Merge branch 'master' into cranelift-update

# Conflicts:
#	lib/compiler-cranelift/Cargo.toml
#	lib/compiler-cranelift/src/debug/mod.rs
#	lib/compiler-cranelift/src/lib.rs
#	lib/compiler/src/unwind.rs
#	lib/engine-jit/src/code_memory.rs
#	lib/engine-jit/src/function_table.rs
#	lib/engine-jit/src/lib.rs
#	lib/wasm-common/Cargo.toml

lib/compiler-cranelift/src/trampoline/dynamic_function.rs

@@ -0,0 +1,127 @@
+//! A trampoline generator for calling dynamic host functions from Wasm.
+
+use super::binemit::TrampolineRelocSink;
+use crate::translator::{compiled_function_unwind_info, signature_to_cranelift_ir};
+use cranelift_codegen::ir::{
+    ExternalName, Function, InstBuilder, MemFlags, StackSlotData, StackSlotKind,
+};
+use cranelift_codegen::isa::TargetIsa;
+use cranelift_codegen::print_errors::pretty_error;
+use cranelift_codegen::Context;
+use cranelift_codegen::{binemit, ir};
+use std::cmp;
+use std::mem;
+
+use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
+use wasm_common::FunctionType;
+use wasmer_compiler::{CompileError, FunctionBody};
+use wasmer_runtime::VMOffsets;
+
+/// Create a trampoline for invoking a WebAssembly function.
+pub fn make_trampoline_dynamic_function(
+    isa: &dyn TargetIsa,
+    offsets: &VMOffsets,
+    fn_builder_ctx: &mut FunctionBuilderContext,
+    func_type: &FunctionType,
+) -> Result<FunctionBody, CompileError> {
+    let pointer_type = isa.pointer_type();
+    let frontend_config = isa.frontend_config();
+    let signature = signature_to_cranelift_ir(func_type, &frontend_config);
+    let mut stub_sig = ir::Signature::new(frontend_config.default_call_conv);
+    // Add the caller `vmctx` parameter.
+    stub_sig.params.push(ir::AbiParam::special(
+        pointer_type,
+        ir::ArgumentPurpose::VMContext,
+    ));
+
+    // Add the `values_vec` parameter.
+    stub_sig.params.push(ir::AbiParam::new(pointer_type));
+
+    // Compute the size of the values vector. The vmctx and caller vmctx are passed separately.
+    let value_size = mem::size_of::<u128>();
+    let values_vec_len =
+        (value_size * cmp::max(signature.params.len() - 1, signature.returns.len())) as u32;
+
+    let mut context = Context::new();
+    context.func = Function::with_name_signature(ExternalName::user(0, 0), signature.clone());
+
+    let ss = context.func.create_stack_slot(StackSlotData::new(
+        StackSlotKind::ExplicitSlot,
+        values_vec_len,
+    ));
+
+    {
+        let mut builder = FunctionBuilder::new(&mut context.func, fn_builder_ctx);
+        let block0 = builder.create_block();
+
+        builder.append_block_params_for_function_params(block0);
+        builder.switch_to_block(block0);
+        builder.seal_block(block0);
+
+        let values_vec_ptr_val = builder.ins().stack_addr(pointer_type, ss, 0);
+        let mflags = MemFlags::trusted();
+        // We only get the non-vmctx arguments
+        for i in 1..signature.params.len() {
+            let val = builder.func.dfg.block_params(block0)[i];
+            builder.ins().store(
+                mflags,
+                val,
+                values_vec_ptr_val,
+                ((i - 1) * value_size) as i32,
+            );
+        }
+
+        let block_params = builder.func.dfg.block_params(block0);
+        let vmctx_ptr_val = block_params[0];
+        let callee_args = vec![vmctx_ptr_val, values_vec_ptr_val];
+
+        let new_sig = builder.import_signature(stub_sig);
+
+        let mem_flags = ir::MemFlags::trusted();
+        let callee_value = builder.ins().load(
+            pointer_type,
+            mem_flags,
+            vmctx_ptr_val,
+            offsets.vmdynamicfunction_import_context_address() as i32,
+        );
+
+        builder
+            .ins()
+            .call_indirect(new_sig, callee_value, &callee_args);
+
+        let mflags = MemFlags::trusted();
+        let mut results = Vec::new();
+        for (i, r) in signature.returns.iter().enumerate() {
+            let load = builder.ins().load(
+                r.value_type,
+                mflags,
+                values_vec_ptr_val,
+                (i * value_size) as i32,
+            );
+            results.push(load);
+        }
+        builder.ins().return_(&results);
+        builder.finalize()
+    }
+
+    let mut code_buf = Vec::new();
+    let mut reloc_sink = TrampolineRelocSink {};
+    let mut trap_sink = binemit::NullTrapSink {};
+    let mut stackmap_sink = binemit::NullStackmapSink {};
+    context
+        .compile_and_emit(
+            isa,
+            &mut code_buf,
+            &mut reloc_sink,
+            &mut trap_sink,
+            &mut stackmap_sink,
+        )
+        .map_err(|error| CompileError::Codegen(pretty_error(&context.func, Some(isa), error)))?;
+
+    let unwind_info = compiled_function_unwind_info(isa, &context)?;
+
+    Ok(FunctionBody {
+        body: code_buf,
+        unwind_info,
+    })
+}