llvm-6502/test/CodeGen/PowerPC/ppc64-calls.ll
Ulrich Weigand 336da8cdc5 [PowerPC] Do not use BLA with the 64-bit SVR4 ABI
The PowerPC back-end uses BLA to implement calls to functions at
known-constant addresses, which is apparently used for certain
system routines on Darwin.

However, with the 64-bit SVR4 ABI, this is actually incorrect.
An immediate function pointer value on this platform is not
directly usable as a target address for BLA:
- in the ELFv1 ABI, the function pointer value refers to the
  *function descriptor*, not the code address
- in the ELFv2 ABI, the function pointer value refers to the
  global entry point, but BL(A) would only be correct when
  calling the *local* entry point

This bug didn't show up since using immediate function pointer
values is not usually done in the 64-bit SVR4 ABI in the first
place.  However, I ran into this issue with a certain use case
of LLVM as JIT, where immediate function pointer values were
uses to implement callbacks from JITted code to helpers in
statically compiled code.

Fixed by simply not using BLA with the 64-bit SVR4 ABI.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211174 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-18 16:14:04 +00:00

55 lines
1.4 KiB
LLVM

; RUN: llc < %s -march=ppc64 | FileCheck %s
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-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
define void @foo() nounwind readnone noinline {
ret void
}
define weak void @foo_weak() nounwind {
ret void
}
; Calls to local function does not require the TOC restore 'nop'
define void @test_direct() nounwind readnone {
; CHECK-LABEL: test_direct:
tail call void @foo() nounwind
; CHECK: bl foo
; CHECK-NOT: nop
ret void
}
; Calls to weak function requires a TOC restore 'nop' because they
; may be overridden in a different module.
define void @test_weak() nounwind readnone {
; CHECK-LABEL: test_weak:
tail call void @foo_weak() nounwind
; CHECK: bl foo
; CHECK-NEXT: nop
ret void
}
; Indirect calls requires a full stub creation
define void @test_indirect(void ()* nocapture %fp) nounwind {
; CHECK-LABEL: test_indirect:
tail call void %fp() nounwind
; CHECK: ld [[FP:[0-9]+]], 0(3)
; CHECK: ld 11, 16(3)
; CHECK: ld 2, 8(3)
; CHECK-NEXT: mtctr [[FP]]
; CHECK-NEXT: bctrl
; CHECK-NEXT: ld 2, 40(1)
ret void
}
declare double @sin(double) nounwind
; External functions call should also have a 'nop'
define double @test_external(double %x) nounwind {
; CHECK-LABEL: test_external:
%call = tail call double @sin(double %x) nounwind
; CHECK: bl sin
; CHECK-NEXT: nop
ret double %call
}