From 7956084121622e44c64262bb8c8ececfbd7848b9 Mon Sep 17 00:00:00 2001
From: Tyler McMullen <tbmcmullen@gmail.com>
Date: Tue, 21 Nov 2017 17:08:31 -0800
Subject: [PATCH] Treat VmContext as positional when using Native CallConv
 (#195)

* Treat VMContext as standard positional argument when using Native CallConv.

This requires threading the CallConv through legalize_args and into ArgAssigner.

* Stash CallConv in the intel-specific Args struct, for use ArgAssigner.
---
 lib/cretonne/src/isa/intel/abi.rs | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/lib/cretonne/src/isa/intel/abi.rs b/lib/cretonne/src/isa/intel/abi.rs
index 3cd3dce931..e8be53e848 100644
--- a/lib/cretonne/src/isa/intel/abi.rs
+++ b/lib/cretonne/src/isa/intel/abi.rs
@@ -6,7 +6,7 @@ use regalloc::AllocatableSet;
 use settings as shared_settings;
 use super::registers::{GPR, FPR, RU};
 use abi::{ArgAction, ValueConversion, ArgAssigner, legalize_args};
-use ir::{AbiParam, ArgumentPurpose, ArgumentLoc, ArgumentExtension};
+use ir::{AbiParam, ArgumentPurpose, ArgumentLoc, ArgumentExtension, CallConv};
 use std::i32;
 
 /// Argument registers for x86-64
@@ -24,10 +24,11 @@ struct Args {
     fpr_limit: usize,
     fpr_used: usize,
     offset: u32,
+    call_conv: CallConv,
 }
 
 impl Args {
-    fn new(bits: u16, gpr: &'static [RU], fpr_limit: usize) -> Args {
+    fn new(bits: u16, gpr: &'static [RU], fpr_limit: usize, call_conv: CallConv) -> Args {
         Args {
             pointer_bytes: u32::from(bits) / 8,
             pointer_bits: bits,
@@ -37,6 +38,7 @@ impl Args {
             fpr_limit,
             fpr_used: 0,
             offset: 0,
+            call_conv: call_conv,
         }
     }
 }
@@ -66,8 +68,7 @@ impl ArgAssigner for Args {
         }
 
         // Handle special-purpose arguments.
-        // TODO: The registers below are for `spiderwasm`. Should we check the calling convention?
-        if ty.is_int() {
+        if ty.is_int() && self.call_conv == CallConv::SpiderWASM {
             match arg.purpose {
                 // This is SpiderMonkey's `WasmTlsReg`.
                 ArgumentPurpose::VMContext => {
@@ -112,15 +113,15 @@ pub fn legalize_signature(sig: &mut ir::Signature, flags: &shared_settings::Flag
 
     if flags.is_64bit() {
         bits = 64;
-        args = Args::new(bits, &ARG_GPRS, 8);
+        args = Args::new(bits, &ARG_GPRS, 8, sig.call_conv);
     } else {
         bits = 32;
-        args = Args::new(bits, &[], 0);
+        args = Args::new(bits, &[], 0, sig.call_conv);
     }
 
     legalize_args(&mut sig.params, &mut args);
 
-    let mut rets = Args::new(bits, &RET_GPRS, 2);
+    let mut rets = Args::new(bits, &RET_GPRS, 2, sig.call_conv);
     legalize_args(&mut sig.returns, &mut rets);
 }