graemeg/blaise

Source: https://github.com/graemeg/blaise

= Blaise Pascal Compiler :icons: font :source-highlighter: rouge

The Pascal you love, reimagined for the modern era.

Blaise is a next-generation Object Pascal compiler built from the ground up to eliminate decades of legacy baggage. It prioritizes developer productivity, memory safety, and high-performance execution.

== ✨ The Vision

The Object Pascal ecosystem has two options: Embarcadero Delphi (proprietary, Windows-first) and Free Pascal (open source but carrying 30 years of accumulated complexity — five language modes, five string types, and thousands of include files).

This compiler takes a different approach:

• One language mode. No {$mode} switches; no legacy dialect support.
• One string type. UTF-8 reference-counted string and 0-based indexing. RawBytes for binary data.
• One memory model. Automatic reference counting applies uniformly to strings, classes, and interfaces. No manual/auto split between TObject and TInterfacedObject; [Weak] breaks cycles. Free is retained as a synonym for immediate release.
• Clean interfaces. No COM GUIDs; interface dispatch via compile-time vtable mapping.
• Reified generics. Monomorphization at compile time — no type erasure.
• Modern build system. PasBuild with project.xml; no makefiles.
• First-class debugger. OPDF is the default debug format; DWARF is not required.

See link:docs/design.adoc[docs/design.adoc] for the full architecture and implementation plan.

The result — A modern, cross-platform Object Pascal compiler targeting native code via https://c9x.me/compile/[QBE] (and eventually LLVM). Single language mode, single string type, zero-GUID interfaces, reified generics, and first-class https://github.com/graemeg/opdebugger[OPDF] debug format support.

== 🚀 Project Status

• Self-Hosting: Yes. Blaise bootstraps and recompiles itself with byte-for-byte fixpoint. FPC is no longer required — the entire toolchain runs on Blaise alone.
• Testing: 2627 tests and growing (Test-Driven Development from day one). The test suite itself compiles under Blaise.
• Backends: Currently utilising a QBE backend, with an LLVM backend in active development.

[cols=“1,3,1”, options=“header”] |=== | Phase | Goal | Status

| 1 | Bootstrap pipeline — Hello World on Linux x86_64 via PasBuild | Complete ✅

| 2 | Type system — classes, records, ARC, exceptions | Complete ✅

| 3 | Generics + zero-GUID interfaces | Complete ✅

| 4 | OPDF debug info emission | Complete ✅

| 5 | Self-hosting | Complete ✅

| 6 | Language improvements + expand RTL & StdLib + bug fixing | In-Progress

| 7 | LLVM + Windows + macOS ARM64 | Planned

| 8 | LSP + VS Code extension | Planned

| 9 | Migration analyser for FPC/Delphi codebases | Planned |===

== What Is Dropped From Classic Pascal

[cols=“1,3”, options=“header”] |=== | Feature | Reason for removal

| ShortString, AnsiString, WideString, UnicodeString | Replaced by a single UTF-8 reference-counted string type

| with statement | Source of hard-to-diagnose symbol resolution bugs; breaks static analysis

| Old-style object types | Use record (stack/value) or class (heap/reference) instead

| COM-style interface GUIDs | Interface dispatch via compile-time vtable; GUIDs are unnecessary complexity

| Multiple language modes | One dialect, maintained well, beats five dialects maintained poorly

| assign, reset, rewrite, blockread | Replaced by a stream-based I/O RTL

| TObject vs TInterfacedObject split | One unified class model under automatic reference counting; [Weak] breaks cycles |===

== 📢 Community

The core architecture is still being finalised, so the project is not yet accepting code contributions. Feedback on language design, syntax choices, and the future direction of Blaise is very welcome — please use the https://github.com/graemeg/blaise/discussions[Discussions] tab on GitHub.

== Repository Layout

This project uses PasBuild’s multi-module layout. Each subdirectory with a project.xml is an independent module; the root project.xml is the aggregator.

…. project.xml Root aggregator (packaging=pom) │ ├── compiler/ The compiler binary (packaging=application) │ ├── project.xml │ └── src/ │ ├── main/pascal/ uLexer, uParser, uAST, uCodeGenQBE, … │ └── test/pascal/ Test suite (blaise.testing, compiled by Blaise) │ ├── runtime/ Always-linked runtime (packaging=library) │ ├── project.xml │ ├── Makefile │ └── src/ │ ├── main/c/ C shims (blaise_exc.c, blaise_io.c, …) │ ├── main/pascal/ system.pas, blaise_str.pas, blaise_arc.pas, … │ └── test/pascal/ Runtime tests (punit, compiled by Blaise) │ ├── stdlib/ Standard library — opt-in via uses clause │ ├── project.xml │ └── src/ │ └── main/pascal/ sysutils.pas, classes.pas, math.pas, … │ ├── tools/ │ └── migration-analyser/ FPC/Delphi migration report tool (packaging=application) │ ├── project.xml depends on compiler module │ └── src/ │ ├── main/pascal/ │ └── test/pascal/ │ ├── vendor/qbe/ Vendored QBE backend source (pinned, built from source) └── docs/ Design documents and specifications ….

PasBuild compiles each module to its own target/ subdirectory. Build output is never committed to the repository.

== Building

=== Prerequisites

• A previously released Blaise binary (see releases/)
• https://github.com/graemeg/pasbuild[PasBuild]
• A C compiler (gcc or clang) for building the vendored QBE backend and linking
• GNU make for the runtime build

NOTE: FPC is not required. Blaise is fully self-hosting — each release binary compiles the next version. The bootstrap chain starts from the binary in releases/.

=== Bootstrap from a release

The runtime build compiles its Pascal units (blaise_str.pas, blaise_arc.pas, blaise_sys.pas) using the Blaise binary at compiler/target/blaise. On a clean checkout that binary does not exist yet, so the release binary must be passed explicitly via the BLAISE make variable.

[source,shell]

0. Build the vendored QBE backend (once-off — not needed again unless

you update vendor/qbe/)

cd vendor/qbe && make && cd ../..

1. Build the runtime using the release binary (BLAISE= avoids chicken-and-egg)

cd runtime && make BLAISE=../releases/v0.7.0/blaise && make install && cd ..

2. Compile the compiler using the latest release binary

releases/v0.7.0/blaise
–source compiler/src/main/pascal/Blaise.pas
–unit-path compiler/src/main/pascal
–unit-path runtime/src/main/pascal
–unit-path stdlib/src/main/pascal
–emit-ir > /tmp/blaise.ssa

3. Assemble and link

vendor/qbe/qbe -o /tmp/blaise.s /tmp/blaise.ssa gcc -o compiler/target/blaise /tmp/blaise.s compiler/target/blaise_rtl.a

Once compiler/target/blaise exists, subsequent RTL rebuilds (make && make install) work without the override. The QBE build in step 0 is a one-off and does not need to be repeated when rebuilding the compiler.

=== Bootstrap a development checkout

The procedure above works while the latest release binary is new enough to compile the current source. Between releases that ceases to hold: once a commit teaches the parser a new feature and a later commit uses it in the runtime/compiler, the release binary can no longer build master directly.

scripts/rolling-bootstrap.sh rebuilds the chain commit-by-commit from the last release binary up to the checked-out revision, producing a working -pre bootstrap binary. See link:scripts/BOOTSTRAP.adoc[scripts/BOOTSTRAP.adoc] for the prerequisite (placing the release binary under releases/) and usage.

=== Build via PasBuild

PasBuild can drive the full compile and test cycle using a Blaise binary:

[source,shell]

pasbuild compile -m blaise-compiler –compiler compiler/target/blaise pasbuild test -m blaise-compiler –compiler compiler/target/blaise

=== Run tests

[source,shell]

pasbuild test -m blaise-compiler –compiler compiler/target/blaise

=== Verify self-hosting fixpoint

After any compiler change, verify that the compiler reproduces itself:

[source,shell]

./scripts/fixpoint.sh

This generates stage-2 and stage-3 IR and confirms they are identical.

=== Running the compiler

Once built, the compiler binary is at compiler/target/blaise.

[source,shell]

Compile a single-file program

compiler/target/blaise –source Hello.pas –emit-ir > Hello.ssa vendor/qbe/qbe -o Hello.s Hello.ssa gcc -o Hello Hello.s compiler/target/blaise_rtl.a

Compile with unit search paths

compiler/target/blaise –source MyApp.pas
–unit-path src/units
–emit-ir > MyApp.ssa

Emit QBE IR only (useful for debugging the compiler itself)

compiler/target/blaise –source Hello.pas –emit-ir

== Licence

Apache License v2.0 with Runtime Library Exception. See link:LICENSE[LICENSE].

Built with ❤️ for the Pascal community by Graeme.