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Printf float with LLVM segfaults

I am trying to invoke printffloating point numbers from LLVM to print. Although it works fine with int, it segfaults when used double.

Here is the code (generated from clang but slightly modified so that it works fine with llc):

@.str = private unnamed_addr constant [3 x i8] c"%f\00", align 1

; Function Attrs: nounwind uwtable
define i32 @main() #0 {
  %1 = alloca i32, align 4
  store i32 0, i32* %1
  %2 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([3 x i8]* @.str, i32 0, i32 0), double 3.140000e+00)
  ret i32 0
}

declare i32 @printf(i8*, ...) #1

attributes #0 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }

This is how I create the executable:

llc main.ll --filetype=obj
ld -lc -e main -dynamic-linker /lib64/ld-linux-x86-64.so.2 main.o -o main

When I run maininside valgrind, I get:

Process terminating with default action of signal 11 (SIGSEGV): dumping core
 General Protection Fault

I read somewhere on this site that I need to align the stack for use printf. If this is a problem, how to do it in LLVM.

Otherwise, what causes this segfault?

I am running 64-bit versions of Linux.

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1 answer

This is NOT a llvm problem. when you run

llc main.ll --filetype=obj
ld -lc -e main -dynamic-linker /lib64/ld-linux-x86-64.so.2 main.o -o main

objact main.o , , main , .

main , , - , _start, , , .

- , . crti.o crtn.o crt1.o, printf libc.so/libc.a, .

, gcc

gcc main.o -o main

, , ref http://blog.techveda.org/building-executables-with-gnu-linker/

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