Used `IndexVec` for BasicBlocks

gcc/rust/ChangeLog:

	* checks/errors/borrowck/rust-bir-builder-expr-stmt.cc
	(ExprStmtBuilder::visit): Use strong type as index and
	remove access to numeric value.
	* checks/errors/borrowck/rust-bir-builder-internal.h
	(struct BuilderContext): Likewise.
	* checks/errors/borrowck/rust-bir-dump.cc (simplify_cfg):
	Likewise.
	(Dump::go): Likewise.
	(Dump::visit): Likewise.
	* checks/errors/borrowck/rust-bir-fact-collector.h
	(class FactCollector): Likewise.
	(points): Likewise.
	* checks/errors/borrowck/rust-bir.h (struct BasicBlockId): Used
	IndexVec for BasicBlocks.
	(struct Function): Likewise.
	* checks/errors/borrowck/rust-borrow-checker-diagnostics.cc
	(BorrowCheckerDiagnostics::get_statement): Change the extracted
	index to strong type.

Signed-off-by: Kushal Pal <kushalpal109@gmail.com>

6 files changed, 22 insertions, 23 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 5014566..c11cff0 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
@@ -565,7 +565,7 @@ ExprStmtBuilder::visit (HIR::IfExpr &expr)
   add_jump (if_block, then_start_block);
   add_jump (if_block, final_block);
 
-  auto &then_end_bb = ctx.basic_blocks[then_end_block.value];
+  auto &then_end_bb = ctx.basic_blocks[then_end_block];
   if (then_end_bb.is_goto_terminated () && then_end_bb.successors.empty ())
     add_jump (then_end_block, final_block);
 }
@@ -602,11 +602,11 @@ ExprStmtBuilder::visit (HIR::IfExprConseqElse &expr)
   add_jump (if_end_bb, then_start_bb);
   add_jump (if_end_bb, else_start_bb);
 
-  auto &then_bb = ctx.basic_blocks[then_end_bb.value];
+  auto &then_bb = ctx.basic_blocks[then_end_bb];
   if (then_bb.is_goto_terminated () && then_bb.successors.empty ())
     add_jump (then_end_bb, final_start_bb);
 
-  auto &else_bb = ctx.basic_blocks[else_end_bb.value];
+  auto &else_bb = ctx.basic_blocks[else_end_bb];
   if (else_bb.is_goto_terminated () && else_bb.successors.empty ())
     add_jump (else_end_bb, final_start_bb);
 }
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 694b2d6..8de6b8b 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-builder-internal.h
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-builder-internal.h
@@ -76,7 +76,7 @@ struct BuilderContext
   Resolver::Resolver &resolver;
 
   // BIR output
-  std::vector<BasicBlock> basic_blocks;
+  BasicBlocks basic_blocks;
   BasicBlockId current_bb = ENTRY_BASIC_BLOCK;
 
   /**
@@ -107,7 +107,7 @@ public:
     basic_blocks.emplace_back (); // StartBB
   }
 
-  BasicBlock &get_current_bb () { return basic_blocks[current_bb.value]; }
+  BasicBlock &get_current_bb () { return basic_blocks[current_bb]; }
 
   const LoopAndLabelCtx &lookup_label (NodeId label)
   {
@@ -378,7 +378,7 @@ protected: // CFG helpers
 
   void add_jump (BasicBlockId from, BasicBlockId to)
   {
-    ctx.basic_blocks[from.value].successors.emplace_back (to);
+    ctx.basic_blocks[from].successors.emplace_back (to);
   }
 
   void add_jump_to (BasicBlockId bb) { add_jump (ctx.current_bb, bb); }
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-dump.cc b/gcc/rust/checks/errors/borrowck/rust-bir-dump.cc
index 86bc5b1..5bcf224 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-dump.cc
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-dump.cc
@@ -84,7 +84,7 @@ simplify_cfg (Function &func, std::vector<BasicBlockId> &bb_fold_map)
       // BB0 cannot be folded as it is an entry block.
       for (BasicBlockId i = {1}; i.value < func.basic_blocks.size (); ++i.value)
 	{
-	  const BasicBlock &bb = func.basic_blocks[bb_fold_map[i.value].value];
+	  const BasicBlock &bb = func.basic_blocks[bb_fold_map[i.value]];
 	  if (bb.statements.empty () && bb.is_goto_terminated ())
 	    {
 	      auto dst = bb.successors.at (0);
@@ -149,13 +149,13 @@ Dump::go (bool enable_simplify_cfg)
       if (bb_fold_map[statement_bb.value] != statement_bb)
 	continue; // This BB was folded.
 
-      if (func.basic_blocks[statement_bb.value].statements.empty ()
-	  && func.basic_blocks[statement_bb.value].successors.empty ())
+      if (func.basic_blocks[statement_bb].statements.empty ()
+	  && func.basic_blocks[statement_bb].successors.empty ())
 	continue;
 
       bb_terminated = false;
 
-      BasicBlock &bb = func.basic_blocks[statement_bb.value];
+      BasicBlock &bb = func.basic_blocks[statement_bb];
       stream << "\n";
       stream << indentation << "bb" << bb_fold_map[statement_bb.value].value
 	     << ": {\n";
@@ -192,8 +192,7 @@ Dump::visit (const Statement &stmt)
       stream << "switchInt(";
       visit_move_place (stmt.get_place ());
       stream << ") -> [";
-      print_comma_separated (stream,
-			     func.basic_blocks[statement_bb.value].successors,
+      print_comma_separated (stream, func.basic_blocks[statement_bb].successors,
 			     [this] (BasicBlockId succ) {
 			       stream << "bb" << bb_fold_map[succ.value].value;
 			     });
@@ -207,9 +206,8 @@ Dump::visit (const Statement &stmt)
     case Statement::Kind::GOTO:
       stream
 	<< "goto -> bb"
-	<< bb_fold_map
-	     [func.basic_blocks[statement_bb.value].successors.at (0).value]
-	       .value;
+	<< bb_fold_map[func.basic_blocks[statement_bb].successors.at (0).value]
+	     .value;
       bb_terminated = true;
       break;
     case Statement::Kind::STORAGE_DEAD:
@@ -329,8 +327,7 @@ Dump::visit (const CallExpr &expr)
 			   visit_move_place (place_id);
 			 });
   stream << ") -> [";
-  print_comma_separated (stream,
-			 func.basic_blocks[statement_bb.value].successors,
+  print_comma_separated (stream, func.basic_blocks[statement_bb].successors,
 			 [this] (BasicBlockId succ) {
 			   stream << "bb" << bb_fold_map[succ.value].value;
 			 });
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir-fact-collector.h b/gcc/rust/checks/errors/borrowck/rust-bir-fact-collector.h
index 0d59f80..0c3e733 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir-fact-collector.h
+++ b/gcc/rust/checks/errors/borrowck/rust-bir-fact-collector.h
@@ -40,7 +40,7 @@ class FactCollector : public Visitor
 
   // Read-only context.
   const PlaceDB &place_db;
-  const std::vector<BasicBlock> &basic_blocks;
+  const BasicBlocks &basic_blocks;
   const PlaceId first_local;
   const location_t location;
 
@@ -212,7 +212,7 @@ protected: // Main collection entry points (for different categories).
     for (current_bb = ENTRY_BASIC_BLOCK;
 	 current_bb.value < basic_blocks.size (); ++current_bb.value)
       {
-	auto &bb = basic_blocks[current_bb.value];
+	auto &bb = basic_blocks[current_bb];
 	for (current_stmt = 0; current_stmt < bb.statements.size ();
 	     ++current_stmt)
 	  {
@@ -393,7 +393,7 @@ protected: // Main collection entry points (for different categories).
 protected: // Statement visitor helpers
   WARN_UNUSED_RESULT const BasicBlock &get_current_bb () const
   {
-    return basic_blocks[current_bb.value];
+    return basic_blocks[current_bb];
   }
 
   WARN_UNUSED_RESULT static Polonius::Point
diff --git a/gcc/rust/checks/errors/borrowck/rust-bir.h b/gcc/rust/checks/errors/borrowck/rust-bir.h
index 4bfc147..e303a84 100644
--- a/gcc/rust/checks/errors/borrowck/rust-bir.h
+++ b/gcc/rust/checks/errors/borrowck/rust-bir.h
@@ -30,6 +30,8 @@ namespace Rust {
 namespace BIR {
 
 struct BasicBlock;
+struct BasicBlockId;
+using BasicBlocks = IndexVec<BasicBlockId, BasicBlock>;
 class Statement;
 class AbstractExpr;
 
@@ -42,7 +44,7 @@ struct Function
 {
   PlaceDB place_db;
   std::vector<PlaceId> arguments;
-  std::vector<BasicBlock> basic_blocks;
+  BasicBlocks basic_blocks;
   FreeRegions universal_regions;
   std::vector<std::pair<FreeRegion, FreeRegion>> universal_region_bounds;
   std::unordered_map<Polonius::Origin, HIR::LifetimeParam *> region_hir_map;
diff --git a/gcc/rust/checks/errors/borrowck/rust-borrow-checker-diagnostics.cc b/gcc/rust/checks/errors/borrowck/rust-borrow-checker-diagnostics.cc
index 4002ed4..6c67706 100644
--- a/gcc/rust/checks/errors/borrowck/rust-borrow-checker-diagnostics.cc
+++ b/gcc/rust/checks/errors/borrowck/rust-borrow-checker-diagnostics.cc
@@ -135,8 +135,8 @@ BorrowCheckerDiagnostics::get_statement (Polonius::Point point)
   // assert that the extracted indexes are valid
   rust_assert (bb_index < bir_function.basic_blocks.size ());
   rust_assert (statement_index
-	       < bir_function.basic_blocks[bb_index].statements.size ());
-  return bir_function.basic_blocks[bb_index].statements[statement_index];
+	       < bir_function.basic_blocks[{bb_index}].statements.size ());
+  return bir_function.basic_blocks[{bb_index}].statements[statement_index];
 }
 
 const BIR::Loan &