= 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:** 2293 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.*
febd34db09