core: Use anonymous name for variables if unspecified

The current default prefix is only derived from the instruction type,
which is not helpful during the comprehension of the IR. Changing to
anonymous names (e.g. %1) helps understand that the variable is only
needed as part of a larger (possibly named) expression.

nac3artiq/src/codegen.rs

@@ -84,7 +84,7 @@ impl<'b> CodeGenerator for ArtiqCodeGenerator<'b> {
                 .try_as_basic_value()
                 .left()
                 .unwrap();
-            let end_store = self.gen_store_target(ctx, &end)?;
+            let end_store = self.gen_store_target(ctx, &end, Some("end_store.addr"))?;
             ctx.builder.build_store(end_store, max);
         }
         if let Some(start) = self.start.clone() {
@@ -140,7 +140,7 @@ impl<'b> CodeGenerator for ArtiqCodeGenerator<'b> {
                                     node: ExprKind::Name { id: start, ctx: name_ctx.clone() },
                                     custom: Some(ctx.primitives.int64),
                                 };
-                                let start = self.gen_store_target(ctx, &start_expr)?;
+                                let start = self.gen_store_target(ctx, &start_expr, Some("start.addr"))?;
                                 ctx.builder.build_store(start, now);
                                 Ok(Some(start_expr)) as Result<_, String>
                             },
@@ -153,7 +153,7 @@ impl<'b> CodeGenerator for ArtiqCodeGenerator<'b> {
                             node: ExprKind::Name { id: end, ctx: name_ctx.clone() },
                             custom: Some(ctx.primitives.int64),
                         };
-                        let end = self.gen_store_target(ctx, &end_expr)?;
+                        let end = self.gen_store_target(ctx, &end_expr, Some("end.addr"))?;
                         ctx.builder.build_store(end, now);
                         self.end = Some(end_expr);
                         self.name_counter += 1;
@@ -204,7 +204,7 @@ impl<'b> CodeGenerator for ArtiqCodeGenerator<'b> {
                                 .try_as_basic_value()
                                 .left()
                                 .unwrap();
-                            let outer_end = self.gen_store_target(ctx, old_end)?;
+                            let outer_end = self.gen_store_target(ctx, old_end, Some("outer_end.addr"))?;
                             ctx.builder.build_store(outer_end, max);
                         }
                         self.start = old_start;

nac3core/src/codegen/expr.rs

@@ -810,7 +810,7 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
         let zero_size_t = size_t.const_zero();
         let zero_32 = int32.const_zero();
 
-        let index = generator.gen_var_alloc(ctx, size_t.into())?;
+        let index = generator.gen_var_alloc(ctx, size_t.into(), Some("index.addr"))?;
         ctx.builder.build_store(index, zero_size_t);
 
         let elem_ty = ctx.get_llvm_type(generator, elt.custom.unwrap());
@@ -853,7 +853,7 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
             list_content =
                 ctx.build_gep_and_load(list, &[zero_size_t, zero_32]).into_pointer_value();
 
-            let i = generator.gen_store_target(ctx, target)?;
+            let i = generator.gen_store_target(ctx, target, Some("i.addr"))?;
             ctx.builder.build_store(i, ctx.builder.build_int_sub(start, step, "start_init"));
             ctx.builder.build_unconditional_branch(test_bb);
             ctx.builder.position_at_end(test_bb);
@@ -888,7 +888,7 @@ pub fn gen_comprehension<'ctx, 'a, G: CodeGenerator>(
             list = allocate_list(generator, ctx, elem_ty, length);
             list_content =
                 ctx.build_gep_and_load(list, &[zero_size_t, zero_32]).into_pointer_value();
-            let counter = generator.gen_var_alloc(ctx, size_t.into())?;
+            let counter = generator.gen_var_alloc(ctx, size_t.into(), Some("counter.addr"))?;
             // counter = -1
             ctx.builder.build_store(counter, size_t.const_int(u64::max_value(), true));
             ctx.builder.build_unconditional_branch(test_bb);

nac3core/src/codegen/generator.rs

@@ -87,8 +87,9 @@ pub trait CodeGenerator {
         &mut self,
         ctx: &mut CodeGenContext<'ctx, 'a>,
         ty: BasicTypeEnum<'ctx>,
+        name: Option<&str>,
     ) -> Result<PointerValue<'ctx>, String> {
-        gen_var(ctx, ty)
+        gen_var(ctx, ty, name)
     }
 
     /// Return a pointer pointing to the target of the expression.
@@ -96,11 +97,12 @@ pub trait CodeGenerator {
         &mut self,
         ctx: &mut CodeGenContext<'ctx, 'a>,
         pattern: &Expr<Option<Type>>,
+        name: Option<&str>,
     ) -> Result<PointerValue<'ctx>, String>
     where
         Self: Sized,
     {
-        gen_store_target(self, ctx, pattern)
+        gen_store_target(self, ctx, pattern, name)
     }
 
     /// Generate code for an assignment expression.

nac3core/src/codegen/stmt.rs

@@ -24,12 +24,13 @@ use std::convert::TryFrom;
 pub fn gen_var<'ctx, 'a>(
     ctx: &mut CodeGenContext<'ctx, 'a>,
     ty: BasicTypeEnum<'ctx>,
+    name: Option<&str>,
 ) -> Result<PointerValue<'ctx>, String> {
     // put the alloca in init block
     let current = ctx.builder.get_insert_block().unwrap();
     // position before the last branching instruction...
     ctx.builder.position_before(&ctx.init_bb.get_last_instruction().unwrap());
-    let ptr = ctx.builder.build_alloca(ty, "tmp");
+    let ptr = ctx.builder.build_alloca(ty, name.unwrap_or(""));
     ctx.builder.position_at_end(current);
     Ok(ptr)
 }
@@ -38,6 +39,7 @@ pub fn gen_store_target<'ctx, 'a, G: CodeGenerator>(
     generator: &mut G,
     ctx: &mut CodeGenContext<'ctx, 'a>,
     pattern: &Expr<Option<Type>>,
+    name: Option<&str>,
 ) -> Result<PointerValue<'ctx>, String> {
     // very similar to gen_expr, but we don't do an extra load at the end
     // and we flatten nested tuples
@@ -45,7 +47,7 @@ pub fn gen_store_target<'ctx, 'a, G: CodeGenerator>(
         ExprKind::Name { id, .. } => match ctx.var_assignment.get(id) {
             None => {
                 let ptr_ty = ctx.get_llvm_type(generator, pattern.custom.unwrap());
-                let ptr = generator.gen_var_alloc(ctx, ptr_ty)?;
+                let ptr = generator.gen_var_alloc(ctx, ptr_ty, name)?;
                 ctx.var_assignment.insert(*id, (ptr, None, 0));
                 ptr
             }
@@ -74,7 +76,7 @@ pub fn gen_store_target<'ctx, 'a, G: CodeGenerator>(
                         ctx.ctx.i32_type().const_zero(),
                         ctx.ctx.i32_type().const_int(index as u64, false),
                     ],
-                    "attr",
+                    name.unwrap_or(""),
                 )
             }
         }
@@ -135,7 +137,7 @@ pub fn gen_store_target<'ctx, 'a, G: CodeGenerator>(
                 let arr_ptr = ctx
                     .build_gep_and_load(v, &[i32_type.const_zero(), i32_type.const_zero()])
                     .into_pointer_value();
-                ctx.builder.build_gep(arr_ptr, &[index], "loadarrgep")
+                ctx.builder.build_gep(arr_ptr, &[index], name.unwrap_or(""))
             }
         }
         _ => unreachable!(),
@@ -191,7 +193,7 @@ pub fn gen_assign<'ctx, 'a, G: CodeGenerator>(
             }
         }
         _ => {
-            let ptr = generator.gen_store_target(ctx, target)?;
+            let ptr = generator.gen_store_target(ctx, target, Some("target.addr"))?;
             if let ExprKind::Name { id, .. } = &target.node {
                 let (_, static_value, counter) = ctx.var_assignment.get_mut(id).unwrap();
                 *counter += 1;
@@ -237,8 +239,8 @@ pub fn gen_for<'ctx, 'a, G: CodeGenerator>(
         if ctx.unifier.unioned(iter.custom.unwrap(), ctx.primitives.range) {
             // setup
             let iter_val = iter_val.into_pointer_value();
-            let i = generator.gen_var_alloc(ctx, int32.into())?;
-            let user_i = generator.gen_store_target(ctx, target)?;
+            let i = generator.gen_var_alloc(ctx, int32.into(), Some("for.i.addr"))?;
+            let user_i = generator.gen_store_target(ctx, target, Some("for.user_i.addr"))?;
             let (start, end, step) = destructure_range(ctx, iter_val);
             ctx.builder.build_store(i, ctx.builder.build_int_sub(start, step, "start_init"));
             ctx.builder.build_unconditional_branch(test_bb);
@@ -270,7 +272,7 @@ pub fn gen_for<'ctx, 'a, G: CodeGenerator>(
             );
             ctx.builder.position_at_end(body_bb);
         } else {
-            let counter = generator.gen_var_alloc(ctx, size_t.into())?;
+            let counter = generator.gen_var_alloc(ctx, size_t.into(), Some("for.counter.addr"))?;
             // counter = -1
             ctx.builder.build_store(counter, size_t.const_int(u64::max_value(), true));
             let len = ctx
@@ -655,7 +657,7 @@ pub fn gen_try<'ctx, 'a, G: CodeGenerator>(
         let mut final_data = None;
         let has_cleanup = !finalbody.is_empty();
         if has_cleanup {
-            let final_state = generator.gen_var_alloc(ctx, ptr_type.into())?;
+            let final_state = generator.gen_var_alloc(ctx, ptr_type.into(), Some("try.final_state.addr"))?;
             final_data = Some((final_state, Vec::new(), Vec::new()));
             if let Some((continue_target, break_target)) = ctx.loop_target {
                 let break_proxy = ctx.ctx.append_basic_block(current_fun, "try.break");
@@ -821,7 +823,7 @@ pub fn gen_try<'ctx, 'a, G: CodeGenerator>(
             ctx.builder.position_at_end(handler_bb);
             if let Some(name) = name {
                 let exn_ty = ctx.get_llvm_type(generator, type_.as_ref().unwrap().custom.unwrap());
-                let exn_store = generator.gen_var_alloc(ctx, exn_ty)?;
+                let exn_store = generator.gen_var_alloc(ctx, exn_ty, Some("try.exn_store.addr"))?;
                 ctx.var_assignment.insert(*name, (exn_store, None, 0));
                 ctx.builder.build_store(exn_store, exn.as_basic_value());
             }