First LLVM in C (Not C++)

Generate object code and IR code of a simple program using LLVM in Pure C.

Features

• My best attempt to write well documented code
• Design strlen(char* s) function
• Extern printf function
• Call printf function
• Show Hello, {WORLD}
• Print IR LLVM code
• Generate object code in a file
• You are able to easily build an executable file using a linker

AIM

I'm working on compiler projects for some recent years and it's why I'm studying more about the compiler field.

We are working on the ONE Language with the team.

Output of running the program

max@workstation ~]$ ./llvm

; ModuleID = 'module-c'
source_filename = "module-c"

@format = private unnamed_addr constant [12 x i8] c"Hello, %s.\0A\00", align 1
@name = private unnamed_addr constant [9 x i8] c"Max Base\00", align 1
@format2 = private unnamed_addr constant [20 x i8] c"own_len(Name) = %d\0A\00", align 1

define i32 @strlen(i8* %s) {
init:
  %i = alloca i32, align 4
  store i32 0, i32* %i, align 4
  br label %check

check:                                            ; preds = %body, %init
  %0 = load i32, i32* %i, align 4
  %1 = getelementptr i8, i8* %s, i32 %0
  %2 = load i8, i8* %1, align 1
  %3 = icmp ne i8 0, %2
  br i1 %3, label %body, label %end

body:                                             ; preds = %check
  %4 = load i32, i32* %i, align 4
  %5 = add i32 %4, 1
  store i32 %5, i32* %i, align 4
  br label %check

end:                                              ; preds = %check
  %6 = load i32, i32* %i, align 4
  ret i32 %6
}

declare i32 @printf(...)

define void @main() {
entrypoint:
  %printf = call i32 (...) @printf(i8* getelementptr inbounds ([12 x i8], [12 x i8]* @format, i32 0, i32 0), i8* getelementptr inbounds ([9 x i8], [9 x i8]* @name, i32 0, i32 0))
  %0 = call i32 @strlen(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @name, i32 0, i32 0))
  %1 = call i32 (...) @printf(i8* getelementptr inbounds ([20 x i8], [20 x i8]* @format2, i32 0, i32 0), i32 %0)
  ret void
}

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Max Base 2021, An attempt to rewrite and design a compiler by LLVM at C (Not c++) based on studies.