From 38a84342a2d9bdd89f85b9db77c9d7fb56b7398f Mon Sep 17 00:00:00 2001
From: Fabian <copy@copy.sh>
Date: Sun, 26 Aug 2018 19:47:02 -0500
Subject: [PATCH] Give Rust more indirect function slots and clean up the code

---
 src/browser/starter.js | 2 +-
 src/const.js           | 3 +++
 src/cpu.js             | 7 +++----
 src/rust/cpu2/cpu.rs   | 6 +++++-
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/browser/starter.js b/src/browser/starter.js
index 55ef3784..89b2c0d7 100644
--- a/src/browser/starter.js
+++ b/src/browser/starter.js
@@ -105,7 +105,7 @@ function V86Starter(options)
     //    }, this);
     //}
 
-    const wasm_table = new WebAssembly.Table({ element: "anyfunc", "initial": 0x10000 + 0x100 });
+    const wasm_table = new WebAssembly.Table({ element: "anyfunc", "initial": WASM_TABLE_SIZE + WASM_TABLE_OFFSET });
 
     var wasm_shared_funcs = {
         "__assert_fail": (condition, file, line, fun) => {
diff --git a/src/const.js b/src/const.js
index d9865c51..4c8c9e6a 100644
--- a/src/const.js
+++ b/src/const.js
@@ -358,6 +358,9 @@ const P_RUN_INTERPRETED = 4;
 /** @const */
 var WASM_TABLE_SIZE = 0x10000;
 
+/** @const */
+var WASM_TABLE_OFFSET = 1024;
+
 /** @const */
 var JIT_CACHE_ARRAY_SIZE = 0x40000;
 
diff --git a/src/cpu.js b/src/cpu.js
index 249f2610..fca9b98b 100644
--- a/src/cpu.js
+++ b/src/cpu.js
@@ -369,7 +369,7 @@ CPU.prototype.jit_force_generate = function(addr)
 CPU.prototype.jit_clear_func = function(index)
 {
     dbg_assert(index >= 0 && index < WASM_TABLE_SIZE);
-    this.wm.imports.env[WASM_EXPORT_TABLE_NAME + 0x100].set(index, null);
+    this.wm.imports.env[WASM_EXPORT_TABLE_NAME].set(index + WASM_TABLE_OFFSET, null);
 };
 
 CPU.prototype.get_state = function()
@@ -1318,7 +1318,7 @@ CPU.prototype.codegen_finalize = function(wasm_table_index, start, end, first_op
             first_opcode, state_flags);
 
         // The following will throw if f isn't an exported function
-        this.wm.imports["env"][WASM_EXPORT_TABLE_NAME].set(wasm_table_index + 0x100, f);
+        this.wm.imports["env"][WASM_EXPORT_TABLE_NAME].set(wasm_table_index + WASM_TABLE_OFFSET, f);
 
         if(this.test_hook_did_finalize_wasm)
         {
@@ -1498,11 +1498,10 @@ CPU.prototype.jit_clear_cache = function()
     this.jit_empty_cache();
 
     const table = this.wm.exports[WASM_EXPORT_TABLE_NAME] || this.wm.imports["env"][WASM_EXPORT_TABLE_NAME];
-    const offset = 0x100;
 
     for(let i = 0; i < WASM_TABLE_SIZE; i++)
     {
-        table.set(offset + i, null);
+        table.set(WASM_TABLE_OFFSET + i, null);
     }
 };
 
diff --git a/src/rust/cpu2/cpu.rs b/src/rust/cpu2/cpu.rs
index 78016b67..b490445b 100644
--- a/src/rust/cpu2/cpu.rs
+++ b/src/rust/cpu2/cpu.rs
@@ -33,6 +33,10 @@ use cpu2::modrm::{resolve_modrm16, resolve_modrm32};
 use cpu2::profiler::*;
 use cpu2::profiler::{profiler_stat_increment, profiler_stat_increment_by};
 
+/// The offset for our generated functions in the wasm table. Every index less than this is
+/// reserved for rustc's indirect functions
+pub const WASM_TABLE_OFFSET: u32 = 1024;
+
 #[derive(Copy, Clone)]
 #[repr(C)]
 pub union reg64 {
@@ -777,7 +781,7 @@ pub unsafe fn cycle_internal() -> () {
             wasm_table_index = (entry & 65535i32 as u32) as u16;
             initial_state = (entry >> 16i32) as u16;
             call_indirect1(
-                (wasm_table_index as u32).wrapping_add(256i32 as u32) as i32,
+                (wasm_table_index as u32).wrapping_add(WASM_TABLE_OFFSET as u32) as i32,
                 initial_state,
             );
             profiler_stat_increment_by(