From 9ab14ca6a5ddb2c228cb2e23f3cab62988958337 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Thu, 14 Dec 2023 17:40:42 +0200
Subject: [PATCH 01/10] class field pointer hell

---
 self_hosted/create_llvm_ir.jou | 41 +++++++++++++++++++++++++---------
 self_hosted/llvm.jou           |  2 ++
 self_hosted/runs_wrong.txt     |  1 -
 self_hosted/typecheck.jou      |  2 ++
 self_hosted/types.jou          |  1 +
 src/codegen.c                  |  6 ++---
 6 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index dd5e7b92..21ccdc2b 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/self_hosted/create_llvm_ir.jou
@@ -65,11 +65,16 @@ def create_llvm_union_type(types: LLVMType**, ntypes: int) -> LLVMType*:
 
     return LLVMArrayType(LLVMInt64Type(), ((size_needed + 7) / 8) as int)  # ceil division
 
+
+# Pointers in classes are stored as i8*, so that a struct can contain a pointer to itself.
+def field_uses_i8_ptr_hack(field: ClassField*) -> bool:
+    return field->type->kind == TypeKind::Pointer
+
+
 def class_type_to_llvm(fields: ClassField*, nfields: int) -> LLVMType*:
     elem_types: LLVMType** = malloc(nfields * sizeof elem_types[0])
     for i = 0; i < nfields; i++:
-        # Store all pointers in structs as i8*, so that a struct can contain a pointer to itself for example.
-        if fields[i].type->kind == TypeKind::Pointer:
+        if field_uses_i8_ptr_hack(&fields[i]):
             elem_types[i] = LLVMPointerType(LLVMInt8Type(), 0)
         else:
             elem_types[i] = type_to_llvm(fields[i].type)
@@ -224,6 +229,13 @@ class AstToIR:
         printf("unimplemented cast: %s --> %s\n", from->name, to->name)
         assert False
 
+    # Makes a temporary pointer, places the value there, then casts and reads the pointer.
+    def do_cast_through_pointers(self, value: LLVMValue*, to: LLVMType*) -> LLVMValue*:
+        p1 = LLVMBuildAlloca(self->builder, LLVMTypeOf(value), "cast_through_ptr_temp")
+        LLVMBuildStore(self->builder, value, p1)
+        p2 = LLVMBuildBitCast(self->builder, p1, LLVMPointerType(to, 0), "cast_through_ptr_temp")
+        return LLVMBuildLoad(self->builder, p2, "cast_through_ptr_result")
+
     def do_binop(
         self,
         op: AstExpressionKind,
@@ -390,19 +402,21 @@ class AstToIR:
             assert field != NULL
             field_pointer = LLVMBuildStructGEP2(
                 self->builder,
-                type_to_llvm(class_type), instance_pointer,
+                type_to_llvm(class_type),
+                instance_pointer,
                 field->union_id,
                 field->name,
             )
 
-            # This cast is needed for two reasons two cases:
-            #   * All pointers are i8* in structs so we can do self-referencing classes.
-            #   * This is how unions work.
-            return LLVMBuildBitCast(
-                self->builder,
-                field_pointer, LLVMPointerType(type_to_llvm(field->type),0),
-                "struct_member_cast",
-            )
+            if field_uses_i8_ptr_hack(field) or field->belongs_to_union:
+                field_pointer = LLVMBuildBitCast(
+                    self->builder,
+                    field_pointer,
+                    LLVMPointerType(type_to_llvm(field->type), 0),
+                    "class_field_ptr_cast",
+                )
+
+            return field_pointer
 
         if ast->kind == AstExpressionKind::Indexing:
             # &pointer[index] = pointer + some offset
@@ -568,6 +582,8 @@ class AstToIR:
                 field = instance_type->class_members.find_field(ast->instantiation.field_names[i])
                 assert field != NULL
                 value = self->do_expression(&ast->instantiation.field_values[i])
+                if field_uses_i8_ptr_hack(field) or field->belongs_to_union:
+                    value = self->do_cast_through_pointers(value, LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id))
                 result = LLVMBuildInsertValue(self->builder, result, value, field->union_id, "instance")
 
         elif ast->kind == AstExpressionKind::GetClassField:
@@ -584,6 +600,9 @@ class AstToIR:
             assert field != NULL
             result = LLVMBuildExtractValue(self->builder, instance, field->union_id, field->name)
 
+            if field_uses_i8_ptr_hack(field) or field->belongs_to_union:
+                result = self->do_cast_through_pointers(result, type_to_llvm(field->type))
+
         elif ast->kind == AstExpressionKind::GetVariable:
             v = get_special_constant(ast->varname)
             if v == -1:
diff --git a/self_hosted/llvm.jou b/self_hosted/llvm.jou
index 8001c04d..c4423e61 100644
--- a/self_hosted/llvm.jou
+++ b/self_hosted/llvm.jou
@@ -198,6 +198,7 @@ declare LLVMDisposeModule(M: LLVMModule*) -> None
 declare LLVMGetSourceFileName(M: LLVMModule*, Len: long*) -> byte*  # Return value not owned
 declare LLVMSetDataLayout(M: LLVMModule*, DataLayoutStr: byte*) -> None
 declare LLVMSetTarget(M: LLVMModule*, Triple: byte*) -> None
+declare LLVMDumpType(Val: LLVMType*) -> None
 declare LLVMDumpModule(M: LLVMModule*) -> None
 declare LLVMPrintModuleToString(M: LLVMModule*) -> byte*
 declare LLVMAddFunction(M: LLVMModule*, Name: byte*, FunctionTy: LLVMType*) -> LLVMValue*
@@ -212,6 +213,7 @@ declare LLVMIntType(NumBits: int) -> LLVMType*
 declare LLVMGetReturnType(FunctionTy: LLVMType*) -> LLVMType*
 declare LLVMGetParam(Fn: LLVMValue*, Index: int) -> LLVMValue*
 declare LLVMGetElementType(Ty: LLVMType*) -> LLVMType*
+declare LLVMStructGetTypeAtIndex(StructTy: LLVMType*, i: int) -> LLVMType*
 declare LLVMTypeOf(Val: LLVMValue*) -> LLVMType*
 declare LLVMConstNull(Ty: LLVMType*) -> LLVMValue*
 declare LLVMGetUndef(Ty: LLVMType*) -> LLVMValue*
diff --git a/self_hosted/runs_wrong.txt b/self_hosted/runs_wrong.txt
index 02c37c70..d6ecf9bb 100644
--- a/self_hosted/runs_wrong.txt
+++ b/self_hosted/runs_wrong.txt
@@ -4,7 +4,6 @@ tests/other_errors/missing_value_in_return.jou
 tests/other_errors/noreturn_but_return_with_value.jou
 tests/other_errors/noreturn_but_return_without_value.jou
 tests/should_succeed/compiler_cli.jou
-tests/should_succeed/linked_list.jou
 tests/should_succeed/pointer.jou
 tests/should_succeed/printf.jou
 tests/other_errors/return_void.jou
diff --git a/self_hosted/typecheck.jou b/self_hosted/typecheck.jou
index 2b9d18f5..9265f5a8 100644
--- a/self_hosted/typecheck.jou
+++ b/self_hosted/typecheck.jou
@@ -419,6 +419,7 @@ def handle_class_members_stage2(ft: FileTypes*, classdef: AstClassDef*) -> None:
                 name = member->field.name,
                 type = type_from_ast(ft, &member->field.type),
                 union_id = union_id++,
+                belongs_to_union = False,
             }
         elif member->kind == AstClassMemberKind::Union:
             uid = union_id++
@@ -428,6 +429,7 @@ def handle_class_members_stage2(ft: FileTypes*, classdef: AstClassDef*) -> None:
                     name = member->union_fields.fields[k].name,
                     type = type_from_ast(ft, &member->union_fields.fields[k].type),
                     union_id = uid,
+                    belongs_to_union = True,
                 }
         elif member->kind == AstClassMemberKind::Method:
             # Don't handle the method body yet: that is a part of stage 3, not stage 2
diff --git a/self_hosted/types.jou b/self_hosted/types.jou
index 5656fa0e..7f7158ed 100644
--- a/self_hosted/types.jou
+++ b/self_hosted/types.jou
@@ -30,6 +30,7 @@ class ClassField:
     # If multiple fields have the same union_id, they belong to the same union.
     # It means that only one of the fields can be used at a time.
     union_id: int
+    belongs_to_union: bool  # are there more fields with same union_id
 
 class ClassMembers:
     fields: ClassField*
diff --git a/src/codegen.c b/src/codegen.c
index 313b5de4..e2d75753 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -78,8 +78,8 @@ static LLVMTypeRef codegen_type(const Type *type)
 
             LLVMTypeRef *flat_elems = malloc(sizeof(flat_elems[0]) * n);  // NOLINT
             for (int i = 0; i < n; i++) {
-                // Treat all pointers inside structs as if they were void*.
-                // This allows structs to contain pointers to themselves.
+                // Treat all pointers inside classes as if they were void*.
+                // This allows classes to contain pointers to themselves.
                 if (type->data.classdata.fields.ptr[i].type->kind == TYPE_POINTER)
                     flat_elems[i] = codegen_type(voidPtrType);
                 else
@@ -323,7 +323,7 @@ static void codegen_instruction(const struct State *st, const CfInstruction *ins
 
                 LLVMValueRef val = LLVMBuildStructGEP2(st->builder, codegen_type(classtype), getop(0), f->union_id, ins->data.fieldname);
                 // This cast is needed in two cases:
-                //  * All pointers are i8* in structs so we can do self-referencing classes.
+                //  * All pointers are i8* in classes so we can do self-referencing classes.
                 //  * This is how unions work.
                 val = LLVMBuildBitCast(st->builder, val, LLVMPointerType(codegen_type(f->type),0), "struct_member_cast");
                 setdest(val);

From a58e758be1e8d8b91fe845c78e45ab6cda633666 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 01:25:47 +0200
Subject: [PATCH 02/10] pile of asserts and such

---
 self_hosted/create_llvm_ir.jou | 6 +++++-
 self_hosted/llvm.jou           | 3 +++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index 21ccdc2b..ea9349c4 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/self_hosted/create_llvm_ir.jou
@@ -85,9 +85,12 @@ def class_type_to_llvm(fields: ClassField*, nfields: int) -> LLVMType*:
         end = start + 1
         while end < nfields and fields[start].union_id == fields[end].union_id:
             end++
+        assert fields[start].union_id == combined_len
         elem_types[combined_len++] = create_llvm_union_type(&elem_types[start], end-start)
 
     result = LLVMStructType(elem_types, combined_len, False as int)
+    for i = 0; i < combined_len; i++:
+        assert LLVMStructGetTypeAtIndex(result, i) == elem_types[i]
     free(elem_types)
     return result
 
@@ -234,7 +237,7 @@ class AstToIR:
         p1 = LLVMBuildAlloca(self->builder, LLVMTypeOf(value), "cast_through_ptr_temp")
         LLVMBuildStore(self->builder, value, p1)
         p2 = LLVMBuildBitCast(self->builder, p1, LLVMPointerType(to, 0), "cast_through_ptr_temp")
-        return LLVMBuildLoad(self->builder, p2, "cast_through_ptr_result")
+        return LLVMBuildLoad2(self->builder, to, p2, "cast_through_ptr_result")
 
     def do_binop(
         self,
@@ -584,6 +587,7 @@ class AstToIR:
                 value = self->do_expression(&ast->instantiation.field_values[i])
                 if field_uses_i8_ptr_hack(field) or field->belongs_to_union:
                     value = self->do_cast_through_pointers(value, LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id))
+                    assert LLVMTypeOf(value) == LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id)
                 result = LLVMBuildInsertValue(self->builder, result, value, field->union_id, "instance")
 
         elif ast->kind == AstExpressionKind::GetClassField:
diff --git a/self_hosted/llvm.jou b/self_hosted/llvm.jou
index c4423e61..abd7b1ee 100644
--- a/self_hosted/llvm.jou
+++ b/self_hosted/llvm.jou
@@ -215,6 +215,7 @@ declare LLVMGetParam(Fn: LLVMValue*, Index: int) -> LLVMValue*
 declare LLVMGetElementType(Ty: LLVMType*) -> LLVMType*
 declare LLVMStructGetTypeAtIndex(StructTy: LLVMType*, i: int) -> LLVMType*
 declare LLVMTypeOf(Val: LLVMValue*) -> LLVMType*
+declare LLVMAlignOf(Ty: LLVMType*) -> LLVMValue*
 declare LLVMConstNull(Ty: LLVMType*) -> LLVMValue*
 declare LLVMGetUndef(Ty: LLVMType*) -> LLVMValue*
 declare LLVMConstInt(IntTy: LLVMType*, N: long, SignExtend: int) -> LLVMValue*
@@ -252,8 +253,10 @@ declare LLVMBuildXor(Builder: LLVMBuilder*, LHS: LLVMValue*, RHS: LLVMValue*, Na
 declare LLVMBuildNeg(Builder: LLVMBuilder*, V: LLVMValue*, Name: byte*) -> LLVMValue*
 declare LLVMBuildFNeg(Builder: LLVMBuilder*, V: LLVMValue*, Name: byte*) -> LLVMValue*
 declare LLVMBuildMemSet(Builder: LLVMBuilder*, Ptr: LLVMValue*, Val: LLVMValue*, Len: LLVMValue*, Align: int) -> LLVMValue*
+declare LLVMBuildMemCpy(Builder: LLVMBuilder*, Dst: LLVMValue*, DstAlign: int, Src: LLVMValue*, SrcAlign: int, Size: LLVMValue*) -> LLVMValue*
 declare LLVMBuildAlloca(Builder: LLVMBuilder*, Ty: LLVMType*, Name: byte*) -> LLVMValue*
 declare LLVMBuildLoad(Builder: LLVMBuilder*, PointerVal: LLVMValue*, Name: byte*) -> LLVMValue*
+declare LLVMBuildLoad2(Builder: LLVMBuilder*, Ty: LLVMType*, PointerVal: LLVMValue*, Name: byte*) -> LLVMValue*
 declare LLVMBuildStore(Builder: LLVMBuilder*, Val: LLVMValue*, Ptr: LLVMValue*) -> LLVMValue*
 declare LLVMBuildGEP(Builder: LLVMBuilder*, Pointer: LLVMValue*, Indices: LLVMValue**, NumIndices: int, Name: byte*) -> LLVMValue*
 declare LLVMBuildStructGEP2(Builder: LLVMBuilder*, Ty: LLVMType*, Pointer: LLVMValue*, Idx: int, Name: byte*) -> LLVMValue*

From e78c8fe57910e2c117929a0ea033c5dbc6f30597 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 01:28:41 +0200
Subject: [PATCH 03/10] TEMPORARY debugs

---
 .github/workflows/autofix.yml |  22 -----
 .github/workflows/linux.yml   |  80 ----------------
 .github/workflows/macos.yml   |  42 --------
 .github/workflows/release.yml |  89 -----------------
 .github/workflows/windows.yml | 176 +---------------------------------
 5 files changed, 4 insertions(+), 405 deletions(-)
 delete mode 100644 .github/workflows/autofix.yml
 delete mode 100644 .github/workflows/linux.yml
 delete mode 100644 .github/workflows/macos.yml
 delete mode 100644 .github/workflows/release.yml

diff --git a/.github/workflows/autofix.yml b/.github/workflows/autofix.yml
deleted file mode 100644
index c9b34895..00000000
--- a/.github/workflows/autofix.yml
+++ /dev/null
@@ -1,22 +0,0 @@
-on:
-  push:
-    branches:
-      - main
-  pull_request_target:
-
-jobs:
-  fix-line-endings:
-    runs-on: ubuntu-latest
-    steps:
-      # git-auto-commit-action is a bit tricky to use, see its README
-      - uses: actions/checkout@v3
-        with:
-          repository: ${{ github.event.pull_request.head.repo.full_name }}
-          ref: ${{ github.head_ref }}
-      - run: sudo apt install -y dos2unix
-      - run: dos2unix $(git ls-files | grep -vx tests/should_succeed/crlf.jou)
-      - run: unix2dos tests/should_succeed/crlf.jou
-      - uses: stefanzweifel/git-auto-commit-action@v4
-        with:
-          commit_message: "Change files to use LF line endings"
-
diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
deleted file mode 100644
index 1d08b5e9..00000000
--- a/.github/workflows/linux.yml
+++ /dev/null
@@ -1,80 +0,0 @@
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-
-jobs:
-  shellcheck:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - run: shellcheck --color=always --shell=bash --exclude=SC2086,SC2059,SC2046,SC2235,SC2002,SC2206,SC2068,SC2207,SC2013 *.sh activate
-
-  test:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        llvm-version: [11, 13]
-        # Testing all levels because there was a bug that only happened with -O1. (#224)
-        opt-level: ['-O0', '-O1', '-O2', '-O3']
-    steps:
-      - uses: actions/checkout@v3
-      - run: sudo apt update
-      - run: sudo apt install -y llvm-${{ matrix.llvm-version }}-dev clang-${{ matrix.llvm-version }} make valgrind
-      - run: LLVM_CONFIG=llvm-config-${{ matrix.llvm-version }} make
-      - run: ./runtests.sh --verbose --jou-flags "${{ matrix.opt-level }}"
-      - run: ./runtests.sh --verbose --jou-flags "${{ matrix.opt-level }} --verbose"
-      # Valgrinding is slow, but many files affect valgrind results.
-      # We skip it when all changes are to .md files (docs, README etc)
-      - name: Figure out if we need to run tests with valgrind
-        id: check-need-valgrind
-        run: |
-          git fetch https://github.com/Akuli/jou main
-          # Find modified non-markdown files. If there are any, set doit=yes.
-          if git diff --name-only FETCH_HEAD HEAD | grep -vE '\.md$'; then
-            echo doit=yes >> $GITHUB_OUTPUT
-          else
-            echo doit=no >> $GITHUB_OUTPUT
-          fi
-      - if: ${{ steps.check-need-valgrind.outputs.doit == 'yes' }}
-        run: ./runtests.sh --verbose --valgrind --jou-flags "${{ matrix.opt-level }}"
-      # valgrind+verbose isn't meaningful: test script would ignore valgrind output
-      - run: make clean
-      - name: Check that "make clean" deleted all files not committed to Git
-        run: |
-          if [ "$(git status --porcelain --ignored)" != "" ]; then
-            git status --ignored
-            exit 1
-          fi
-
-  doctest:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        llvm-version: [11, 13]
-    steps:
-      - uses: actions/checkout@v3
-      - run: sudo apt update
-      - run: sudo apt install -y llvm-${{ matrix.llvm-version }}-dev clang-${{ matrix.llvm-version }} make
-      - run: LLVM_CONFIG=llvm-config-${{ matrix.llvm-version }} make
-      - run: ./doctest.sh
-
-  compare-compilers:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - run: sudo apt update
-      - run: sudo apt install -y llvm-13-dev clang-13 make valgrind
-      - run: LLVM_CONFIG=llvm-config-13 make
-      - run: ./compare_compilers.sh
-
-  editorconfig-checker:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      # Hard-coded commit, because the latest changes aren't tagged.
-      - uses: editorconfig-checker/action-editorconfig-checker@d4fca16fc71adef10fbe101903b654449fa9570c
-        with:
-          version: 2.7.0
-      - run: editorconfig-checker
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
deleted file mode 100644
index 72bad46c..00000000
--- a/.github/workflows/macos.yml
+++ /dev/null
@@ -1,42 +0,0 @@
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-
-jobs:
-  test:
-    runs-on: macos-latest
-    strategy:
-      matrix:
-        # Testing all levels because there was a bug that only happened with -O1. (#224)
-        opt-level: ['-O0', '-O1', '-O2', '-O3']
-    steps:
-      - uses: actions/checkout@v3
-      - run: brew install bash diffutils llvm@13
-      - run: make
-      - run: ./runtests.sh --verbose --jou-flags "${{ matrix.opt-level }}"
-      - run: ./runtests.sh --verbose --jou-flags "${{ matrix.opt-level }} --verbose"
-      - run: make clean
-      - name: Check that "make clean" deleted all files not committed to Git
-        shell: bash
-        run: |
-          if [ "$(git status --porcelain --ignored)" != "" ]; then
-            git status --ignored
-            exit 1
-          fi
-
-  doctest:
-    runs-on: macos-latest
-    steps:
-      - uses: actions/checkout@v3
-      - run: brew install bash diffutils llvm@13
-      - run: make
-      - run: ./doctest.sh
-
-  compare-compilers:
-    runs-on: macos-latest
-    steps:
-      - uses: actions/checkout@v3
-      - run: brew install bash diffutils llvm@13
-      - run: ./compare_compilers.sh
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
deleted file mode 100644
index d46dea47..00000000
--- a/.github/workflows/release.yml
+++ /dev/null
@@ -1,89 +0,0 @@
-#
-#
-#
-# *** If you edit this file, make sure that CONTRIBUTING.md stays up to date.
-#
-#
-#
-on:
-  schedule:
-    - cron: '0 4 * * *'
-  workflow_dispatch:  # Can also be triggered manually from github UI
-
-jobs:
-  release:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - run: git fetch --tags
-      - id: tagname
-        run: |
-          if git tag -l --contains HEAD | grep .; then
-            # Commit already tagged
-            echo datetag= >> $GITHUB_OUTPUT
-          else
-            echo datetag=$(date +'%Y-%m-%d-%H00') > $GITHUB_OUTPUT
-          fi
-      - if: ${{ steps.tagname.outputs.datetag != '' }}
-        name: Download latest GitHub actions build results
-        uses: actions/github-script@v6
-        with:
-          github-token: ${{secrets.GITHUB_TOKEN}}
-          script: |
-            const fs = require('fs');
-
-            // Based on:  https://github.com/python/typeshed/blob/82fa8473ffddc57a53b4dbcb1063aa2e66352ca9/.github/workflows/mypy_primer_comment.yml
-            const allRuns = (
-              await github.rest.actions.listWorkflowRunsForRepo({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                branch: 'main',
-              })
-            ).data.workflow_runs;
-            console.log(`Found ${allRuns.length} runs`);
-            console.log(allRuns.map(r => r.name));
-            const run = allRuns
-              .filter(r => r.name === '.github/workflows/windows.yml')
-              .sort((a, b) => (+new Date(b.run_started_at)) - (+new Date(a.run_started_at)))[0];
-
-            const allArtifacts = (
-              await github.rest.actions.listWorkflowRunArtifacts({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                run_id: run.id,
-              })
-            ).data.artifacts;
-            console.log(`Found ${allArtifacts.length} artifacts`);
-            console.log(allArtifacts.map(a => a.name));
-            const artifact = allArtifacts.filter(a => a.name === 'windows-zip')[0];
-
-            const zip = await github.rest.actions.downloadArtifact({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                artifact_id: artifact.id,
-                archive_format: 'zip',
-            });
-
-            // https://stackoverflow.com/a/46779188
-            fs.writeFileSync("nested-zip-file.zip", Buffer.from(zip.data));
-
-      # We get a zip file inside a zip file:
-      #   * Inner zip file: The build creates a releasing-ready zip file. This is
-      #     good because you can test the zip file before Jou is released.
-      #   * Outer zip file: It is possible to include multiple files to the same
-      #     GitHub Actions artifact, and downloadArtifact() gives a zip of all
-      #     files that the artifact consists of.
-      - if: ${{ steps.tagname.outputs.datetag != '' }}
-        run: unzip nested-zip-file.zip
-
-      - if: ${{ steps.tagname.outputs.datetag != '' }}
-        run: mv jou.zip jou_windows_64bit_${{ steps.tagname.outputs.datetag }}.zip
-
-      - if: ${{ steps.tagname.outputs.datetag != '' }}
-        name: Create release
-        uses: ncipollo/release-action@v1
-        with:
-          commit: main
-          tag: ${{ steps.tagname.outputs.datetag }}
-          artifacts: jou_windows_64bit_${{ steps.tagname.outputs.datetag }}.zip
-          skipIfReleaseExists: true
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 1f959b83..0252eca9 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -12,183 +12,15 @@ on:
   pull_request:
 
 jobs:
-  # I created a zip file that contains mingw64, but with some large files deleted.
-  # These large files are most of the time unnecessary for developing Jou.
-  # People with slow internet need the smaller zip file.
-  #
-  # This check fails if the zip file contains anything else than what's in the original/full zip file.
-  # It serves two purposes:
-  #   * People can trust the random zip file I have created locally on my system and committed.
-  #   * I can be sure that I didn't accidentally include something unnecessary or do something else dumb.
-  check-small-mingw64:
-    runs-on: ubuntu-latest
-    steps:
-      # Same URLs as in windows_setup.sh
-      - name: Download the small mingw64
-        run: curl -L -o mingw64-small.zip https://akuli.github.io/mingw64-small.zip
-      - name: Download the full mingw64
-        run: curl -L -o mingw64.zip https://github.com/brechtsanders/winlibs_mingw/releases/download/12.1.0-14.0.6-10.0.0-msvcrt-r3/winlibs-x86_64-posix-seh-gcc-12.1.0-llvm-14.0.6-mingw-w64msvcrt-10.0.0-r3.zip
-      # Same SHA hashes as in windows_setup.sh
-      - name: Veriy the small mingw64
-        run: |
-          if [ "$(sha256sum mingw64-small.zip | cut -d' ' -f1)" != "4d858bd22f084ae362ee6a22a52c2c5b5281d996f96693984a31336873b92686" ]; then
-            echo "verifying failed"
-            exit 1
-          fi
-      - name: Veriy the full mingw64
-        run: |
-          if [ "$(sha256sum mingw64.zip | cut -d' ' -f1)" != "9ffef7f7a8dab893bd248085fa81a5a37ed6f775ae220ef673bea8806677836d" ]; then
-            echo "verifying failed"
-            exit 1
-          fi
-      - name: Make sure that all file paths start with mingw64
-        run: |
-          zipinfo -1 mingw64.zip > output.txt
-          zipinfo -1 mingw64-small.zip >> output.txt
-          cat output.txt
-          if [ "$(cut -d/ -f1 output.txt | uniq)" != "mingw64" ]; then
-            exit 1
-          fi
-      - run: ls -lh mingw64*.zip
-      - name: Extract mingw64.zip
-        run: mkdir full && cd full && unzip ../mingw64.zip
-      - name: Extract mingw64-small.zip
-        run: mkdir small && cd small && unzip ../mingw64-small.zip
-      - name: Compare files
-        run: |
-          # diff exits with status 1 because the folders differ.
-          # Put errors to output.txt as well, so that we notice if something goes wrong.
-          (diff -r full small || true) &> output.txt
-          cat output.txt
-          if [ "$(cut -d/ -f1 output.txt | uniq)" != "Only in full" ]; then
-            exit 1
-          fi
-
-  build-zip:
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@v3
-      # TODO: figure out why --small doesn't work here
-      - run: source activate && ./windows_setup.sh
-        shell: bash
-      - run: source activate && mingw32-make
-        shell: bash
-      # We don't need to copy all of mingw64. We only need the GNU linker.
-      # The less we copy, the smaller the resulting zip becomes.
-      #
-      # gcc is needed only to run the linker. It would be possible to invoke ld.exe
-      # directly, but the command-line it wants is a bit complicated and it's just
-      # easier to let a C compiler figure it out. I also tried using clang instead
-      # of gcc, but it depends on many LLVM DLLs and the zip file became huge.
-      - name: Copy the linker from mingw64 to jou/mingw64
-        shell: bash
-        run: |
-          # Executables are copied without their DLLs (added later)
-          # Names of .a files figured out by deleting them all and looking at error message.
-          # CRT (C RunTime) files are needed because the linker implicitly adds them to every executable.
-          for file in \
-              mingw64/version_info.txt \
-              $(find mingw64 -name 'crt*.o') \
-              mingw64/bin/gcc.exe \
-              mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/libgcc.a \
-              mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/libgcc_eh.a \
-              mingw64/libexec/gcc/x86_64-w64-mingw32/12.1.0/liblto_plugin.dll \
-              mingw64/x86_64-w64-mingw32/bin/ld.exe \
-              mingw64/x86_64-w64-mingw32/lib/libadvapi32.a \
-              mingw64/x86_64-w64-mingw32/lib/libkernel32.a \
-              mingw64/x86_64-w64-mingw32/lib/libm.a \
-              mingw64/x86_64-w64-mingw32/lib/libmingw32.a \
-              mingw64/x86_64-w64-mingw32/lib/libmingwex.a \
-              mingw64/x86_64-w64-mingw32/lib/libmoldname.a \
-              mingw64/x86_64-w64-mingw32/lib/libmsvcrt.a \
-              mingw64/x86_64-w64-mingw32/lib/libpthread.a \
-              mingw64/x86_64-w64-mingw32/lib/libshell32.a \
-              mingw64/x86_64-w64-mingw32/lib/libuser32.a
-          do
-            mkdir -vp jou/$(dirname $file)
-            cp -v $file jou/$file
-          done
-      - name: Copy more files to jou/
-        # Please keep this list of files in sync with update.ps1
-        run: cp -rv stdlib doc examples LICENSE jou.exe update.ps1 jou
-        shell: bash
-      - name: Copy missing DLL files to jou/
-        shell: bash
-        run: |
-          function copy_dlls() {
-            local from=$1
-            local to=$2
-            local queue=($to/*.exe)
-            while [ ${#queue[@]} != 0 ]; do
-              local args=(${queue[@]})
-              queue=()
-              for dll in $(mingw64/bin/objdump -p ${args[@]} | grep 'DLL Name:' | cut -d: -f2 | sort -u); do
-                if [ -f $from/$dll ] && ! [ -f $to/$dll ]; then
-                  cp -v $from/$dll $to/
-                  queue+=($to/$dll)
-                fi
-              done
-            done
-          }
-          copy_dlls mingw64/bin jou
-          copy_dlls mingw64/bin jou/mingw64/bin
-          copy_dlls mingw64/x86_64-w64-mingw32/bin jou/mingw64/x86_64-w64-mingw32/bin
-      - name: Convert text files to Windows-style CRLF line endings
-        run: mingw64/bin/unix2dos $(find jou -name '*.jou') $(find jou -name '*.md') jou/LICENSE
-        shell: bash
-      - run: Compress-Archive -Path jou -DestinationPath jou.zip
-      - name: Display size of jou.zip
-        run: ls -lh jou.zip
-        shell: bash
-      - uses: actions/upload-artifact@v3
-        with:
-          name: windows-zip
-          path: jou.zip
-
-  test:
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          # Add a space in the folder name to trigger bugs like #165
-          path: "test dir"
-      - run: cd "test dir" && ./windows_setup.sh --small
-        shell: bash
-      - run: cd "test dir" && source activate && ./runtests.sh --verbose
-        shell: bash
-
-  doctest:
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@v3
-      - run: ./windows_setup.sh --small
-        shell: bash
-      - run: source activate && ./doctest.sh
-        shell: bash
-
-  test-zip:
-    needs: build-zip
-    runs-on: windows-latest
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          path: repo
-      - uses: actions/download-artifact@v3
-        with:
-          name: windows-zip
-      - run: unzip jou.zip
-      - run: cp -r repo/tests repo/runtests.sh jou
-        shell: bash
-      - run: cd jou && ./jou.exe --verbose examples/hello.jou
-        shell: bash
-      - run: cd jou && ./runtests.sh --dont-run-make --verbose
-        shell: bash
-
   compare-compilers:
     runs-on: windows-latest
     steps:
       - uses: actions/checkout@v3
       - run: source activate && ./windows_setup.sh --small
         shell: bash
+      - run: source activate && mingw32-make self_hosted_compiler.exe
+        shell: bash
+      - run: source activate && ./self_hosted_compiler.exe -vv tests/should_succeed/union.jou
+        shell: bash
       - run: source activate && ./compare_compilers.sh
         shell: bash

From 9b53f1322506af4f717bd2178af952a825074835 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 01:38:23 +0200
Subject: [PATCH 04/10] is it even called?

---
 self_hosted/create_llvm_ir.jou | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index ea9349c4..97c996d8 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/self_hosted/create_llvm_ir.jou
@@ -234,6 +234,9 @@ class AstToIR:
 
     # Makes a temporary pointer, places the value there, then casts and reads the pointer.
     def do_cast_through_pointers(self, value: LLVMValue*, to: LLVMType*) -> LLVMValue*:
+        printf("Cast through pointers!!!!!\n")
+        fflush(stdout)
+
         p1 = LLVMBuildAlloca(self->builder, LLVMTypeOf(value), "cast_through_ptr_temp")
         LLVMBuildStore(self->builder, value, p1)
         p2 = LLVMBuildBitCast(self->builder, p1, LLVMPointerType(to, 0), "cast_through_ptr_temp")

From 1750b4986ed10769b3be310bb3c57c9bf1b92867 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 01:45:40 +0200
Subject: [PATCH 05/10] debug print

---
 self_hosted/typecheck.jou | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/self_hosted/typecheck.jou b/self_hosted/typecheck.jou
index 9265f5a8..1a1cad0c 100644
--- a/self_hosted/typecheck.jou
+++ b/self_hosted/typecheck.jou
@@ -424,6 +424,8 @@ def handle_class_members_stage2(ft: FileTypes*, classdef: AstClassDef*) -> None:
         elif member->kind == AstClassMemberKind::Union:
             uid = union_id++
             for k = 0; k < member->union_fields.nfields; k++:
+                printf("typecheck: set belongs_to_union = True\n")
+                fflush(stdout)
                 type->class_members.fields = realloc(type->class_members.fields, (type->class_members.nfields + 1) * sizeof type->class_members.fields[0])
                 type->class_members.fields[type->class_members.nfields++] = ClassField{
                     name = member->union_fields.fields[k].name,

From 1e65d71b6b46b57458a41df6efbbc6078c7276d3 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 01:56:19 +0200
Subject: [PATCH 06/10] more debug print

---
 self_hosted/create_llvm_ir.jou | 7 +++++++
 self_hosted/typecheck.jou      | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index 97c996d8..3548537b 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/self_hosted/create_llvm_ir.jou
@@ -588,6 +588,13 @@ class AstToIR:
                 field = instance_type->class_members.find_field(ast->instantiation.field_names[i])
                 assert field != NULL
                 value = self->do_expression(&ast->instantiation.field_values[i])
+                printf("create_llvm_ir: (type=%s) get belongs_to_union = ", instance_type->name)
+                if field->belongs_to_union:
+                    printf("True")
+                else:
+                    printf("False")
+                printf(" for field '%s'\n", field->name)
+                fflush(stdout)
                 if field_uses_i8_ptr_hack(field) or field->belongs_to_union:
                     value = self->do_cast_through_pointers(value, LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id))
                     assert LLVMTypeOf(value) == LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id)
diff --git a/self_hosted/typecheck.jou b/self_hosted/typecheck.jou
index 1a1cad0c..86cef95f 100644
--- a/self_hosted/typecheck.jou
+++ b/self_hosted/typecheck.jou
@@ -424,7 +424,7 @@ def handle_class_members_stage2(ft: FileTypes*, classdef: AstClassDef*) -> None:
         elif member->kind == AstClassMemberKind::Union:
             uid = union_id++
             for k = 0; k < member->union_fields.nfields; k++:
-                printf("typecheck: set belongs_to_union = True\n")
+                printf("typecheck: (type=%s) set belongs_to_union = True for field '%s'\n", type->name, member->union_fields.fields[k].name)
                 fflush(stdout)
                 type->class_members.fields = realloc(type->class_members.fields, (type->class_members.nfields + 1) * sizeof type->class_members.fields[0])
                 type->class_members.fields[type->class_members.nfields++] = ClassField{

From 82d953a3b3e1d1a162ba71ee0f4e8879fba91eac Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 02:01:28 +0200
Subject: [PATCH 07/10] more debug

---
 self_hosted/create_llvm_ir.jou | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index 3548537b..0416fb6c 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/self_hosted/create_llvm_ir.jou
@@ -596,6 +596,8 @@ class AstToIR:
                 printf(" for field '%s'\n", field->name)
                 fflush(stdout)
                 if field_uses_i8_ptr_hack(field) or field->belongs_to_union:
+                    printf("IF STATEMENT\n")
+                    fflush(stdout)
                     value = self->do_cast_through_pointers(value, LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id))
                     assert LLVMTypeOf(value) == LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id)
                 result = LLVMBuildInsertValue(self->builder, result, value, field->union_id, "instance")

From cf71c001a9c41d41f3db6a2a22d4c679adbdc9a4 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 02:01:53 +0200
Subject: [PATCH 08/10] even more debug

---
 self_hosted/create_llvm_ir.jou | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index 0416fb6c..a0c26196 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/self_hosted/create_llvm_ir.jou
@@ -600,6 +600,9 @@ class AstToIR:
                     fflush(stdout)
                     value = self->do_cast_through_pointers(value, LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id))
                     assert LLVMTypeOf(value) == LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id)
+                else:
+                    printf("ELSE STATEMENT\n")
+                    fflush(stdout)
                 result = LLVMBuildInsertValue(self->builder, result, value, field->union_id, "instance")
 
         elif ast->kind == AstExpressionKind::GetClassField:

From 4f9f9dfeb294f345cc596ca4b2f8d7cc1a9797d0 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 02:04:46 +0200
Subject: [PATCH 09/10] more debug

---
 self_hosted/create_llvm_ir.jou | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index a0c26196..7f3df9b2 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/self_hosted/create_llvm_ir.jou
@@ -595,7 +595,12 @@ class AstToIR:
                     printf("False")
                 printf(" for field '%s'\n", field->name)
                 fflush(stdout)
-                if field_uses_i8_ptr_hack(field) or field->belongs_to_union:
+                a = field_uses_i8_ptr_hack(field)
+                b = field->belongs_to_union
+                c = a or b
+                printf("abc = %d%d%d\n", a as int, b as int, c as int)
+                fflush(stdout)
+                if c:
                     printf("IF STATEMENT\n")
                     fflush(stdout)
                     value = self->do_cast_through_pointers(value, LLVMStructGetTypeAtIndex(type_to_llvm(instance_type), field->union_id))

From 5288a464ae215daea8a1d29449df86466ee364c2 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 17 Dec 2023 02:10:35 +0200
Subject: [PATCH 10/10] disable optimizations?

---
 Makefile.windows | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile.windows b/Makefile.windows
index c6c8331a..aea9be2d 100644
--- a/Makefile.windows
+++ b/Makefile.windows
@@ -31,7 +31,7 @@ config.jou:
 	echo "    return NULL" >> config.jou
 
 self_hosted_compiler.exe: jou.exe config.jou $(wildcard self_hosted/*.jou)
-	./jou.exe -o $@ --linker-flags "$(LDFLAGS)" self_hosted/main.jou
+	./jou.exe -O0 -o $@ --linker-flags "$(LDFLAGS)" self_hosted/main.jou
 
 .PHONY: clean
 clean: