Hi I’m having a problem with my back end.
This LLVM IR…
; ModuleID = ‘main_clean.ll’
source_filename = “main.ll”
target datalayout = “e-p:16:8-i8:8-i16:8-i32:8-i64:8-f32:8-f64:8-n8-a:8”
target triple = “avr-atmel-linux-gnueabihf”
%Ts5UInt8V = type <{ i8 }>
%Ts6UInt16V = type <{ i16 }>
@“$s4main3rads5UInt8Vvp” = hidden local_unnamed_addr global %Ts5UInt8V zeroinitializer, align 1
@“$s4main3angs6UInt16Vvp” = hidden local_unnamed_addr global %Ts6UInt16V zeroinitializer, align 2
@__swift_reflection_version = linkonce_odr hidden constant i16 3
@_swift1_autolink_entries = private constant [6 x i8] c"-lavr\00", section “.swift1_autolink_entries”, align 2
@llvm.used = appending global [2 x i8*] [i8* bitcast (i16* @__swift_reflection_version to i8*), i8* getelementptr inbounds ([6 x i8], [6 x i8]* @_swift1_autolink_entries, i32 0, i32 0)], section “llvm.metadata”
; Function Attrs: noreturn
define protected i16 @main(i16, i8** nocapture readnone) local_unnamed_addr #0 {
entry:
%2 = tail call swiftcc i16 @“$s3AVR14slowAnalogRead3pins6UInt16Vs5UInt8V_tF”(i8 2)
tail call swiftcc void @“$s3AVR7srandom4seedys6UInt16V_tF”(i16 %2)
tail call swiftcc void @“$s3AVR11SetupSerial8baudRateys6UInt16V_tF”(i16 9600)
%3 = tail call swiftcc i16 @“$s3AVR6randoms5Int16VyF”()
store i8 0, i8* getelementptr inbounds (%Ts5UInt8V, %Ts5UInt8V* @“$s4main3rads5UInt8Vvp”, i16 0, i32 0), align 1
store i16 0, i16* getelementptr inbounds (%Ts6UInt16V, %Ts6UInt16V* @“$s4main3angs6UInt16Vvp”, i16 0, i32 0), align 2
tail call swiftcc void @“$s3AVR5print11unsignedInt10addNewlineys6UInt16V_SbtF”(i16 0, i1 true)
tail call swiftcc void @“$s3AVR5print11unsignedInt10addNewlineys6UInt16V_SbtF”(i16 0, i1 true)
br label %4
; :4: ; preds = %4, %entry
tail call swiftcc void @“$s3AVR4wait2msys6UInt16V_tF”(i16 100)
%5 = tail call swiftcc { i16, i16 } @“$s3AVR11longRandom4s5UInt8V5byte1_AD5byte2AD5byte3AD5byte4tyF”()
%6 = extractvalue { i16, i16 } %5, 1
%temp-coercion.coerced.sroa.5.2.extract.trunc = trunc i16 %6 to i8
tail call swiftcc void @“$s3AVR5print15unsignedTinyInt10addNewlineys5UInt8V_SbtF”(i8 %temp-coercion.coerced.sroa.5.2.extract.trunc, i1 true)
br label %4
}
declare swiftcc i16 @“$s3AVR14slowAnalogRead3pins6UInt16Vs5UInt8V_tF”(i8) local_unnamed_addr #1
declare swiftcc void @“$s3AVR7srandom4seedys6UInt16V_tF”(i16) local_unnamed_addr #1
declare swiftcc void @“$s3AVR11SetupSerial8baudRateys6UInt16V_tF”(i16) local_unnamed_addr #1
declare swiftcc i16 @“$s3AVR6randoms5Int16VyF”() local_unnamed_addr #1
declare swiftcc void @“$s3AVR5print11unsignedInt10addNewlineys6UInt16V_SbtF”(i16, i1) local_unnamed_addr #1
declare swiftcc void @“$s3AVR4wait2msys6UInt16V_tF”(i16) local_unnamed_addr #1
declare swiftcc { i16, i16 } @“$s3AVR11longRandom4s5UInt8V5byte1_AD5byte2AD5byte3AD5byte4tyF”() local_unnamed_addr #1
declare swiftcc void @“$s3AVR5print15unsignedTinyInt10addNewlineys5UInt8V_SbtF”(i8, i1) local_unnamed_addr #1
; Function Attrs: norecurse nounwind readnone
define hidden swiftcc i16 @“$s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF”(i32) local_unnamed_addr #2 {
entry:
ret i16 0
}
attributes #0 = { noreturn “no-frame-pointer-elim”=“true” “no-frame-pointer-elim-non-leaf” }
attributes #1 = { “no-frame-pointer-elim”=“true” “no-frame-pointer-elim-non-leaf” }
attributes #2 = { norecurse nounwind readnone “no-frame-pointer-elim”=“true” “no-frame-pointer-elim-non-leaf” }
!swift.module.flags = !{!0}
!0 = !{!“standard-library”, i1 false}
…produces this assembly when compiled with llc with the AVR back end…
.text
.file “main.ll”
.protected main ; – Begin function main
.globl main
.p2align 1
.type main,@function
main: ; @main
; %bb.0: ; %entry
push r16
push r17
ldi r24, 2
call ($s3AVR14slowAnalogRead3pins6UInt16Vs5UInt8V_tF)
call ($s3AVR7srandom4seedys6UInt16V_tF)
ldi r24, 128
ldi r25, 37
call ($s3AVR11SetupSerial8baudRateys6UInt16V_tF)
call ($s3AVR6randoms5Int16VyF)
ldi r24, 0
sts ($s4main3rads5UInt8Vvp), r24
ldi r16, 0
ldi r17, 0
sts ($s4main3angs6UInt16Vvp)+1, r17
sts ($s4main3angs6UInt16Vvp), r16
movw r24, r16
ldi r22, 1
call ($s3AVR5print11unsignedInt10addNewlineys6UInt16V_SbtF)
movw r24, r16
ldi r22, 1
call ($s3AVR5print11unsignedInt10addNewlineys6UInt16V_SbtF)
ldi r16, 100
ldi r17, 0
LBB0_1: ; =>This Inner Loop Header: Depth=1
movw r24, r16
call ($s3AVR4wait2msys6UInt16V_tF)
call ($s3AVR11longRandom4s5UInt8V5byte1_AD5byte2AD5byte3AD5byte4tyF)
; kill: def $r24 killed $r24 killed $r25r24
ldi r22, 1
call ($s3AVR5print15unsignedTinyInt10addNewlineys5UInt8V_SbtF)
rjmp LBB0_1
.Lfunc_end0:
.size main, .Lfunc_end0-main
; – End function
.hidden $s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF ; – Begin function $s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF
.globl $s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF
.p2align 1
.type $s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF,@function
$s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF: ; @“$s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF”
; %bb.0: ; %entry
ldi r24, 0
ldi r25, 0
ret
.Lfunc_end1:
.size $s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF, .Lfunc_end1-($s4main13setServoAngle5angles6UInt16Vs6UInt32V_tF)
; – End function
.hidden $s4main3rads5UInt8Vvp ; @“$s4main3rads5UInt8Vvp”
.type $s4main3rads5UInt8Vvp,@object
.section .bss,“aw”,@nobits
.globl $s4main3rads5UInt8Vvp
$s4main3rads5UInt8Vvp:
.zero 1
.size $s4main3rads5UInt8Vvp, 1
.hidden $s4main3angs6UInt16Vvp ; @“$s4main3angs6UInt16Vvp”
.type $s4main3angs6UInt16Vvp,@object
.globl $s4main3angs6UInt16Vvp
.p2align 1
$s4main3angs6UInt16Vvp:
.zero 2
.size $s4main3angs6UInt16Vvp, 2
.hidden __swift_reflection_version ; @__swift_reflection_version
.type __swift_reflection_version,@object
.section .rodata,“a”,@progbits
.weak __swift_reflection_version
__swift_reflection_version:
.short 3 ; 0x3
.size __swift_reflection_version, 2
.type _swift1_autolink_entries,@object ; @_swift1_autolink_entries
.section .swift1_autolink_entries,“a”,@progbits
.p2align 1
_swift1_autolink_entries:
.asciz “-lavr”
.size _swift1_autolink_entries, 6
; Declaring this symbol tells the CRT that it should
;copy all variables from program memory to RAM on startup
.globl __do_copy_data
; Declaring this symbol tells the CRT that it should
;clear the zeroed data section on startup
.globl __do_clear_bss
…which gcc 7.3.0 cannot compile, giving errors like…
main.s: Assembler messages:
main.s:12: Error: missing ‘)’
main.s:12: Error: missing operand
main.s:12: Error: unknown opcode s3avr14slo' main.s:13: Error: missing ')' main.s:13: Error: missing operand main.s:13: Error: unknown opcode s3avr7sran’
main.s:16: Error: missing ‘)’
main.s:16: Error: missing operand
main.s:16: Error: unknown opcode `s3avr11set’
I think the identifiers in the LLVM IR are getting garbled?
I was expecting assembly code like…
call “$s3AVR4wait2msys6UInt16V_tF”
and
“$s4main3rads5UInt8Vvp”:
.zero 1
Is this a bug in the AVR back end or is LLVM llc supposed to do this?
Thanks for any advice/help you guys can give.
Cheers,
Carl