Undefined reference to `__morestack' when compiling with -O

[sebcrozet]

Since I updated the compiler to:

rustc 0.11-pre (2c22ae4 2014-04-19 04:26:28 -0700)
host: x86_64-unknown-linux-gnu

the following code:

extern crate native;

#[start]
fn start(argc: int, argv: **u8) -> int {
    native::start(argc, argv, main)
}

fn main() {
}

fails to compile with optimizations on:

rustc -O test.rs
error: linking with `cc` failed: exit code: 1
note: cc arguments: '-m64' '-L/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-o' 'test' 'test.o' '-lmorestack' '-nodefaultlibs' '-Wl,--as-needed' '-Wl,-O1' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libnative-83574243-0.11-pre.rlib' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-aad93cea-0.11-pre.rlib' '/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-3574b280-0.11-pre.rlib' '-L.' '-L/home/tortue/trash/.rust' '-L/home/tortue/trash' '-L/home/tortue/.rust' '-Wl,-Bdynamic' '-ldl' '-lpthread' '-lgcc_s' '-lc' '-lm' '-Wl,-rpath,$ORIGIN/../../../usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-Wl,-rpath,/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib' '-lcompiler-rt'
note: /usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libnative-83574243-0.11-pre.rlib(native.o): In function `io::addrinfo::GetAddrInfoRequest::run::ha9bf714109bfa7af1aa::v0.11.pre':
native.rs:(.text+0x28): undefined reference to `__morestack'
/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libnative-83574243-0.11-pre.rlib(native.o): In function `fmt::secret_string::h10210563234607143262::v0.11.pre':
native.rs:(.text+0xda0): undefined reference to `__morestack'
/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libnative-83574243-0.11-pre.rlib(native.o): In function `rt::unwind::begin_unwind::h2680316326101838750::v0.11.pre':
native.rs:(.text+0xe00): undefined reference to `__morestack'
/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libnative-83574243-0.11-pre.rlib(native.o): In function `any::T.Any::get_type_id::h10127464687270589723::v0.11.pre':
native.rs:(.text+0xe90): undefined reference to `__morestack'
/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libnative-83574243-0.11-pre.rlib(native.o): In function `io::net::sockaddr_to_addr::h1c5b17f236d8b4feAsa::v0.11.pre':
native.rs:(.text+0xed0): undefined reference to `__morestack'
/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libnative-83574243-0.11-pre.rlib(native.o):native.rs:(.text+0x1160): more undefined references to `__morestack' follow
collect2: error: ld returned 1 exit status

error: aborting due to previous error

Compiling without -O does work fine.

[alexcrichton]

Can you paste the output of rustc --emit=ir foo.rs?

[sebcrozet]

Output of rustc --emit=ir test.rs:

; ModuleID = 'test.rs'
target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: uwtable
define internal i64 @_ZN5start20ha41e9c28898510a9faa4v0.0E(i64, i8**) unnamed_addr #0 {
entry-block:
  %argc = alloca i64
  %argv = alloca i8**
  %__adjust = alloca { void (i8*)*, i8* }
  store i64 %0, i64* %argc
  store i8** %1, i8*** %argv
  %2 = load i64* %argc
  %3 = load i8*** %argv
  %4 = getelementptr inbounds { void (i8*)*, i8* }* %__adjust, i32 0, i32 0
  store void (i8*)* @_ZN4main14as_closure.983E, void (i8*)** %4
  %5 = getelementptr inbounds { void (i8*)*, i8* }* %__adjust, i32 0, i32 1
  store i8* null, i8** %5
  %6 = call i64 @_ZN5start20h52ed3dec7308a2ebxzd9v0.11.preE(i64 %2, i8** %3, { void (i8*)*, i8* }* nocapture %__adjust)
  ret i64 %6
}

define i64 @main(i64, i8**) unnamed_addr {
top:
  %2 = call i64 @_ZN5start20ha41e9c28898510a9faa4v0.0E(i64 %0, i8** %1)
  ret i64 %2
}

declare i64 @_ZN5start20h52ed3dec7308a2ebxzd9v0.11.preE(i64, i8**, { void (i8*)*, i8* }* noalias) unnamed_addr #1

; Function Attrs: uwtable
define internal void @_ZN4main20ha1e063e2a65e22b5yaa4v0.0E() unnamed_addr #0 {
entry-block:
  ret void
}

define internal void @_ZN4main14as_closure.983E(i8*) unnamed_addr {
entry-block:
  call void @_ZN4main20ha1e063e2a65e22b5yaa4v0.0E()
  ret void
}

attributes #0 = { uwtable "split-stack" }
attributes #1 = { "split-stack" }

Output of rustc -O --emit=ir test.rs:

; ModuleID = 'test.rs'
target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define i64 @main(i64, i8**) unnamed_addr {
top:
  %__adjust.i = alloca { void (i8*)*, i8* }, align 8
  %2 = bitcast { void (i8*)*, i8* }* %__adjust.i to i8*
  call void @llvm.lifetime.start(i64 16, i8* %2)
  %3 = getelementptr inbounds { void (i8*)*, i8* }* %__adjust.i, i64 0, i32 0
  store void (i8*)* @_ZN4main14as_closure.983E, void (i8*)** %3, align 8
  %4 = getelementptr inbounds { void (i8*)*, i8* }* %__adjust.i, i64 0, i32 1
  store i8* null, i8** %4, align 8
  %5 = call i64 @_ZN5start20h52ed3dec7308a2ebxzd9v0.11.preE(i64 %0, i8** %1, { void (i8*)*, i8* }* nocapture %__adjust.i)
  call void @llvm.lifetime.end(i64 16, i8* %2)
  ret i64 %5
}

declare i64 @_ZN5start20h52ed3dec7308a2ebxzd9v0.11.preE(i64, i8**, { void (i8*)*, i8* }* noalias) unnamed_addr #0

; Function Attrs: nounwind readnone
define internal void @_ZN4main14as_closure.983E(i8* nocapture) unnamed_addr #1 {
entry-block:
  ret void
}

; Function Attrs: nounwind
declare void @llvm.lifetime.start(i64, i8* nocapture) #2

; Function Attrs: nounwind
declare void @llvm.lifetime.end(i64, i8* nocapture) #2

attributes #0 = { "split-stack" }
attributes #1 = { nounwind readnone }
attributes #2 = { nounwind }