{")?;
+        writeln!(header, "\t\tvoid\t*base;")?;
+        writeln!(header, "\t\tsize_t\tcurrent_length;")?;
+        writeln!(
+            header,
+            "\t}}\tdefined_memories[{}];",
+            ofs.num_defined_memories
+        )?;
+    }
+    if ofs.num_defined_globals > 0 {
+        writeln!(header, "\tstruct {{")?;
+        writeln!(header, "\t\tunion {{")?;
+        writeln!(header, "\t\t\tuint32_t\tu32;")?;
+        writeln!(header, "\t\t\tuint64_t\tu64;")?;
+        writeln!(header, "\t\t\tfloat\tf32;")?;
+        writeln!(header, "\t\t\tdouble\tf64;")?;
+        writeln!(header, "\t\t}};")?;
+        writeln!(
+            header,
+            "\t}}\tdefined_globals[{}];",
+            ofs.num_defined_globals
+        )?;
+    }
+    writeln!(header, "}};")?;
+    writeln!(header)?;
+    for i in 0..module.functions.len() {
+        if i < ofs.num_imported_functions as usize {
+            continue;
+        }
+        let signature = &module.signatures[module.functions[FuncIndex::from_u32(i as u32)]];
+        let get_type = |x: &ir::AbiParam| -> &str {
+            match x.value_type {
+                ir::types::I32 => "uint32_t",
+                ir::types::I64 => "uint64_t",
+                _ => panic!("unsupported type"),
+            }
+        };
+        let mut first = true;
+        for p in signature.returns.iter() {
+            if p.purpose != ir::ArgumentPurpose::Normal {
+                continue;
+            }
+            assert!(first);
+            first = false;
+            write!(header, "{}", get_type(p))?;
+        }
+        if first {
+            write!(header, "void")?;
+        }
+        write!(header, " _wasm_function_{}(", i)?;
+        let mut first = true;
+        for p in signature.params.iter() {
+            if first {
+                first = false;
+            } else {
+                write!(header, ", ")?;
+            }
+            match p.purpose {
+                ir::ArgumentPurpose::VMContext => {
+                    write!(header, "struct VMContext*")?;
+                }
+                ir::ArgumentPurpose::Normal => {
+                    write!(header, "{}", get_type(p))?;
+                }
+                _ => panic!("unsupported param type: {:?}", p.purpose),
+            }
+        }
+        writeln!(header, ");")?
+    }
+    if data_initializers.len() > 0 {
+        writeln!(header)?;
+        for i in 0..data_initializers.len() {
+            writeln!(header, "extern void *_memory_{};", i)?;
+        }
+    }
+    writeln!(header)?;
+    writeln!(
+        header,
+        "extern char _vmcontext_init[{}];",
+        ofs.size_of_vmctx()
+    )?;
+    writeln!(header, "void init_vm(struct VMContext *, void *, size_t);")?;
+    writeln!(header, "#endif // __{}_H", uppercase_name)?;
+
+    writeln!(code, "#include \"{}.h\"", name)?;
+    writeln!(code)?;
+    writeln!(code, "#include <string.h>")?;
+    writeln!(code)?;
+    writeln!(
+        code,
+        "void init_vm(struct VMContext *vmctx, void *memory, size_t memory_len) {{"
+    )?;
+    writeln!(
+        code,
+        "\tmemcpy(vmctx, _vmcontext_init, sizeof(_vmcontext_init));"
+    )?;
+    if ofs.num_defined_memories > 0 {
+        writeln!(code, "\tvmctx->defined_memories[0].base = memory;")?;
+        writeln!(
+            code,
+            "\tvmctx->defined_memories[0].current_length = memory_len;"
+        )?;
+    }
+
+    if data_initializers.len() > 0 {
+        writeln!(code)?;
+        for i in 0..data_initializers.len() {
+            let data_initializer = &data_initializers[i];
+            let offset = {
+                let addend = data_initializer.location.offset;
+                if let Some(global_index) = data_initializer.location.base {
+                    format!(
+                        "vmctx->defined_globals[{}].u32 + {}",
+                        global_index.index(),
+                        addend
+                    )
+                } else {
+                    format!("{}", addend)
+                }
+            };
+            let len = data_initializer.data.len();
+            writeln!(
+                code,
+                "\tmemcpy(memory + {}, _memory_{}, {});",
+                offset, i, len
+            )?;
+        }
+    }
+
+    writeln!(code, "}};")?;
+    Ok(())
+}
+
+pub struct TableRelocation {
+    pub index: usize,
+    pub offset: usize,
+}
+
+pub fn layout_vmcontext(
+    module: &Module,
+    target_config: &TargetFrontendConfig,
+) -> (Box<[u8]>, Box<[TableRelocation]>) {
+    let ofs = VMOffsets::new(target_config.pointer_bytes(), &module);
+    let out_len = ofs.size_of_vmctx() as usize;
+    let mut out = Vec::with_capacity(out_len);
+    out.resize(out_len, 0);
+
+    let mut signature_registry = SignatureRegistry::new();
+    for (index, sig) in module.signatures.iter() {
+        let offset = ofs.vmctx_vmshared_signature_id(index) as usize;
+        let id = signature_registry.register(sig);
+        unsafe {
+            let to = out.as_mut_ptr().add(offset) as *mut VMSharedSignatureIndex;
+            (*to) = id;
+        }
+    }
+
+    let num_tables_imports = module.imported_tables.len();
+    let mut table_relocs = Vec::with_capacity(module.table_plans.len() - num_tables_imports);
+    for (index, table) in module.table_plans.iter().skip(num_tables_imports) {
+        let def_index = module.defined_table_index(index).unwrap();
+        let offset = ofs.vmctx_vmtable_definition(def_index) as usize;
+        let current_elements = table.table.minimum as usize;
+        unsafe {
+            let to = out.as_mut_ptr().add(offset) as *mut VMTableDefinition;
+            (*to).current_elements = current_elements;
+        }
+        table_relocs.push(TableRelocation {
+            index: def_index.index(),
+            offset,
+        });
+    }
+
+    let num_globals_imports = module.imported_globals.len();
+    for (index, global) in module.globals.iter().skip(num_globals_imports) {
+        let def_index = module.defined_global_index(index).unwrap();
+        let offset = ofs.vmctx_vmglobal_definition(def_index) as usize;
+        let to = unsafe { out.as_mut_ptr().add(offset) as *mut VMGlobalDefinition };
+        match global.initializer {
+            GlobalInit::I32Const(x) => *unsafe { (*to).as_i32_mut() } = x,
+            GlobalInit::I64Const(x) => *unsafe { (*to).as_i64_mut() } = x,
+            GlobalInit::F32Const(x) => *unsafe { (*to).as_f32_bits_mut() } = x,
+            GlobalInit::F64Const(x) => *unsafe { (*to).as_f64_bits_mut() } = x,
+            _ => panic!("unsupported global type"),
+        }
+    }
+
+    (out.into_boxed_slice(), table_relocs.into_boxed_slice())
+}

lib/obj/src/data_segment.rs

@@ -0,0 +1,32 @@
+use faerie::{Artifact, Decl};
+use wasmtime_environ::DataInitializer;
+
+/// Declares data segment symbol
+pub fn declare_data_segment(
+    obj: &mut Artifact,
+    _data_initaliazer: &DataInitializer,
+    index: usize,
+) -> Result<(), String> {
+    let name = format!("_memory_{}", index);
+    obj.declare(
+        name,
+        Decl::Data {
+            writable: false,
+            global: false,
+        },
+    )
+    .map_err(|err| format!("{}", err))?;
+    Ok(())
+}
+
+/// Emit segment data and initialization location
+pub fn emit_data_segment(
+    obj: &mut Artifact,
+    data_initaliazer: &DataInitializer,
+    index: usize,
+) -> Result<(), String> {
+    let name = format!("_memory_{}", index);
+    obj.define(name, Vec::from(data_initaliazer.data))
+        .map_err(|err| format!("{}", err))?;
+    Ok(())
+}