llvm/test/CodeGen/PowerPC/ppc64le-localentry.ll
Ulrich Weigand dc8dfe1b86 [PowerPC] Fix large code model with the ELFv2 ABI
The global entry point prologue currently assumes that the TOC
associated with a function is less than 2GB away from the function
entry point.  This is always true when using the medium or small
code model, but may not be the case when using the large code model.

This patch adds a new variant of the ELFv2 global entry point prologue
that lifts the 2GB restriction when building with -mcmodel=large.
This works by emitting a quadword containing the distance from the
function entry point to its associated TOC immediately before the
entry point, and then using a prologue like:

ld r2,-8(r12)
add r2,r2,r12

Since creation of the entry point prologue is now split across two
separate routines (PPCLinuxAsmPrinter::EmitFunctionEntryLabel emits
the data word, PPCLinuxAsmPrinter::EmitFunctionBodyStart the prolog
code), I've switched to using named labels instead of just temporaries
to indicate the locations of the global and local entry points and the
new TOC offset data word.

These names are provided by new routines in PPCFunctionInfo modeled
after the existing PPCFunctionInfo::getPICOffsetSymbol.

Note that a corresponding change was committed to GCC here:
https://gcc.gnu.org/ml/gcc-patches/2015-12/msg00355.html

Reviewers: hfinkel

Differential Revision: http://reviews.llvm.org/D15500



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257597 91177308-0d34-0410-b5e6-96231b3b80d8
2016-01-13 13:12:23 +00:00

55 lines
1.5 KiB
LLVM

; RUN: llc -march=ppc64le -mcpu=pwr8 < %s | FileCheck %s
; RUN: llc -march=ppc64le -mcpu=pwr8 -O0 < %s | FileCheck %s
; RUN: llc -march=ppc64le < %s | FileCheck %s
; RUN: llc -march=ppc64le -O0 < %s | FileCheck %s
; The second run of the test case is to ensure the behaviour is the same
; without specifying -mcpu=pwr8 as that is now the baseline for ppc64le.
target datalayout = "e-m:e-i64:64-n32:64"
target triple = "powerpc64le-unknown-linux-gnu"
@number64 = global i64 10, align 8
; CHECK: .abiversion 2
define i64 @use_toc(i64 %a) nounwind {
entry:
; CHECK-LABEL: @use_toc
; CHECK-NEXT: .L{{.*}}:
; CHECK-NEXT: .Lfunc_gep[[FN:[0-9]+]]:
; CHECK-NEXT: addis 2, 12, .TOC.-.Lfunc_gep[[FN]]@ha
; CHECK-NEXT: addi 2, 2, .TOC.-.Lfunc_gep[[FN]]@l
; CHECK-NEXT: .Lfunc_lep[[FN]]:
; CHECK-NEXT: .localentry use_toc, .Lfunc_lep[[FN]]-.Lfunc_gep[[FN]]
; CHECK-NEXT: %entry
%0 = load i64, i64* @number64, align 8
%cmp = icmp eq i64 %0, %a
%conv1 = zext i1 %cmp to i64
ret i64 %conv1
}
declare void @callee()
define void @use_toc_implicit() nounwind {
entry:
; CHECK-LABEL: @use_toc_implicit
; CHECK-NEXT: .L{{.*}}:
; CHECK-NEXT: .Lfunc_gep[[FN:[0-9]+]]:
; CHECK-NEXT: addis 2, 12, .TOC.-.Lfunc_gep[[FN]]@ha
; CHECK-NEXT: addi 2, 2, .TOC.-.Lfunc_gep[[FN]]@l
; CHECK-NEXT: .Lfunc_lep[[FN]]:
; CHECK-NEXT: .localentry use_toc_implicit, .Lfunc_lep[[FN]]-.Lfunc_gep[[FN]]
; CHECK-NEXT: %entry
call void @callee()
ret void
}
define i64 @no_toc(i64 %a) nounwind {
entry:
; CHECK-LABEL: @no_toc
; CHECK-NEXT: .L{{.*}}:
; CHECK-NEXT: %entry
ret i64 %a
}