https://gcc.gnu.org/g:85f924f470682b5c71b8bf501e6a143701303a93
commit 85f924f470682b5c71b8bf501e6a143701303a93
Author: Jakub Dupak <d...@jakubdupak.com>
Date: Wed Oct 18 22:54:37 2023 +0200
borrowck: BIR: handle break
gcc/rust/ChangeLog:
* checks/errors/borrowck/rust-bir-builder-expr-stmt.cc
(ExprStmtBuilder::visit): Push ctx.
(ExprStmtBuilder::setup_loop): Common loop infractructure setup.
* checks/errors/borrowck/rust-bir-builder-expr-stmt.h: Loop ctx.
* checks/errors/borrowck/rust-bir-builder-internal.h (struct
BuilderContext): Loop ctx.
Signed-off-by: Jakub Dupak <d...@jakubdupak.com>
Diff:
---
.../errors/borrowck/rust-bir-builder-expr-stmt.cc | 168 +++++++++++++++------
.../errors/borrowck/rust-bir-builder-expr-stmt.h | 2 +
.../errors/borrowck/rust-bir-builder-internal.h | 66 +++++---
3 files changed, 168 insertions(+), 68 deletions(-)
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.cc
b/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.cc
index 1487c853b49e..67b98e2254f9 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.cc
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.cc
@@ -258,11 +258,45 @@ ExprStmtBuilder::visit (HIR::FieldAccessExpr &expr)
void
ExprStmtBuilder::visit (HIR::BlockExpr &block)
{
+ BasicBlockId end_bb;
+
+ if (block.has_label ())
+ {
+ end_bb = new_bb ();
+ NodeId label
+ = block.get_label ().get_lifetime ().get_mappings ().get_nodeid ();
+ PlaceId label_var = ctx.place_db.add_temporary (lookup_type (block));
+ ctx.loop_and_label_stack.push_back ({false, label, label_var, end_bb,
0});
+ }
+
+ bool unreachable = false;
for (auto &stmt : block.get_statements ())
{
+ if (unreachable)
+ break;
stmt->accept_vis (*this);
+ if (ctx.get_current_bb ().is_terminated ())
+ unreachable = true;
+ }
+
+ if (block.has_label ())
+ {
+ auto label_info = ctx.loop_and_label_stack.back ();
+ if (block.has_expr () && !unreachable)
+ {
+ push_assignment (label_info.label_var,
+ visit_expr (*block.get_final_expr ()));
+ }
+ if (!ctx.get_current_bb ().is_terminated ())
+ {
+ add_jump_to (end_bb);
+ }
+ ctx.current_bb = end_bb;
+ ctx.loop_and_label_stack.pop_back ();
+
+ return_place (label_info.label_var);
}
- if (block.has_expr ())
+ else if (block.has_expr () && !unreachable)
{
return_place (visit_expr (*block.get_final_expr ()));
}
@@ -290,25 +324,36 @@ ExprStmtBuilder::visit (HIR::ContinueExpr &cont)
void
ExprStmtBuilder::visit (HIR::BreakExpr &brk)
{
- // BuilderContext::LabelledBlockCtx block_ctx{};
- // NodeId label = UNKNOWN_NODEID;
- // if (brk.has_label ())
- // {
- // if (!resolve_label (brk.get_label (), label))
- // return;
- // }
- // if (!find_block_ctx (label, block_ctx))
- // {
- // rust_error_at (brk.get_locus (), "unresolved labelled block");
- // }
- //
- // if (brk.has_break_expr ())
- // {
- // brk.get_expr ()->accept_vis (*this);
- // push_assignment (block_ctx.label_var, new Operator<1>
({translated}));
- // }
- //
- // add_jump_to (block_ctx.break_bb);
+ BuilderContext::LoopAndLabelInfo info;
+ if (brk.has_label ())
+ {
+ NodeId label = resolve_label (brk.get_label ());
+ auto lookup
+ = std::find_if (ctx.loop_and_label_stack.rbegin (),
+ ctx.loop_and_label_stack.rend (),
+ [label] (const BuilderContext::LoopAndLabelInfo &info) {
+ return info.label == label;
+ });
+ rust_assert (lookup != ctx.loop_and_label_stack.rend ());
+ info = *lookup;
+ }
+ else
+ {
+ auto lookup
+ = std::find_if (ctx.loop_and_label_stack.rbegin (),
+ ctx.loop_and_label_stack.rend (),
+ [] (const BuilderContext::LoopAndLabelInfo &info) {
+ return info.is_loop;
+ });
+ rust_assert (lookup != ctx.loop_and_label_stack.rend ());
+ info = *lookup;
+ }
+ if (brk.has_break_expr ())
+ {
+ push_assignment (info.label_var, visit_expr (*brk.get_expr ()));
+ }
+ add_jump_to (info.break_bb);
+ // No code allowed after break. No BB starts - would be empty.
}
void
@@ -370,60 +415,87 @@ ExprStmtBuilder::visit (HIR::UnsafeBlockExpr &expr)
rust_sorry_at (expr.get_locus (), "unsafe blocks are not supported");
}
+BuilderContext::LoopAndLabelInfo &
+ExprStmtBuilder::setup_loop (HIR::BaseLoopExpr &expr)
+{
+ NodeId label = (expr.has_loop_label ())
+ ? resolve_label (expr.get_loop_label ())
+ : UNKNOWN_NODEID;
+ PlaceId label_var = ctx.place_db.add_temporary (lookup_type (expr));
+
+ BasicBlockId continue_bb = new_bb ();
+ BasicBlockId break_bb = new_bb ();
+ ctx.loop_and_label_stack.push_back (
+ {true, label, label_var, break_bb, continue_bb});
+ return ctx.loop_and_label_stack.back ();
+}
+
void
ExprStmtBuilder::visit (HIR::LoopExpr &expr)
{
- // PlaceId label_var = ctx.place_db.add_temporary (nullptr);
- // NodeId label;
- // if (!resolve_label (expr.get_loop_label (), label))
- // return;
- // ctx.label_place_map.emplace (label, label_var);
- //
- // expr.get_loop_block ()->accept_vis (*this);
- //
- // translated = label_var;
+ auto loop = setup_loop (expr);
+
+ add_jump_to (loop.continue_bb);
+
+ ctx.current_bb = loop.continue_bb;
+ (void) visit_expr (*expr.get_loop_block ());
+ add_jump_to (loop.continue_bb);
+
+ ctx.current_bb = loop.break_bb;
}
+
void
ExprStmtBuilder::visit (HIR::WhileLoopExpr &expr)
{
- // // TODO: Desugar in AST->HIR ???
- // PlaceId label_var = ctx.place_db.add_temporary (nullptr);
- // NodeId label;
- // if (!resolve_label (expr.get_loop_label (), label))
- // return;
- // ctx.label_place_map.emplace (label, label_var);
- //
- // expr.get_predicate_expr ()->accept_vis (*this);
- //
- // expr.get_loop_block ()->accept_vis (*this);
- //
- // translated = label_var;
+ auto loop = setup_loop (expr);
+
+ add_jump_to (loop.continue_bb);
+
+ ctx.current_bb = loop.continue_bb;
+ auto cond_val = visit_expr (*expr.get_predicate_expr ());
+ auto body_bb = new_bb ();
+ push_switch (cond_val, {body_bb, loop.break_bb});
+
+ ctx.current_bb = body_bb;
+ (void) visit_expr (*expr.get_loop_block ());
+ add_jump_to (loop.continue_bb);
+
+ ctx.current_bb = loop.break_bb;
}
+
void
ExprStmtBuilder::visit (HIR::WhileLetLoopExpr &expr)
{
// TODO: Desugar in AST->HIR
+ rust_sorry_at (expr.get_locus (), "while let loops are not yet supported");
}
+
void
ExprStmtBuilder::visit (HIR::IfExpr &expr)
{
// If without else cannot return a non-unit value (see [E0317]).
+ if (expr.get_if_block ()->statements.empty ())
+ return;
+
push_switch (visit_expr (*expr.get_if_condition ()));
BasicBlockId if_block = ctx.current_bb;
ctx.current_bb = new_bb ();
+ BasicBlockId then_start_block = ctx.current_bb;
(void) visit_expr (*expr.get_if_block ());
- BasicBlockId then_block = ctx.current_bb;
+ BasicBlockId then_end_block = ctx.current_bb;
ctx.current_bb = new_bb ();
BasicBlockId final_block = ctx.current_bb;
return_unit (expr);
// Jumps are added at the end to match rustc MIR order for easier comparison.
- add_jump (if_block, then_block);
+ add_jump (if_block, then_start_block);
add_jump (if_block, final_block);
- add_jump (then_block, final_block);
+
+ if (!ctx.basic_blocks[then_end_block].is_terminated ())
+ add_jump (then_end_block, final_block);
}
void
@@ -451,8 +523,11 @@ ExprStmtBuilder::visit (HIR::IfExprConseqElse &expr)
// Jumps are added at the end to match rustc MIR order for easier comparison.
add_jump (if_block, then_block);
add_jump (if_block, else_block);
- add_jump (then_block, final_block);
- add_jump (else_block, final_block);
+
+ if (!ctx.basic_blocks[then_block].is_terminated ())
+ add_jump (then_block, final_block);
+ if (!ctx.basic_blocks[else_block].is_terminated ())
+ add_jump (else_block, final_block);
}
void
ExprStmtBuilder::visit (HIR::IfLetExpr &expr)
@@ -573,6 +648,5 @@ ExprStmtBuilder::visit (HIR::ExprStmt &stmt)
{
(void) visit_expr (*stmt.get_expr ());
}
-
} // namespace BIR
} // namespace Rust
\ No newline at end of file
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.h
b/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.h
index f46cba5f9684..e5707c31f8d3 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.h
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-builder-expr-stmt.h
@@ -46,6 +46,8 @@ private:
return result;
}
+ BuilderContext::LoopAndLabelInfo &setup_loop (HIR::BaseLoopExpr &expr);
+
protected: // Expr
// TODO: test when compiles
void visit (HIR::ClosureExpr &expr) override;
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-builder-internal.h
b/gcc/rust/checks/errors/borrowck/rust-bir-builder-internal.h
index 48116d8c351c..ef48cba7b80b 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-builder-internal.h
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-builder-internal.h
@@ -55,12 +55,21 @@ public:
struct BuilderContext
{
- struct LabelledBlockCtx
+ struct LoopAndLabelInfo
{
- NodeId label; // UNKNOWN_NODEID if no label
- PlaceId label_var;
+ bool is_loop; // Loop or labelled block
+ NodeId label; // UNKNOWN_NODEID if no label (loop)
+ PlaceId label_var; // For break with value.
BasicBlockId break_bb;
BasicBlockId continue_bb; // Only valid for loops
+
+ LoopAndLabelInfo (bool is_loop = false, NodeId label = UNKNOWN_NODEID,
+ PlaceId label_var = INVALID_PLACE,
+ BasicBlockId break_bb = INVALID_BB,
+ BasicBlockId continue_bb = INVALID_BB)
+ : is_loop (is_loop), label (label), label_var (label_var),
+ break_bb (break_bb), continue_bb (continue_bb)
+ {}
};
// Context
@@ -83,7 +92,7 @@ struct BuilderContext
*/
std::unordered_map<NodeId, PlaceId> label_place_map;
- std::vector<LabelledBlockCtx> loop_stack;
+ std::vector<LoopAndLabelInfo> loop_and_label_stack;
public:
BuilderContext ()
@@ -115,6 +124,18 @@ public:
}
rust_unreachable ();
};
+
+ const LoopAndLabelInfo &lookup_label (NodeId label)
+ {
+ auto label_match = [label] (const LoopAndLabelInfo &info) {
+ return info.label != UNKNOWN_NODEID && info.label == label;
+ };
+
+ auto found = std::find_if (loop_and_label_stack.rbegin (),
+ loop_and_label_stack.rend (), label_match);
+ rust_assert (found != loop_and_label_stack.rend ());
+ return *found;
+ }
};
// Common infrastructure for building BIR from HIR.
@@ -195,10 +216,13 @@ protected:
push_assignment (tmp, rhs);
}
- void push_switch (PlaceId switch_val)
+ void push_switch (PlaceId switch_val,
+ std::initializer_list<BasicBlockId> destinations = {})
{
ctx.get_current_bb ().statements.emplace_back (Node::Kind::SWITCH,
switch_val);
+ ctx.get_current_bb ().successors.insert (
+ ctx.get_current_bb ().successors.end (), destinations);
}
void push_storage_dead (PlaceId place)
@@ -235,15 +259,14 @@ protected:
void add_jump_to (BasicBlockId bb) { add_jump (ctx.current_bb, bb); }
protected:
- template <typename T> bool resolve_label (T &label, NodeId &resolved_label)
+ template <typename T> NodeId resolve_label (T &expr)
{
- if (!ctx.resolver.lookup_resolved_label (
- label.get_mappings ().get_nodeid (), &resolved_label))
- {
- rust_error_at (label.get_locus (), "unresolved label");
- return false;
- }
- return true;
+ NodeId resolved_label;
+ bool ok
+ = ctx.resolver.lookup_resolved_label (expr.get_mappings ().get_nodeid (),
+ &resolved_label);
+ rust_assert (ok);
+ return resolved_label;
}
template <typename T>
@@ -261,21 +284,22 @@ protected:
return true;
}
- bool find_block_ctx (NodeId label, BuilderContext::LabelledBlockCtx &block)
+ bool find_block_ctx (NodeId label, BuilderContext::LoopAndLabelInfo &block)
{
- if (ctx.loop_stack.empty ())
+ if (ctx.loop_and_label_stack.empty ())
return false;
if (label == UNKNOWN_NODEID)
{
- block = ctx.loop_stack.back ();
+ block = ctx.loop_and_label_stack.back ();
return true;
}
auto found
- = std::find_if (ctx.loop_stack.rbegin (), ctx.loop_stack.rend (),
- [&label] (const BuilderContext::LabelledBlockCtx &block) {
+ = std::find_if (ctx.loop_and_label_stack.rbegin (),
+ ctx.loop_and_label_stack.rend (),
+ [&label] (const BuilderContext::LoopAndLabelInfo &block) {
return block.label == label;
});
- if (found == ctx.loop_stack.rend ())
+ if (found == ctx.loop_and_label_stack.rend ())
return false;
block = *found;
return true;
@@ -318,8 +342,8 @@ protected:
}
}
- /** Dereferences the `translated` place until it is at most one reference and
- * return the base type. */
+ /** Dereferences the `translated` place until it is at most one reference
+ * and return the base type. */
TyTy::BaseType *autoderef (PlaceId &place)
{
auto ty = ctx.place_db[place].tyty;
