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Load from the GOT for external symbols in the large, PIC code model 

Do the same handling for external symbols that we do for jump table
symbols and global values.

Fixes one of the cases in PR38385

llvm-svn: 338651
This commit is contained in:
Reid Kleckner 2018-08-01 22:56:05 +00:00
parent c5d7e04052
commit a30a6d2c29
2 changed files with 92 additions and 1 deletions
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2
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -15793,7 +15793,7 @@ X86TargetLowering::LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) const {
Result = DAG.getNode(getGlobalWrapperKind(), DL, PtrVT, Result);
// With PIC, the address is actually $g + Offset.
if (isPositionIndependent() && !Subtarget.is64Bit()) {
if (OpFlag) {
Result =
DAG.getNode(ISD::ADD, DL, PtrVT,
DAG.getNode(X86ISD::GlobalBaseReg, SDLoc(), PtrVT), Result);

91
llvm/test/CodeGen/X86/code-model-elf-memset.ll Normal file
View File

@ -0,0 +1,91 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; Run with --no_x86_scrub_rip because we care a lot about how globals are
; accessed in the code model.
; Memset is interesting because it is an ExternalSymbol reference instead of a
; GlobalValue. Make sure we do the right GOT load for 64-bit large.
; RUN: llc < %s -relocation-model=pic -code-model=small | FileCheck %s --check-prefix=CHECK --check-prefix=SMALL-PIC
; RUN: llc < %s -relocation-model=pic -code-model=medium | FileCheck %s --check-prefix=CHECK --check-prefix=MEDIUM-PIC
; RUN: llc < %s -relocation-model=pic -code-model=large | FileCheck %s --check-prefix=CHECK --check-prefix=LARGE-PIC
; Generated from this C source:
;
; int main() {
; unsigned int a[100] = {0};
; return 0;
; }
; ModuleID = 'model.c'
source_filename = "model.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64--linux"
declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1) #1
define i32 @main() #0 {
; SMALL-PIC-LABEL: main:
; SMALL-PIC: # %bb.0: # %entry
; SMALL-PIC-NEXT: subq $424, %rsp # imm = 0x1A8
; SMALL-PIC-NEXT: .cfi_def_cfa_offset 432
; SMALL-PIC-NEXT: movl $0, {{[0-9]+}}(%rsp)
; SMALL-PIC-NEXT: leaq {{[0-9]+}}(%rsp), %rdi
; SMALL-PIC-NEXT: xorl %esi, %esi
; SMALL-PIC-NEXT: movl $400, %edx # imm = 0x190
; SMALL-PIC-NEXT: callq memset@PLT
; SMALL-PIC-NEXT: xorl %eax, %eax
; SMALL-PIC-NEXT: addq $424, %rsp # imm = 0x1A8
; SMALL-PIC-NEXT: .cfi_def_cfa_offset 8
; SMALL-PIC-NEXT: retq
;
; MEDIUM-PIC-LABEL: main:
; MEDIUM-PIC: # %bb.0: # %entry
; MEDIUM-PIC-NEXT: subq $424, %rsp # imm = 0x1A8
; MEDIUM-PIC-NEXT: .cfi_def_cfa_offset 432
; MEDIUM-PIC-NEXT: movl $0, {{[0-9]+}}(%rsp)
; MEDIUM-PIC-NEXT: leaq {{[0-9]+}}(%rsp), %rdi
; MEDIUM-PIC-NEXT: xorl %esi, %esi
; MEDIUM-PIC-NEXT: movl $400, %edx # imm = 0x190
; MEDIUM-PIC-NEXT: callq memset@PLT
; MEDIUM-PIC-NEXT: xorl %eax, %eax
; MEDIUM-PIC-NEXT: addq $424, %rsp # imm = 0x1A8
; MEDIUM-PIC-NEXT: .cfi_def_cfa_offset 8
; MEDIUM-PIC-NEXT: retq
;
; LARGE-PIC-LABEL: main:
; LARGE-PIC: # %bb.0: # %entry
; LARGE-PIC-NEXT: subq $424, %rsp # imm = 0x1A8
; LARGE-PIC-NEXT: .cfi_def_cfa_offset 432
; LARGE-PIC-NEXT: .Ltmp0:
; LARGE-PIC-NEXT: leaq {{.*}}(%rip), %rax
; LARGE-PIC-NEXT: movabsq $_GLOBAL_OFFSET_TABLE_-.Ltmp0, %rcx
; LARGE-PIC-NEXT: addq %rcx, %rax
; LARGE-PIC-NEXT: movl $0, {{[0-9]+}}(%rsp)
; LARGE-PIC-NEXT: leaq {{[0-9]+}}(%rsp), %rdi
; LARGE-PIC-NEXT: movabsq $memset@GOT, %rcx
; LARGE-PIC-NEXT: xorl %esi, %esi
; LARGE-PIC-NEXT: movl $400, %edx # imm = 0x190
; LARGE-PIC-NEXT: callq *(%rax,%rcx)
; LARGE-PIC-NEXT: xorl %eax, %eax
; LARGE-PIC-NEXT: addq $424, %rsp # imm = 0x1A8
; LARGE-PIC-NEXT: .cfi_def_cfa_offset 8
; LARGE-PIC-NEXT: retq
entry:
%retval = alloca i32, align 4
%a = alloca [100 x i32], align 16
store i32 0, i32* %retval, align 4
%0 = bitcast [100 x i32]* %a to i8*
call void @llvm.memset.p0i8.i64(i8* align 16 %0, i8 0, i64 400, i1 false)
ret i32 0
}
attributes #0 = { noinline nounwind uwtable }
attributes #0 = { argmemonly nounwind uwtable }
!llvm.module.flags = !{!0, !1, !2}
!llvm.ident = !{!3}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 7, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{!"clang version 7.0.0 "}