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[COFF, ARM64] Don't put jump table into a separate COFF section for EK_LabelDifference32

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Windows ARM64 has PIC relocation model and uses jump table kind
EK_LabelDifference32. This produces jump table entry as
".word LBB123 - LJTI1_2" which represents the distance between the block
and jump table.

A new relocation type (IMAGE_REL_ARM64_REL32) is needed to do the fixup
correctly if they are in different COFF section.

This change saves the jump table to the same COFF section as the
associated code. An ideal fix could be utilizing IMAGE_REL_ARM64_REL32
relocation type.

Patch by Tom Tan!

Differential Revision: https://reviews.llvm.org/D57277

llvm-svn: 352465
This commit is contained in:
Martin Storsjo 2019-01-29 09:36:48 +00:00
parent 5d69ad9388
commit 30a71b482a
3 changed files with 61 additions and 4 deletions
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13
lib/Target/AArch64/AArch64AsmPrinter.cpp
View File

@ -578,9 +578,18 @@ void AArch64AsmPrinter::EmitJumpTableInfo() {
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return;
const Function &F = MF->getFunction();
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
MCSection *ReadOnlySec = TLOF.getSectionForJumpTable(MF->getFunction(), TM);
OutStreamer->SwitchSection(ReadOnlySec);
bool JTInDiffSection =
!STI->isTargetCOFF() ||
!TLOF.shouldPutJumpTableInFunctionSection(
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
F);
if (JTInDiffSection) {
// Drop it in the readonly section.
MCSection *ReadOnlySec = TLOF.getSectionForJumpTable(F, TM);
OutStreamer->SwitchSection(ReadOnlySec);
}
auto AFI = MF->getInfo<AArch64FunctionInfo>();
for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {

4
lib/Target/AArch64/AArch64TargetMachine.cpp
View File

@ -208,8 +208,8 @@ static std::string computeDataLayout(const Triple &TT,
static Reloc::Model getEffectiveRelocModel(const Triple &TT,
Optional<Reloc::Model> RM) {
// AArch64 Darwin is always PIC.
if (TT.isOSDarwin())
// AArch64 Darwin and Windows are always PIC.
if (TT.isOSDarwin() || TT.isOSWindows())
return Reloc::PIC_;
// On ELF platforms the default static relocation model has a smart enough
// linker to cope with referencing external symbols defined in a shared

48
test/CodeGen/AArch64/win64-jumptable.ll Normal file
View File

@ -0,0 +1,48 @@
; RUN: llc -o - %s -mtriple=aarch64-windows -aarch64-enable-compress-jump-tables=0 | FileCheck %s
define void @f(i32 %x) {
entry:
switch i32 %x, label %sw.epilog [
i32 0, label %sw.bb
i32 1, label %sw.bb1
i32 2, label %sw.bb2
i32 3, label %sw.bb3
]
sw.bb: ; preds = %entry
tail call void @g(i32 0) #2
br label %sw.epilog
sw.bb1: ; preds = %entry
tail call void @g(i32 1) #2
br label %sw.epilog
sw.bb2: ; preds = %entry
tail call void @g(i32 2) #2
br label %sw.epilog
sw.bb3: ; preds = %entry
tail call void @g(i32 3) #2
br label %sw.epilog
sw.epilog: ; preds = %entry, %sw.bb3, %sw.bb2, %sw.bb1, %sw.bb
tail call void @g(i32 10) #2
ret void
}
declare void @g(i32)
; CHECK: .text
; CHECK: f:
; CHECK: .seh_proc f
; CHECK: b g
; CHECK-NEXT: .p2align 2
; CHECK-NEXT: .LJTI0_0:
; CHECK: .word .LBB0_2-.LJTI0_0
; CHECK: .word .LBB0_3-.LJTI0_0
; CHECK: .word .LBB0_4-.LJTI0_0
; CHECK: .word .LBB0_5-.LJTI0_0
; CHECK: .section .xdata,"dr"
; CHECK: .seh_handlerdata
; CHECK: .text
; CHECK: .seh_endproc