R32V2020 C Compiler

Not Yet Implemented

• clang is used to create LLVM IR
• Install clang

sudo apt-get install clang

• Create LLVM IR

clang -S -emit-llvm foo.c

• Example Source File

int square(int a)
{
        return(a*a);
}

• .ll Output for example

; ModuleID = 'foo.c'
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "armv6--linux-gnueabihf"

; Function Attrs: nounwind
define i32 @square(i32 %a) #0 {
  %1 = alloca i32, align 4
  store i32 %a, i32* %1, align 4
  %2 = load i32, i32* %1, align 4
  %3 = load i32, i32* %1, align 4
  %4 = mul nsw i32 %2, %3
  ret i32 %4
}

• Writing an LLVM Backend
• Tutorial for Writing Backend for a RISC style CPU (very similar (ISA)
• Writing a backend for the Tricore CPU (pdf)
  • Slide show for Tricore CPU
• Godbolt Compiler Explorer - set option to

-S -emit-llvm -O0

• LLVM Installers includes clang
  • Windows install option
  • Command line

"c:\Program Files\LLVM\bin\clang" -S -emit-llvm -O0 foo.c

GCC Toolchain

• How To Retarget the GNU Toolchain in 21 Patches