tracc

Thoroughly Rusty ARM64 C Compiler

This is my approach to writing a C compiler, using norasandler's stages It outputs ARM64 code to be compiled with the gcc-aarch64-linux toolchain. If you have an x86_64 host (like I do), use qemu-static, compiling the code with gcc -static and gcc from aarch64-none-linux-gnu (available download is here)

Currently supported stuff

The compiler currently expects an only function, with no parameters, with a list of the following:

• Variable declarations (only ints for the moment)
• Assignments (with their optional binary operators)
• if statements (with else-if chaining)
• blocks inside blocks for scoped variables
• While loops
• The not supported operators are:
  • Pre and post increment
  • Comma operator
  • Array accessing operator (compiler does not support pointers/arrays)

Input file:

int foo() {
  int a = 1;
  int b = 2;
  if (a > b) {
    return a -b;
  } else {
    return a + b;
  }
}

Output assembly:

	.arch armv8-a
	.global foo
	.type foo, %function
foo:
	sub sp, sp, #16
	mov w1, #1
	str w1, [sp]
	mov w2, #2
	str w2, [sp, #4]
	ldr w0, [sp]
	ldr w1, [sp, #4]
	cmp w0, w1
	ble .LBB2
	ldr w0, [sp]
	ldr w1, [sp, #4]
	sub w0, w0, w1
	b   .epilogue
.LBB2:
	ldr w0, [sp]
	ldr w1, [sp, #4]
	add w0, w0, w1
.epilogue:
	add sp, sp, #16
	ret