RPCSX/llvm
1
0
Fork 0
mirror of https://github.com/RPCSX/llvm.git synced 2024-12-15 07:59:50 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fix constant island pass's handling of tBR_JTr. The offset of the instruction does not have to be 4-byte aligned. Rather, it's the offset + 2 that must be aligned since the instruction expands into:

Browse Source 
mov     pc, r1
        .align  2
LJTI0_0_0:
        .long    LBB0_14

This fixes rdar://8213383. No test case since it's not possible to come up with a suitable small one.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109076 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2010-07-22 02:09:47 +00:00
parent 624e0b2be6
commit b1c857bb7b
1 changed files with 10 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
lib/Target/ARM/ARMConstantIslandPass.cpp
View File

@ -366,6 +366,8 @@ bool ARMConstantIslands::runOnMachineFunction(MachineFunction &MF) {
if (isThumb && !HasFarJump && AFI->isLRSpilledForFarJump())
MadeChange |= UndoLRSpillRestore();
DEBUG(errs() << '\n'; dumpBBs());
BBSizes.clear();
BBOffsets.clear();
WaterList.clear();
@ -509,8 +511,11 @@ void ARMConstantIslands::InitialFunctionScan(MachineFunction &MF,
case ARM::tBR_JTr:
// A Thumb1 table jump may involve padding; for the offsets to
// be right, functions containing these must be 4-byte aligned.
// tBR_JTr expands to a mov pc followed by .align 2 and then the jump
// table entries. So this code checks whether offset of tBR_JTr + 2
// is aligned.
MF.EnsureAlignment(2U);
if ((Offset+MBBSize)%4 != 0 || HasInlineAsm)
if ((Offset+MBBSize+2)%4 != 0 || HasInlineAsm)
// FIXME: Add a pseudo ALIGN instruction instead.
MBBSize += 2; // padding
continue; // Does not get an entry in ImmBranches
@ -915,9 +920,12 @@ void ARMConstantIslands::AdjustBBOffsetsAfter(MachineBasicBlock *BB,
}
// Thumb1 jump tables require padding. They should be at the end;
// following unconditional branches are removed by AnalyzeBranch.
// tBR_JTr expands to a mov pc followed by .align 2 and then the jump
// table entries. So this code checks whether offset of tBR_JTr + 2
// is aligned.
MachineInstr *ThumbJTMI = prior(MBB->end());
if (ThumbJTMI->getOpcode() == ARM::tBR_JTr) {
unsigned NewMIOffset = GetOffsetOf(ThumbJTMI);
unsigned NewMIOffset = GetOffsetOf(ThumbJTMI) + 2;
unsigned OldMIOffset = NewMIOffset - delta;
if ((OldMIOffset%4) == 0 && (NewMIOffset%4) != 0) {
// remove existing padding