Various fixes.

src/alloy/backend/x64/lowering/lowering_sequences.cc

@@ -189,7 +189,7 @@ void IssueCall(X64Emitter& e, FunctionInfo* symbol_info, uint32_t flags) {
   }
   if (flags & CALL_TAIL) {
     // TODO(benvanik): adjust stack?
-    e.add(e.rsp, 0x40);
+    e.add(e.rsp, 72);
     e.jmp(e.rax);
   } else {
     e.call(e.rax);
@@ -210,7 +210,7 @@ void IssueCallIndirect(X64Emitter& e, Value* target, uint32_t flags) {
   e.mov(e.rdx, e.qword[e.rcx + 8]); // membase
   if (flags & CALL_TAIL) {
     // TODO(benvanik): adjust stack?
-    e.add(e.rsp, 0x40);
+    e.add(e.rsp, 72);
     e.jmp(e.rax);
   } else {
     e.call(e.rax);
@@ -2844,8 +2844,16 @@ table->AddSequence(OPCODE_COMPARE_EXCHANGE, [](X64Emitter& e, Instr*& i) {
 });
 
 table->AddSequence(OPCODE_ATOMIC_EXCHANGE, [](X64Emitter& e, Instr*& i) {
-  if (IsIntType(i->dest->type)) {
-    UNIMPLEMENTED_SEQ();
+  if (i->dest->type == INT32_TYPE) {
+    // dest = old_value = InterlockedExchange(src1 = address, src2 = new_value);
+    Reg32 dest, src2;
+    Reg64 src1;
+    e.BeginOp(i->dest, dest, REG_DEST,
+              i->src1.value, src1, 0,
+              i->src2.value, src2, 0);
+    e.mov(dest, src2);
+    e.xchg(e.dword[src1], dest);
+    e.EndOp(dest, src1, src2);
   } else {
     ASSERT_INVALID_TYPE();
   }

src/alloy/backend/x64/lowering/op_utils.inl

@@ -17,6 +17,8 @@ namespace {
 #define LIKE_REG(dest, like) Reg(dest.getIdx(), dest.getKind(), like.getBit(), false)
 #define NAX_LIKE(like) Reg(e.rax.getIdx(), e.rax.getKind(), like.getBit(), false)
 
+#define STASH_OFFSET 48
+
 // If we are running with tracing on we have to store the EFLAGS in the stack,
 // otherwise our calls out to C to print will clear it before DID_CARRY/etc
 // can get the value.
@@ -24,7 +26,7 @@ namespace {
 
 void LoadEflags(X64Emitter& e) {
 #if STORE_EFLAGS
-  e.mov(e.eax, e.dword[e.rsp + 40]);
+  e.mov(e.eax, e.dword[e.rsp + STASH_OFFSET]);
   e.push(e.ax);
   e.popf();
 #else
@@ -34,7 +36,7 @@ void LoadEflags(X64Emitter& e) {
 void StoreEflags(X64Emitter& e) {
 #if STORE_EFLAGS
   e.pushf();
-  e.pop(e.word[e.rsp + 40]);
+  e.pop(e.word[e.rsp + STASH_OFFSET]);
 #else
   // EFLAGS should have CA set?
   // (so long as we don't fuck with it)
@@ -43,7 +45,7 @@ void StoreEflags(X64Emitter& e) {
 
 Address Stash(X64Emitter& e, const Xmm& r) {
   // TODO(benvanik): ensure aligned.
-  auto addr = e.ptr[e.rsp + 48];
+  auto addr = e.ptr[e.rsp + STASH_OFFSET];
   e.movups(addr, r);
   return addr;
 }

src/alloy/backend/x64/x64_code_cache.cc

@@ -216,7 +216,7 @@ void X64CodeChunk::AddTableEntry(uint8_t* code, size_t code_size) {
   // TODO(benvanik): take as parameters?
   bool has_prolog = true;
   uint8_t prolog_size = 4;
-  uint8_t stack_bytes = 64;
+  uint8_t stack_bytes = 72;
 
   // http://msdn.microsoft.com/en-us/library/ddssxxy8.aspx
   UNWIND_INFO* unwind_info = (UNWIND_INFO*)(buffer + unwind_info_offset);

src/alloy/backend/x64/x64_emitter.cc

@@ -132,7 +132,7 @@ int X64Emitter::Emit(HIRBuilder* builder) {
   //     X64CodeCache, which dynamically generates exception information.
   //     Adding or changing anything here must be matched!
   const bool emit_prolog = true;
-  const size_t stack_size = 64;
+  const size_t stack_size = 72;
   if (emit_prolog) {
     mov(qword[rsp + 8], rcx);
     sub(rsp, stack_size);
@@ -238,7 +238,8 @@ void X64Emitter::EvictStaleRegisters() {
 
     // Register is live, not active. Check and see if we get rid of it.
     auto v = reg_state_.reg_values[n];
-    if (v->last_use->ordinal < current_ordinal) {
+    if (!v->last_use ||
+        v->last_use->ordinal < current_ordinal) {
       reg_state_.reg_values[n] = NULL;
       v->reg = -1;
       continue;

src/alloy/frontend/ppc/ppc_emit_memory.cc

@@ -891,7 +891,8 @@ XEEMITTER(stfiwx,       0x7C0007AE, X  )(PPCHIRBuilder& f, InstrData& i) {
   // EA <- b + (RB)
   // MEM(EA, 4) <- (FRS)[32:63]
   Value* ea = CalculateEA_0(f, i.X.RA, i.X.RB);
-  f.Store(ea, f.ByteSwap(f.Cast(f.LoadFPR(i.X.RT), INT32_TYPE)));
+  f.Store(ea, f.ByteSwap(
+      f.Truncate(f.Cast(f.LoadFPR(i.X.RT), INT64_TYPE), INT32_TYPE)));
   return 0;
 }