replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

[CodeGen] fix alignment of JUMPTABLE_INSTS on v8M.base 

Summary:
The attached test case fails with "fatal error: error in backend:
misaligned pc-relative fixup value" as the jump table is misaligned.
The EmitAlignment existed already for ARM and Thumb-1 code, but was
missing for Thumb-2.

The test checks that the fatal error disappears when generating an obj
file, as well as checking the align directive is there when producing an
asm file.


Reviewers: rengolin, grosbach, t.p.northover, jmolloy, SjoerdMeijer, samparker

Reviewed By: samparker

Subscribers: samparker, aemerson, llvm-commits

Differential Revision: https://reviews.llvm.org/D29650

llvm-svn: 294950
This commit is contained in:
Sanne Wouda 2017-02-13 14:07:45 +00:00
parent 92497542e7
commit 490d4a6da6
2 changed files with 56 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
llvm/lib/Target/ARM/ARMAsmPrinter.cpp
View File

@ -1142,6 +1142,11 @@ void ARMAsmPrinter::EmitJumpTableInsts(const MachineInstr *MI) {
const MachineOperand &MO1 = MI->getOperand(1);
unsigned JTI = MO1.getIndex();
// Make sure the Thumb jump table is 4-byte aligned. This will be a nop for
// ARM mode tables.
EmitAlignment(2);
// Emit a label for the jump table.
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel(JTI);
OutStreamer->EmitLabel(JTISymbol);

51
llvm/test/CodeGen/ARM/v8m.base-jumptable_alignment.ll Normal file
View File

@ -0,0 +1,51 @@
; RUN: llc -filetype=obj -o /dev/null < %s
; RUN: llc -filetype=asm < %s | FileCheck %s
; ModuleID = 'bugpoint-reduced-simplified.bc'
source_filename = "bugpoint-output-39ed676.bc"
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "thumbv8m.base-arm-none-eabi"
@crc32_tab = external unnamed_addr global [256 x i32], align 4
@g_566 = external global i32**, align 4
define void @main() {
entry:
%0 = load volatile i32**, i32*** @g_566, align 4
br label %func_16.exit.i.i.i
lbl_1394.i.i.i.loopexit: ; preds = %for.cond14.preheader.us.i.i.i
unreachable
func_16.exit.i.i.i: ; preds = %entry
br i1 undef, label %for.cond7.preheader.i.lr.ph.i.i, label %for.end476.i.i.i.loopexit
for.cond7.preheader.i.lr.ph.i.i: ; preds = %func_16.exit.i.i.i
br i1 undef, label %for.end476.i.i.i.loopexit, label %for.cond7.preheader.i.i.preheader.i
for.cond7.preheader.i.i.preheader.i: ; preds = %for.cond7.preheader.i.lr.ph.i.i
br label %for.cond14.preheader.us.i.i.i
for.cond7.preheader.i.us.i.i: ; preds = %for.cond7.preheader.i.lr.ph.i.i
unreachable
for.cond14.preheader.us.i.i.i: ; preds = %for.inc459.us.i.i.i, %for.cond7.preheader.i.i.preheader.i
; CHECK: @ BB#4
; CHECK-NEXT: .p2align 2
switch i4 undef, label %func_1.exit.loopexit [
i4 0, label %for.inc459.us.i.i.i
i4 -5, label %for.inc459.us.i.i.i
i4 2, label %lbl_1394.i.i.i.loopexit
i4 3, label %for.end476.i.i.i.loopexit
]
for.inc459.us.i.i.i: ; preds = %for.cond14.preheader.us.i.i.i, %for.cond14.preheader.us.i.i.i
br label %for.cond14.preheader.us.i.i.i
for.end476.i.i.i.loopexit: ; preds = %for.cond14.preheader.us.i.i.i
unreachable
func_1.exit.loopexit: ; preds = %for.cond14.preheader.us.i.i.i
%arrayidx.i63.i.i5252 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i32 0, i32 undef
unreachable
}