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Dmitry Mikushin

2012-Dec-25 06:18 UTC

[LLVMdev] [DragonEgg] Strange call to @"\01__isoc99_fscanf"

Dear all,

First of all, Merry Christmas! :)

While testing a File I/O sample program, I've encountered a link failure
due to missing implementation of "\01__isoc99_fscanf" function. I
think
this function should be named "__isoc99_fscanf" instead. Please see
the
program code and LLVM IR generated by DragonEgg and clang below. It shows
that clang generates "__isoc99_fscanf", while DragonEgg gives
"\01__isoc99_fscanf". We generally use DragonEgg as our compiler
frontend,
so it is more important. What could be the reason of "\01" issue?

Thanks,
- Dima.

marcusmae at M17xR4:~/forge/kernelgen/tests/behavior/fileio$ cat fileio.c
#include <inttypes.h>
#include <stdio.h>

const char* filename = "fileio.txt";

int main(int argc, char* argv[])
{
    if (argc != 2)
    {
        printf("Test KernelGen support for File I/O\n");
        printf("Usage: %s <szarray>\n", argv[0]);
        return 0;
    }

    size_t szarray = (size_t)strtoumax(argv[1], NULL, 0);

    // Write data to file.
    FILE* wfile = fopen(filename, "w");
    if (!wfile)
    {
        fprintf(stderr, "Cannot open output file %s\n", filename);
        return 1;
    }
    for (int i = 0; i < szarray; i++)
        fprintf(wfile, "%d ", i);
    fclose(wfile);

    // Read data from file.
    FILE* rfile = fopen(filename, "r");
    if (!rfile)
    {
        fprintf(stderr, "Cannot open input file %s\n", filename);
        return 1;
    }
    for (int i = 0; i < szarray; i++)
    {
        int val;
        fscanf(rfile, "%d", &val);
        printf("%d ", val);
    }
    printf("\n");
    fclose(rfile);

    return 0;
}

marcusmae at M17xR4:~/forge/kernelgen/tests/behavior/fileio$
kernelgen-dragonegg -v -std=c99 fileio.c -o-
Using built-in specs.
COLLECT_GCC=kernelgen-gfortran
COLLECT_LTO_WRAPPER=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.6.4/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure
--prefix=/home/marcusmae/rpmbuild/BUILDROOT/opt/kernelgen
--program-prefix=kernelgen- --enable-languages=fortran,c++
--with-mpfr-include=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/include/
--with-mpfr-lib=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/lib
--with-gmp-include=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/include/
--with-gmp-lib=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/lib
--with-mpc-include=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/include/
--with-mpc-lib=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/lib
--enable-plugin --enable-gold=default --disable-ld
--with-ld=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/kernelgen-ld
--disable-bootstrap
Thread model: posix
gcc version 4.6.4 20120720 (prerelease) (GCC)
COLLECT_GCC_OPTIONS='-fplugin=dragonegg.so'
'-fplugin-arg-dragonegg-emit-ir'
'-fplugin-arg-dragonegg-llvm-ir-optimize=0' '-S' '-v'
'-std=c99' '-o' '-'
'-mtune=generic' '-march=x86-64'
 /home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.6.4/cc1
-quiet -v -imultilib . -imultiarch x86_64-linux-gnu -iprefix
/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/
-iplugindir=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/plugin
fileio.c
-iplugindir=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/plugin
-quiet -dumpbase fileio.c -mtune=generic -march=x86-64 -auxbase-strip -
-std=c99 -version -fplugin=dragonegg.so -fplugin-arg-dragonegg-emit-ir
-fplugin-arg-dragonegg-llvm-ir-optimize=0 -o -
GNU C (GCC) version 4.6.4 20120720 (prerelease) (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.6.4 20120720 (prerelease), GMP version
5.0.5, MPFR version 3.1.1, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Versions of loaded plugins:
 dragonegg: 3.2svn
ignoring nonexistent directory
"/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/../../../../x86_64-unknown-linux-gnu/include"
ignoring duplicate directory
"/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/include"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring duplicate directory
"/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/include-fixed"
ignoring nonexistent directory
"/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/include
 /home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/include-fixed
 /usr/local/include
 /home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/../../include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
GNU C (GCC) version 4.6.4 20120720 (prerelease) (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.6.4 20120720 (prerelease), GMP version
5.0.5, MPFR version 3.1.1, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Versions of loaded plugins:
 dragonegg: 3.2svn
Compiler executable checksum: 64cde6062a88e8edfe37057c679689e2
; ModuleID = 'fileio.c'
target datalayout
"e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-unknown-linux-gnu"

%struct._IO_FILE = type { i32, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*,
i8*, i8*, %struct._IO_marker*, %struct._IO_FILE*, i32, i32, i64, i16, i8,
[1 x i8], i8*, i64, i8*, i8*, i8*, i8*, i64, i32, [20 x i8] }
%struct._IO_marker = type { %struct._IO_marker*, %struct._IO_FILE*, i32, [4
x i8] }

@filename = unnamed_addr global i8* getelementptr inbounds ([11 x i8]*
@.cst, i64 0, i64 0)
@.cst = linker_private constant [11 x i8] c"fileio.txt\00", align 8
@.cst1 = linker_private constant [36 x i8] c"Test KernelGen support for
File I/O\00", align 64
@.cst2 = linker_private constant [21 x i8] c"Usage: %s
<szarray>\0A\00",
align 8
@.cst3 = linker_private constant [2 x i8] c"w\00", align 8
@.cst4 = linker_private constant [28 x i8] c"Cannot open output file
%s\0A\00", align 8
@stderr = external global %struct._IO_FILE*
@.cst5 = linker_private constant [4 x i8] c"%d \00", align 8
@.cst6 = linker_private constant [2 x i8] c"r\00", align 8
@.cst7 = linker_private constant [27 x i8] c"Cannot open input file
%s\0A\00", align 8
@.cst8 = linker_private constant [3 x i8] c"%d\00", align 8

define i32 @main(i32 %argc, i8** %argv) nounwind uwtable {
entry:
  %argc_addr = alloca i32, align 4
  %argv_addr = alloca i8**, align 8
  %szarray = alloca i64
  %wfile = alloca %struct._IO_FILE*
  %rfile = alloca %struct._IO_FILE*
  %i = alloca i32
  %i1 = alloca i32
  %val = alloca i32
  %"<retval>" = alloca i32
  %"alloca point" = bitcast i32 0 to i32
  store i32 %argc, i32* %argc_addr
  store i8** %argv, i8*** %argv_addr
  %0 = load i32* %argc_addr, align 32
  %1 = load i8*** %argv_addr, align 64
  %"ssa point" = bitcast i32 0 to i32
  br label %"2"

"2":                                              ; preds = %entry
  %2 = icmp ne i32 %0, 2
  br i1 %2, label %"3", label %"4"

"3":                                              ; preds =
%"2"
  %3 = call i32 @puts(i8* getelementptr inbounds ([36 x i8]* @.cst1, i64 0,
i64 0)) nounwind
  %4 = load i8** %1, align 8
  %5 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([21 x i8]*
@.cst2, i64 0, i64 0), i8* %4) nounwind
  br label %"15"

"4":                                              ; preds =
%"2"
  %6 = bitcast i8** %1 to i8*
  %7 = getelementptr i8* %6, i64 8
  %8 = bitcast i8* %7 to i8**
  %9 = load i8** %8, align 8
  %10 = call i64 @strtoumax(i8* noalias %9, i8** noalias null, i32 0)
nounwind
  %11 = load i8** @filename, align 8
  %12 = call %struct._IO_FILE* @fopen(i8* noalias %11, i8* noalias
getelementptr inbounds ([2 x i8]* @.cst3, i64 0, i64 0)) nounwind
  %13 = icmp eq %struct._IO_FILE* %12, null
  br i1 %13, label %"5", label %"6"

"5":                                              ; preds =
%"4"
  %14 = load i8** @filename, align 8
  %15 = load %struct._IO_FILE** @stderr, align 8
  %16 = call i32 (%struct._IO_FILE*, i8*, ...)* @fprintf(%struct._IO_FILE*
noalias %15, i8* noalias getelementptr inbounds ([28 x i8]* @.cst4, i64 0,
i64 0), i8* %14) nounwind
  br label %"15"

"6":                                              ; preds =
%"4"
  br label %"8"

"7":                                              ; preds =
%"8"
  %17 = call i32 (%struct._IO_FILE*, i8*, ...)* @fprintf(%struct._IO_FILE*
noalias %12, i8* noalias getelementptr inbounds ([4 x i8]* @.cst5, i64 0,
i64 0), i32 %19) nounwind
  %18 = add i32 %19, 1
  br label %"8"

"8":                                              ; preds =
%"7", %"6"
  %19 = phi i32 [ %18, %"7" ], [ 0, %"6" ]
  %20 = sext i32 %19 to i64
  %21 = icmp ult i64 %20, %10
  br i1 %21, label %"7", label %"9"

"9":                                              ; preds =
%"8"
  %22 = call i32 @fclose(%struct._IO_FILE* %12) nounwind
  %23 = load i8** @filename, align 8
  %24 = call %struct._IO_FILE* @fopen(i8* noalias %23, i8* noalias
getelementptr inbounds ([2 x i8]* @.cst6, i64 0, i64 0)) nounwind
  %25 = icmp eq %struct._IO_FILE* %24, null
  br i1 %25, label %"10", label %"11"

"10":                                             ; preds =
%"9"
  %26 = load i8** @filename, align 8
  %27 = load %struct._IO_FILE** @stderr, align 8
  %28 = call i32 (%struct._IO_FILE*, i8*, ...)* @fprintf(%struct._IO_FILE*
noalias %27, i8* noalias getelementptr inbounds ([27 x i8]* @.cst7, i64 0,
i64 0), i8* %26) nounwind
  br label %"15"

"11":                                             ; preds =
%"9"
  br label %"13"

"12":                                             ; preds =
%"13"
  %29 = call i32 (%struct._IO_FILE*, i8*, ...)*
@"\01__isoc99_fscanf"(%struct._IO_FILE* noalias %24, i8* noalias
getelementptr inbounds ([3 x i8]* @.cst8, i64 0, i64 0), i32* %val) nounwind
  %30 = load i32* %val, align 4
  %31 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]*
@.cst5, i64 0, i64 0), i32 %30) nounwind
  %32 = add i32 %33, 1
  br label %"13"

"13":                                             ; preds =
%"12", %"11"
  %33 = phi i32 [ %32, %"12" ], [ 0, %"11" ]
  %34 = sext i32 %33 to i64
  %35 = icmp ult i64 %34, %10
  br i1 %35, label %"12", label %"14"

"14":                                             ; preds =
%"13"
  %36 = call i32 @putchar(i32 10) nounwind
  %37 = call i32 @fclose(%struct._IO_FILE* %24) nounwind
  br label %"15"

"15":                                             ; preds =
%"14", %"10",
%"5", %"3"
  %38 = phi i32 [ 0, %"14" ], [ 1, %"10" ], [ 1,
%"5" ], [ 0, %"3" ]
  store i32 %38, i32* %"<retval>", align 1
  br label %return

return:                                           ; preds = %"15"
  %retval = load i32* %"<retval>"
  ret i32 %retval
}

declare i32 @puts(i8*)

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

declare i64 @strtoumax(i8* noalias, i8** noalias, i32) nounwind

declare %struct._IO_FILE* @fopen(i8* noalias, i8* noalias)

declare i32 @fprintf(%struct._IO_FILE* noalias, i8* noalias, ...)

declare i32 @fclose(%struct._IO_FILE*)

declare i32 @"\01__isoc99_fscanf"(%struct._IO_FILE* noalias, i8*
noalias,
...)

declare i32 @putchar(i32)
COMPILER_PATH=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.6.4/:/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../libexec/gcc/:/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/../../../../x86_64-unknown-linux-gnu/bin/
LIBRARY_PATH=/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/:/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/:/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/../../../../lib64/:/lib/x86_64-linux-gnu/:/lib/../lib64/:/usr/lib/x86_64-linux-gnu/:/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-fplugin=dragonegg.so'
'-fplugin-arg-dragonegg-emit-ir'
'-fplugin-arg-dragonegg-llvm-ir-optimize=0' '-S' '-v'
'-std=c99' '-o' '-'
'-mtune=generic' '-march=x86-64'

marcusmae at M17xR4:~/forge/kernelgen/tests/behavior/fileio$ clang -cc1
-I/usr/include
-I/home/marcusmae/rpmbuild/CHROOT/opt/kernelgen/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.6.4/include
-emit-llvm -std=c99 fileio.c -o-
; ModuleID = 'fileio.c'
target datalayout
"e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

%struct._IO_FILE = type { i32, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*,
i8*, i8*, %struct._IO_marker*, %struct._IO_FILE*, i32, i32, i64, i16, i8,
[1 x i8], i8*, i64, i8*, i8*, i8*, i8*, i64, i32, [20 x i8] }
%struct._IO_marker = type { %struct._IO_marker*, %struct._IO_FILE*, i32 }

@.str = private unnamed_addr constant [11 x i8] c"fileio.txt\00",
align 1
@filename = global i8* getelementptr inbounds ([11 x i8]* @.str, i32 0, i32
0), align 8
@.str1 = private unnamed_addr constant [37 x i8] c"Test KernelGen support
for File I/O\0A\00", align 1
@.str2 = private unnamed_addr constant [21 x i8] c"Usage: %s
<szarray>\0A\00", align 1
@.str3 = private unnamed_addr constant [2 x i8] c"w\00", align 1
@stderr = external global %struct._IO_FILE*
@.str4 = private unnamed_addr constant [28 x i8] c"Cannot open output file
%s\0A\00", align 1
@.str5 = private unnamed_addr constant [4 x i8] c"%d \00", align 1
@.str6 = private unnamed_addr constant [2 x i8] c"r\00", align 1
@.str7 = private unnamed_addr constant [27 x i8] c"Cannot open input file
%s\0A\00", align 1
@.str8 = private unnamed_addr constant [3 x i8] c"%d\00", align 1
@.str9 = private unnamed_addr constant [2 x i8] c"\0A\00", align 1

define i32 @main(i32 %argc, i8** %argv) nounwind {
entry:
  %retval = alloca i32, align 4
  %argc.addr = alloca i32, align 4
  %argv.addr = alloca i8**, align 8
  %szarray = alloca i64, align 8
  %wfile = alloca %struct._IO_FILE*, align 8
  %i = alloca i32, align 4
  %rfile = alloca %struct._IO_FILE*, align 8
  %i17 = alloca i32, align 4
  %val = alloca i32, align 4
  store i32 0, i32* %retval
  store i32 %argc, i32* %argc.addr, align 4
  store i8** %argv, i8*** %argv.addr, align 8
  %0 = load i32* %argc.addr, align 4
  %cmp = icmp ne i32 %0, 2
  br i1 %cmp, label %if.then, label %if.end

if.then:                                          ; preds = %entry
  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([37 x
i8]* @.str1, i32 0, i32 0))
  %1 = load i8*** %argv.addr, align 8
  %arrayidx = getelementptr inbounds i8** %1, i64 0
  %2 = load i8** %arrayidx, align 8
  %call1 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([21 x
i8]* @.str2, i32 0, i32 0), i8* %2)
  store i32 0, i32* %retval
  br label %return

if.end:                                           ; preds = %entry
  %3 = load i8*** %argv.addr, align 8
  %arrayidx2 = getelementptr inbounds i8** %3, i64 1
  %4 = load i8** %arrayidx2, align 8
  %call3 = call i64 @strtoumax(i8* %4, i8** null, i32 0) nounwind
  store i64 %call3, i64* %szarray, align 8
  %5 = load i8** @filename, align 8
  %call4 = call %struct._IO_FILE* @fopen(i8* %5, i8* getelementptr inbounds
([2 x i8]* @.str3, i32 0, i32 0))
  store %struct._IO_FILE* %call4, %struct._IO_FILE** %wfile, align 8
  %6 = load %struct._IO_FILE** %wfile, align 8
  %tobool = icmp ne %struct._IO_FILE* %6, null
  br i1 %tobool, label %if.end7, label %if.then5

if.then5:                                         ; preds = %if.end
  %7 = load %struct._IO_FILE** @stderr, align 8
  %8 = load i8** @filename, align 8
  %call6 = call i32 (%struct._IO_FILE*, i8*, ...)*
@fprintf(%struct._IO_FILE* %7, i8* getelementptr inbounds ([28 x i8]*
@.str4, i32 0, i32 0), i8* %8)
  store i32 1, i32* %retval
  br label %return

if.end7:                                          ; preds = %if.end
  store i32 0, i32* %i, align 4
  br label %for.cond

for.cond:                                         ; preds = %for.inc,
%if.end7
  %9 = load i32* %i, align 4
  %conv = sext i32 %9 to i64
  %10 = load i64* %szarray, align 8
  %cmp8 = icmp ult i64 %conv, %10
  br i1 %cmp8, label %for.body, label %for.end

for.body:                                         ; preds = %for.cond
  %11 = load %struct._IO_FILE** %wfile, align 8
  %12 = load i32* %i, align 4
  %call10 = call i32 (%struct._IO_FILE*, i8*, ...)*
@fprintf(%struct._IO_FILE* %11, i8* getelementptr inbounds ([4 x i8]*
@.str5, i32 0, i32 0), i32 %12)
  br label %for.inc

for.inc:                                          ; preds = %for.body
  %13 = load i32* %i, align 4
  %inc = add nsw i32 %13, 1
  store i32 %inc, i32* %i, align 4
  br label %for.cond

for.end:                                          ; preds = %for.cond
  %14 = load %struct._IO_FILE** %wfile, align 8
  %call11 = call i32 @fclose(%struct._IO_FILE* %14)
  %15 = load i8** @filename, align 8
  %call12 = call %struct._IO_FILE* @fopen(i8* %15, i8* getelementptr
inbounds ([2 x i8]* @.str6, i32 0, i32 0))
  store %struct._IO_FILE* %call12, %struct._IO_FILE** %rfile, align 8
  %16 = load %struct._IO_FILE** %rfile, align 8
  %tobool13 = icmp ne %struct._IO_FILE* %16, null
  br i1 %tobool13, label %if.end16, label %if.then14

if.then14:                                        ; preds = %for.end
  %17 = load %struct._IO_FILE** @stderr, align 8
  %18 = load i8** @filename, align 8
  %call15 = call i32 (%struct._IO_FILE*, i8*, ...)*
@fprintf(%struct._IO_FILE* %17, i8* getelementptr inbounds ([27 x i8]*
@.str7, i32 0, i32 0), i8* %18)
  store i32 1, i32* %retval
  br label %return

if.end16:                                         ; preds = %for.end
  store i32 0, i32* %i17, align 4
  br label %for.cond18

for.cond18:                                       ; preds = %for.inc25,
%if.end16
  %19 = load i32* %i17, align 4
  %conv19 = sext i32 %19 to i64
  %20 = load i64* %szarray, align 8
  %cmp20 = icmp ult i64 %conv19, %20
  br i1 %cmp20, label %for.body22, label %for.end27

for.body22:                                       ; preds = %for.cond18
  %21 = load %struct._IO_FILE** %rfile, align 8
  %call23 = call i32 (%struct._IO_FILE*, i8*, ...)*
@__isoc99_fscanf(%struct._IO_FILE* %21, i8* getelementptr inbounds ([3 x
i8]* @.str8, i32 0, i32 0), i32* %val)
  %22 = load i32* %val, align 4
  %call24 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x
i8]* @.str5, i32 0, i32 0), i32 %22)
  br label %for.inc25

for.inc25:                                        ; preds = %for.body22
  %23 = load i32* %i17, align 4
  %inc26 = add nsw i32 %23, 1
  store i32 %inc26, i32* %i17, align 4
  br label %for.cond18

for.end27:                                        ; preds = %for.cond18
  %call28 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([2 x
i8]* @.str9, i32 0, i32 0))
  %24 = load %struct._IO_FILE** %rfile, align 8
  %call29 = call i32 @fclose(%struct._IO_FILE* %24)
  store i32 0, i32* %retval
  br label %return

return:                                           ; preds = %for.end27,
%if.then14, %if.then5, %if.then
  %25 = load i32* %retval
  ret i32 %25
}

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

declare i64 @strtoumax(i8*, i8**, i32) nounwind

declare %struct._IO_FILE* @fopen(i8*, i8*)

declare i32 @fprintf(%struct._IO_FILE*, i8*, ...)

declare i32 @fclose(%struct._IO_FILE*)

declare i32 @__isoc99_fscanf(%struct._IO_FILE*, i8*, ...)
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Anton Korobeynikov

2012-Dec-25 09:40 UTC

head link

[LLVMdev] [DragonEgg] Strange call to @"\01__isoc99_fscanf"

> While testing a File I/O sample program, I've encountered a link
failure due
> to missing implementation of "\01__isoc99_fscanf" function. I
think this
> function should be named "__isoc99_fscanf" instead. Please see
the program
> code and LLVM IR generated by DragonEgg and clang below. It shows that
clang
> generates "__isoc99_fscanf", while DragonEgg gives
"\01__isoc99_fscanf". We
> generally use DragonEgg as our compiler frontend, so it is more important.
> What could be the reason of "\01" issue?\01 is the magic prefix from asm("") thing in C sources. Basically
this is the instruction to mangler not to change the name in any way,
so, it should be emitted to assembler / binary code as
"__isoc99_fscanf".

How does .s / .o look like?

--
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

Dmitry Mikushin

2012-Dec-25 22:03 UTC

head link

[LLVMdev] [DragonEgg] Strange call to @"\01__isoc99_fscanf"

Hi Anton!

Thanks for the hint! You're right: it is "callq   
__isoc99_fscanf" in .s
file. My mistake is that I'm taking a function name directly from CallInst
and trying to dlsym it from the running executable. Now I'm using
mangler.getNameWithPrefix method to get the actual name, and it works.

Best regards,
- D.

2012/12/25 Anton Korobeynikov <anton at korobeynikov.info>
> > While testing a File I/O sample program, I've encountered a link
failure
> due
> > to missing implementation of "\01__isoc99_fscanf" function.
I think this
> > function should be named "__isoc99_fscanf" instead. Please
see the
> program
> > code and LLVM IR generated by DragonEgg and clang below. It shows that
> clang
> > generates "__isoc99_fscanf", while DragonEgg gives
"\01__isoc99_fscanf".
> We
> > generally use DragonEgg as our compiler frontend, so it is more
> important.
> > What could be the reason of "\01" issue?
> \01 is the magic prefix from asm("") thing in C sources.
Basically
> this is the instruction to mangler not to change the name in any way,
> so, it should be emitted to assembler / binary code as
> "__isoc99_fscanf".
>
> How does .s / .o look like?
>
> --
> With best regards, Anton Korobeynikov
> Faculty of Mathematics and Mechanics, Saint Petersburg State University
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