From 67ce86fd06cee81d3f875da09eb1a2d9b48edbbf Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@ucc.asn.au>
Date: Fri, 8 Sep 2017 17:13:55 +0800
Subject: MIR Gen - Fix box drop flags

---
 src/mir/mir.cpp         |  2 +-
 src/mir/mir_builder.cpp | 22 +++-------------------
 src/mir/optimise.cpp    | 13 ++++++++++---
 3 files changed, 14 insertions(+), 23 deletions(-)

(limited to 'src')

diff --git a/src/mir/mir.cpp b/src/mir/mir.cpp
index 09e978f9..6af64001 100644
--- a/src/mir/mir.cpp
+++ b/src/mir/mir.cpp
@@ -490,7 +490,7 @@ namespace MIR {
             if(e.kind == ::MIR::eDropKind::SHALLOW)
                 os << " SHALLOW";
             if(e.flag_idx != ~0u)
-                os << "IF df$" << e.flag_idx;
+                os << " IF df$" << e.flag_idx;
             os << ")";
             ),
         (ScopeEnd,
diff --git a/src/mir/mir_builder.cpp b/src/mir/mir_builder.cpp
index 97942ba2..1e72282a 100644
--- a/src/mir/mir_builder.cpp
+++ b/src/mir/mir_builder.cpp
@@ -2033,27 +2033,11 @@ VarState& MirBuilder::get_val_state_mut(const Span& sp, const ::MIR::LValue& lv)
 
         if( is_box )
         {
-            ::MIR::LValue   inner_lv;
-            // 1. If the inner lvalue isn't a slot with move information, move out of the lvalue into a temporary (with standard temp scope)
-            TU_MATCH_DEF( ::MIR::LValue, (*e.val), (ei),
-            (
-                with_val_type(sp, *e.val, [&](const auto& ty){ inner_lv = this->new_temporary(ty); });
-                this->push_stmt_assign(sp, inner_lv.clone(), ::MIR::RValue( mv$(*e.val) ));
-                *e.val = inner_lv.clone();
-                ),
-            (Argument,
-                inner_lv = ::MIR::LValue(ei);
-                ),
-            (Local,
-                inner_lv = ::MIR::LValue(ei);
-                )
-            )
-            // 2. Mark the slot as requiring only a shallow drop
-            ::std::vector<VarState> inner;
-            inner.push_back(VarState::make_Valid({}));
-            auto& ivs = get_val_state_mut(sp, inner_lv);
+            auto& ivs = get_val_state_mut(sp, *e.val);
             if( ! ivs.is_MovedOut() )
             {
+                ::std::vector<VarState> inner;
+                inner.push_back(VarState::make_Valid({}));
                 unsigned int drop_flag = (ivs.is_Optional() ? ivs.as_Optional() : ~0u);
                 ivs = VarState::make_MovedOut({ box$(VarState::make_Valid({})), drop_flag });
             }
diff --git a/src/mir/optimise.cpp b/src/mir/optimise.cpp
index 34a516de..d99c5b7c 100644
--- a/src/mir/optimise.cpp
+++ b/src/mir/optimise.cpp
@@ -24,7 +24,7 @@
 #define DUMP_AFTER_PASS     1
 
 #define DUMP_AFTER_DONE     0
-#define CHECK_AFTER_DONE    1
+#define CHECK_AFTER_DONE    2   // 1 = Check before GC, 2 = check before and after GC
 
 namespace {
     ::MIR::BasicBlockId get_new_target(const ::MIR::TypeResolve& state, ::MIR::BasicBlockId bb)
@@ -520,6 +520,10 @@ void MIR_OptimiseMin(const StaticTraitResolve& resolve, const ::HIR::ItemPath& p
     MIR_Optimise_GarbageCollect(state, fcn);
     //MIR_Validate_Full(resolve, path, fcn, args, ret_type);
     MIR_SortBlocks(resolve, path, fcn);
+
+#if CHECK_AFTER_DONE > 1
+    MIR_Validate(resolve, path, fcn, args, ret_type);
+#endif
     return ;
 }
 void MIR_Optimise(const StaticTraitResolve& resolve, const ::HIR::ItemPath& path, ::MIR::Function& fcn, const ::HIR::Function::args_t& args, const ::HIR::TypeRef& ret_type)
@@ -631,6 +635,9 @@ void MIR_Optimise(const StaticTraitResolve& resolve, const ::HIR::ItemPath& path
     //MIR_Validate_Full(resolve, path, fcn, args, ret_type);
 
     MIR_SortBlocks(resolve, path, fcn);
+#if CHECK_AFTER_DONE > 1
+    MIR_Validate(resolve, path, fcn, args, ret_type);
+#endif
 }
 
 // --------------------------------------------------------------------
@@ -2720,11 +2727,11 @@ bool MIR_Optimise_GarbageCollect(::MIR::TypeResolve& state, ::MIR::Function& fcn
                     if( se->flag_idx != ~0u && df_rewrite_table[se->flag_idx] == ~0u)
                     {
                         if( fcn.drop_flags.at(se->flag_idx) ) {
-                            DEBUG(state << "Remove flag from " << stmt);
+                            DEBUG(state << "Remove flag from " << stmt << " - Flag never set and default true");
                             se->flag_idx = ~0u;
                         }
                         else {
-                            DEBUG(state << "Remove " << stmt);
+                            DEBUG(state << "Remove " << stmt << " - Flag never set and default false");
                             to_remove_statements[stmt_idx] = true;
                             continue ;
                         }
-- 
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