General tweaks & actual code generation for int f() { return 5; }

.gitignore

@@ -5,3 +5,6 @@ bin/
 *.tab.cpp
 *.yy.cpp
 *.output
+*.gcno
+coverage/
+*.d

Dockerfile

@@ -18,7 +18,9 @@ RUN apt-get update && apt-get install -y --fix-missing \
     build-essential \
     ca-certificates \
     curl \
-    device-tree-compiler
+    device-tree-compiler \
+    lcov \
+    nano
 
 # Install RISC-V Toolchain
 WORKDIR /tmp

Makefile

@@ -1,30 +1,34 @@
-CPPFLAGS += -std=c++20 -W -Wall -g -Wno-unused-parameter -Wno-unused-variable -Wno-unused-function -I include
+# Based on https://stackoverflow.com/a/52036564 which is well worth reading!
 
-CPPFILES := $(wildcard src/*.cpp)
-DEPENDENCIES := $(patsubst %.cpp,%.d,$(CPPFILES))
--include $(DEPENDENCIES)
-OBJFILES := $(patsubst %.cpp,%.o,$(CPPFILES))
-OBJFILES += src/lexer.yy.o src/parser.tab.o
+CXXFLAGS += -std=c++20 -W -Wall -g -Wno-unused-parameter -Wno-unused-variable -Wno-unused-function -fsanitize=address -static-libasan -O0 -rdynamic -I include
+
+SOURCES := $(wildcard src/*.cpp)
+DEPENDENCIES := $(patsubst %.cpp,%.d,$(SOURCES))
+
+OBJECTS := $(patsubst %.cpp,%.o,$(SOURCES))
+OBJECTS += src/parser.tab.o src/lexer.yy.o
 
 
 .PHONY: default clean with_coverage coverage
 
 default: bin/c_compiler
 
-bin/c_compiler : $(OBJFILES)
+bin/c_compiler: $(OBJECTS)
 	@mkdir -p bin
-	g++ $(CPPFLAGS) -o $@ $^
+	g++ $(CXXFLAGS) -o $@ $^
+
+-include $(DEPENDENCIES)
 
 %.o: %.cpp Makefile
-	g++ $(CPPFLAGS) -MMD -MP -c $< -o $@
+	g++ $(CXXFLAGS) -MMD -MP -c $< -o $@
 
 src/parser.tab.cpp src/parser.tab.hpp: src/parser.y
 	bison -v -d src/parser.y -o src/parser.tab.cpp
 
 src/lexer.yy.cpp : src/lexer.flex src/parser.tab.hpp
 	flex -o src/lexer.yy.cpp src/lexer.flex
 
-with_coverage : CPPFLAGS += --coverage
+with_coverage : CXXFLAGS += --coverage
 with_coverage : bin/c_compiler
 
 coverage : coverage/index.html
@@ -38,11 +42,12 @@ coverage/index.html :
 	@find . -name "*.gcda" -delete
 
 clean :
-	@rm -rf coverage
-	@find . -name "*.o" -delete
-	@rm -rf bin/*
+	@rm -rf coverage/
+	@rm -rf src/*.o
+	@rm -rf src/*.d
+	@rm -rf src/*.gcno
+	@rm -rf bin/
 	@rm -f src/*.tab.hpp
 	@rm -f src/*.tab.cpp
 	@rm -f src/*.yy.cpp
 	@rm -f src/*.output
-

compiler_tests/_example/example.c

@@ -1,4 +1,4 @@
 int f()
 {
-    return;
+    return 5;
 }

docs/basic_compiler.md

@@ -1,14 +1,15 @@
 Basic compiler
 ==============
 
-For the first time ever, you are provided with a basic compiler that can lex, parse and generate (incorrect) code for the following program:
+For the first time ever, you are provided with a basic compiler that can lex, parse and generate code for only the following program:
 ```
-int f() {
-  return;
+int f()
+{
+    return 5;
 }
 ```
 
-The output assembly is hardcoded, so that the basic compiler passes one of the provided test cases. However, having a functioning compiler should allow you to hopefully jump-start the development of the actually interesting parts of this coursework while avoiding the common early pitfalls that students have faced in previous years. It should also allow you to better understand the underlying C90 grammar and have an easier time when adding new features.
+Having a somewhat functioning compiler should allow you to get started with development of the interesting parts of this coursework while avoiding the common early pitfalls that students have faced in previous years. It should also allow you to better understand the underlying C90 grammar and have an easier time adding new features.
 
 The provided basic compiler is able to traverse the following AST related to the above program. In order to expand its capabilities, you should develop the parser and the corresponding code generation at the same time - do not try to fully implement one before the other.
 
@@ -17,6 +18,11 @@ The provided basic compiler is able to traverse the following AST related to the
 
 The lexer and parser are loosely based on the "official" grammar covered [here](https://www.lysator.liu.se/c/ANSI-C-grammar-l.html) and [here](https://www.lysator.liu.se/c/ANSI-C-grammar-y.html) respectively. While they should suffice for a significant portions of features, you might need to improve them to implement the more advanced ones. If you find the grammar too complicated to understand, it is also perfectly fine to create your own simple grammar and build upon it as you add more features.
 
-You can follow the patterns introduced for the code generation part of the basic compiler, but you might find adjusting them to your needs be better in the long run. You are recommended to follow the coding style that best suits you while hopefully picking strong design skills throughout the development of your compiler.
+Two versions of the grammar have been provided:
+
+- [parser.y](../src/parser.y) contains a stripped down version of the grammar which contains only the elements from the full grammar that are necessary to parse the above program. **This is the grammar used when you run ./test.sh**.
+- [parser_full.y.example](../src/parser_full.y.example) is the same as `parser.y` but also contains the rest of the C90 grammar not used in the above program. Once you understand how the stripped version works, you have two options: you can extend `parser.y` at your own pace and add pieces of the C90 grammar to it as you implement them; alternatively, you may paste the contents of `parser_full.y.example` into `parser.y` allowing you to parse everything but this may make the file much harder to navigate.
 
+Note that you don't have to use any of the provided grammar examples (or even flex and bison) if you are comfortable with doing something else. However, be warned that TAs will likely only be able to provided limited support for such alternatives.
 
+You can follow the patterns introduced for the code generation part of the basic compiler, but you might find adjusting them to your needs be better in the long run. You are recommended to follow the coding style that best suits you while hopefully picking strong design skills throughout the development of your compiler.

docs/c_compiler.md

@@ -41,7 +41,9 @@ The compilation function is invoked using the flag `-S`, with the source file an
 
     bin/c_compiler -S [source-file.c] -o [dest-file.s]
 
-You can assume that the command-line arguments will always be in this order, and that there will be no spaces in source or destination paths.
+You can assume that the command-line (CLI) arguments will always be in this order, and that there will be no spaces in source or destination paths.
+
+NOTE: the provided starting point in this repository already functions as specified above, so these CLI arguments should work out of the box (unless you decide not to use the provided base compiler).
 
 Input
 -----

docs/coverage.md

@@ -7,4 +7,18 @@ This will generate a webpage `coverage/index.html` with a listing of all the sou
 
 ![Index.html screenshot](./coverage_example.png)
 
-It can also be used automatically on all test files by running `./test.sh coverage`.
+It can also be used automatically on all test files by running `./test.sh coverage`.
+
+## Viewing the coverage webpage
+
+You can view the webpage in your browser by navigating to the coverage directory and running the following command:
+
+```python3 -m http.server```
+
+For example:
+
+```console
+user@host:/workspaces/langproc-cw# cd coverage
+user@host:/workspaces/langproc-cw/coverage# python3 -m http.server
+Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...
+```

docs/environment_guide.md

@@ -12,19 +12,27 @@ Many students develop their compiler in VS Code, as this has good support for co
 1) Install [Docker Desktop](https://www.docker.com/products/docker-desktop/). If you are on Apple M1/M2, make sure to choose the Apple Silicon download.
 2) Open VS Code and install the [Dev Containers](https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers) extension.
 3) Open the top folder of your repo (`/langproc-cw-.../`), in VS Code.
-4) Open the Command Palette in VS Code. You can do this by the shortcut `Ctrl + Shift + P` on Windows or `Cmd + Shift + P` on Mac. Alternatively, you can access this from `View -> Command Palette`.
+4) Open the Command Palette in VS Code:
+    - Windows: `Ctrl + Shift + P`
+    - Mac OS: `Cmd + Shift + P`
+    - Alternatively, you can access this from the menu bar `View -> Command Palette`.
 5) Enter `>Dev Containers: Reopen in Container` into the Command Palette.
-6) After a delay -- depending on how fast your Internet connection can download ~1GB -- you will now be in the container environment. For those interested, VS Code reads the container configuration from the [.devcontainer/devcontainer.json](.devcontainer/devcontainer.json) file.
+6) After a delay you will now be in the container environment.
+    - The delay will vary based on how fast you can download around 1GB over your Internet connection.
+    - For those interested, VS Code reads the container configuration from the [.devcontainer/devcontainer.json](.devcontainer/devcontainer.json) file.
 7) Test that your tools are correctly setup by running `./scripts/toolchain_test.sh` in the VS Code terminal, accessible via `Terminal -> New Terminal`. Your output should look as follows:
 
     ```console
     root@e3221f21a2a1:/workspaces/langproc-env# ./scripts/toolchain_test.sh
 
-    g++ -std=c++20 -W -Wall -g -I include -o bin/c_compiler src/cli.cpp src/compiler.cpp
+    [...]
 
-    Compiling: compiler_tests/_example/example.c
+    Parsing: compiler_tests/_example/example.c
+    AST parsing complete
+    Printing parsed AST...
+    Printed parsed AST to: bin/riscv_example.s.printed
+    Compiling parsed AST...
     Compiled to: bin/riscv_example.s
-
     bbl loader
     Hello from RISC-V
     Test function produced value: 8.700000
@@ -40,8 +48,13 @@ Many students develop their compiler in VS Code, as this has good support for co
 
 1) Install [Docker](https://www.docker.com/products/docker-desktop/). If you are on Apple M1/M2, make sure to choose the Apple Silicon download.
 2) Open a terminal (Powershell on Windows; Terminal on Mac) to the folder containing this file.
-3) Inside that terminal, run `docker build -t compilers_image .`
-4) Once that completes, run `docker run --rm -it -v "${PWD}:/code" -w "/code" --name "compilers_env" compilers_image`.
+3) Inside that terminal, run `docker build -t compilers_image .` to build the Docker container image
+4) Once that completes, run the following command to start the Docker container
+
+    ```bash
+    docker run --rm -it -v "${PWD}:/code" -w "/code" --name "compilers_env" compilers_image
+    ```
+
 5) You should now be inside the LangProc tools container, where you can run `./scripts/toolchain_test.sh` inside the `/code` folder to check that your tools are working correctly. Note that the folder containing this file, as well as any subdirectories, are mounted inside this container under the path `/code`. The output of running the command should look as follows:
 
 
@@ -53,6 +66,12 @@ Many students develop their compiler in VS Code, as this has good support for co
     Compiling: compiler_tests/_example/example.c
     Compiled to: bin/riscv_example.s
 
+    Parsing: compiler_tests/_example/example.c
+    AST parsing complete
+    Printing parsed AST...
+    Printed parsed AST to: bin/riscv_example.s.printed
+    Compiling parsed AST...
+    Compiled to: bin/riscv_example.s
     bbl loader
     Hello from RISC-V
     Test function produced value: 8.700000

include/ast.hpp

@@ -8,10 +8,11 @@
 #include "ast_direct_declarator.hpp"
 #include "ast_function_definition.hpp"
 #include "ast_identifier.hpp"
-#include "ast_jump_statement.hpp"
+#include "ast_statements.hpp"
 #include "ast_node.hpp"
 #include "ast_type_specifier.hpp"
+#include "ast_constant.hpp"
 
-extern Node* parseAST(std::string file_name);
+extern Node *parseAST(std::string file_name);
 
 #endif

include/ast_constant.hpp

@@ -0,0 +1,25 @@
+#ifndef AST_CONSTANT_HPP
+#define AST_CONSTANT_HPP
+
+#include "ast_node.hpp"
+
+class IntConstant : public Node
+{
+private:
+    int value;
+
+public:
+    IntConstant(int _value) : value(_value) {}
+
+    void emitRISC(std::ostream &stream, Context &ctx) const override
+    {
+        stream << "li a0, " << value << std::endl;
+    }
+
+    void print(std::ostream &stream) const override
+    {
+        stream << value;
+    }
+};
+
+#endif

include/ast_context.hpp

@@ -1,9 +1,12 @@
-#ifndef AST_CONTEXT
-#define AST_CONTEXT
+#ifndef AST_CONTEXT_HPP
+#define AST_CONTEXT_HPP
 
-// An object of class Context is passed between AST nodes during compilation to provide adequate context
-class Context {
-  /* TODO decide what goes inside here */
+// An object of class Context is passed between AST nodes during compilation.
+// This can be used to pass around information about what's currently being
+// compiled (e.g. function scope and variable names).
+class Context
+{
+    /* TODO decide what goes inside here */
 };
 
 #endif

include/ast_direct_declarator.hpp

@@ -1,13 +1,21 @@
-#ifndef AST_DIRECT_DECLARATOR
-#define AST_DIRECT_DECLARATOR
+#ifndef AST_DIRECT_DECLARATOR_HPP
+#define AST_DIRECT_DECLARATOR_HPP
 
 #include "ast_node.hpp"
 
-class DirectDeclarator : public Node {
+class DirectDeclarator : public Node
+{
+private:
+    Node *identifier;
+
 public:
-  DirectDeclarator(Node* identifier);
-  ~DirectDeclarator() {};
-  void emitRISC(std::ostream &stream, Context &context) const;
+    DirectDeclarator(Node *_identifier) : identifier(_identifier){};
+    ~DirectDeclarator()
+    {
+        delete identifier;
+    };
+    void emitRISC(std::ostream &stream, Context &context) const;
+    void print(std::ostream &stream) const override;
 };
 
 #endif

include/ast_function_definition.hpp

@@ -3,11 +3,23 @@
 
 #include "ast_node.hpp"
 
-class FunctionDefinition : public Node {
+class FunctionDefinition : public Node
+{
+private:
+    Node *declarationSpecifiers;
+    Node *declarator;
+    Node *compoundStatement;
+
 public:
-  FunctionDefinition(Node* declaration_specifiers, Node* declarator, Node* compound_statement);
-  ~FunctionDefinition() {};
-  void emitRISC(std::ostream &stream, Context &context) const;
+    FunctionDefinition(Node *_declarationSpecifiers, Node *_declarator, Node *_compoundStatement) : declarationSpecifiers(_declarationSpecifiers), declarator(_declarator), compoundStatement(_compoundStatement){};
+    ~FunctionDefinition()
+    {
+        delete declarationSpecifiers;
+        delete declarator;
+        delete compoundStatement;
+    };
+    void emitRISC(std::ostream &stream, Context &context) const;
+    void print(std::ostream &stream) const override;
 };
 
 #endif

include/ast_identifier.hpp

@@ -1,15 +1,21 @@
-#ifndef AST_IDENTIFIER
-#define AST_IDENTIFIER
+#ifndef AST_IDENTIFIER_HPP
+#define AST_IDENTIFIER_HPP
 
 #include "ast_node.hpp"
 
-class Identifier : public Node {
+class Identifier : public Node
+{
 private:
-  std::string* identifier;
+    std::string identifier;
+
 public:
-  Identifier(std::string* _identifier) : identifier(_identifier) {};
-  ~Identifier() {delete identifier;};
-  void emitRISC(std::ostream &stream, Context &context) const;
+    Identifier(std::string _identifier) : identifier(_identifier){};
+    ~Identifier(){};
+    void emitRISC(std::ostream &stream, Context &context) const;
+    void print(std::ostream &stream) const override
+    {
+        stream << identifier;
+    };
 };
 
 #endif