1. Support ELF pcrel relocations for movw/movt:

R_ARM_MOVT_PREL and R_ARM_MOVW_PREL_NC.
2. Fix minor bug in ARMAsmPrinter - treat bitfield flag as a bitfield, not an enum.
3. Add support for 3 new elf section types (no-ops)




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123294 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jason W Kim 2011-01-12 00:19:25 +00:00
parent 9081b4b4cf
commit 86a97f2e4d
6 changed files with 84 additions and 5 deletions

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@ -1268,6 +1268,9 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm,
case ELF::SHT_NOTE:
case ELF::SHT_NULL:
case ELF::SHT_ARM_ATTRIBUTES:
case ELF::SHT_INIT_ARRAY:
case ELF::SHT_FINI_ARRAY:
case ELF::SHT_PREINIT_ARRAY:
// Nothing to do.
break;
@ -1490,6 +1493,13 @@ unsigned ARMELFObjectWriter::GetRelocType(const MCValue &Target,
default:
Type = ELF::R_ARM_CALL; break;
} break;
case ARM::fixup_arm_movt_hi16:
case ARM::fixup_arm_movt_hi16_pcrel:
Type = ELF::R_ARM_MOVT_PREL; break;
case ARM::fixup_arm_movw_lo16:
case ARM::fixup_arm_movw_lo16_pcrel:
Type = ELF::R_ARM_MOVW_PREL_NC; break;
}
} else {
switch ((unsigned)Fixup.getKind()) {

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@ -78,6 +78,8 @@ public:
{ "fixup_arm_thumb_bcc", 1, 8, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_arm_movt_hi16", 0, 16, 0 },
{ "fixup_arm_movw_lo16", 0, 16, 0 },
{ "fixup_arm_movt_hi16_pcrel", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
{ "fixup_arm_movw_lo16_pcrel", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
};
if (Kind < FirstTargetFixupKind)
@ -156,7 +158,9 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
case FK_Data_4:
return Value;
case ARM::fixup_arm_movt_hi16:
case ARM::fixup_arm_movw_lo16: {
case ARM::fixup_arm_movw_lo16:
case ARM::fixup_arm_movt_hi16_pcrel:
case ARM::fixup_arm_movw_lo16_pcrel: {
unsigned Hi4 = (Value & 0xF000) >> 12;
unsigned Lo12 = Value & 0x0FFF;
// inst{19-16} = Hi4;

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@ -189,10 +189,10 @@ void ARMAsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
int64_t Imm = MO.getImm();
O << '#';
if ((Modifier && strcmp(Modifier, "lo16") == 0) ||
(TF == ARMII::MO_LO16))
(TF & ARMII::MO_LO16))
O << ":lower16:";
else if ((Modifier && strcmp(Modifier, "hi16") == 0) ||
(TF == ARMII::MO_HI16))
(TF & ARMII::MO_HI16))
O << ":upper16:";
O << Imm;
break;

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@ -74,6 +74,11 @@ enum Fixups {
fixup_arm_movt_hi16, // :upper16:
fixup_arm_movw_lo16, // :lower16:
// It is possible to create an "immediate" that happens to be pcrel.
// Needed to support ELF::R_ARM_MOVT_PREL and ELF::R_ARM_MOVW_PREL_NC
fixup_arm_movt_hi16_pcrel, // :upper16:
fixup_arm_movw_lo16_pcrel, // :lower16:
// Marker
LastTargetFixupKind,
NumTargetFixupKinds = LastTargetFixupKind - FirstTargetFixupKind

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@ -626,6 +626,32 @@ getT2AddrModeImm8s4OpValue(const MCInst &MI, unsigned OpIdx,
return Binary;
}
// FIXME: This routine needs to handle more MCExpr types
static const MCSymbolRefExpr *FindLHSymExpr(const MCExpr *E) {
// recurse left child until finding a MCSymbolRefExpr
switch (E->getKind()) {
case MCExpr::SymbolRef:
return cast<MCSymbolRefExpr>(E);
case MCExpr::Binary:
return FindLHSymExpr(cast<MCBinaryExpr>(E)->getLHS());
default:
return NULL;
}
}
// FIXME: This routine assumes that a binary
// expression will always result in a PCRel expression
// In reality, its only true if one or more subexpressions
// is itself a PCRel (i.e. "." in asm or some other pcrel construct)
// but this is good enough for now.
static bool EvaluateAsPCRel(const MCExpr *Expr) {
switch (Expr->getKind()) {
case MCExpr::SymbolRef: return false;
case MCExpr::Binary: return true;
default: assert(0 && "Unexpected expression type");
}
}
uint32_t ARMMCCodeEmitter::
getMovtImmOpValue(const MCInst &MI, unsigned OpIdx,
SmallVectorImpl<MCFixup> &Fixups) const {
@ -635,18 +661,27 @@ getMovtImmOpValue(const MCInst &MI, unsigned OpIdx,
if (MO.isImm()) {
return static_cast<unsigned>(MO.getImm());
} else if (const MCSymbolRefExpr *Expr =
dyn_cast<MCSymbolRefExpr>(MO.getExpr())) {
FindLHSymExpr(MO.getExpr())) {
// FIXME: :lower16: and :upper16: should be applicable to
// to whole expression, not just symbolrefs
// Until that change takes place, this hack is required to
// generate working code.
const MCExpr *OrigExpr = MO.getExpr();
MCFixupKind Kind;
switch (Expr->getKind()) {
default: assert(0 && "Unsupported ARMFixup");
case MCSymbolRefExpr::VK_ARM_HI16:
Kind = MCFixupKind(ARM::fixup_arm_movt_hi16);
if (EvaluateAsPCRel(OrigExpr))
Kind = MCFixupKind(ARM::fixup_arm_movt_hi16_pcrel);
break;
case MCSymbolRefExpr::VK_ARM_LO16:
Kind = MCFixupKind(ARM::fixup_arm_movw_lo16);
if (EvaluateAsPCRel(OrigExpr))
Kind = MCFixupKind(ARM::fixup_arm_movw_lo16_pcrel);
break;
}
Fixups.push_back(MCFixup::Create(0, Expr, Kind));
Fixups.push_back(MCFixup::Create(0, OrigExpr, Kind));
return 0;
};
llvm_unreachable("Unsupported MCExpr type in MCOperand!");

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@ -1,4 +1,6 @@
@ RUN: llvm-mc %s -triple=armv7-linux-gnueabi | FileCheck -check-prefix=ASM %s
@ RUN: llvm-mc %s -triple=armv7-linux-gnueabi -filetype=obj -o - | \
@ RUN: elf-dump --dump-section-data | FileCheck -check-prefix=OBJ %s
.syntax unified
.text
.globl barf
@ -12,3 +14,26 @@ barf: @ @barf
@ ASM: movw r0, :lower16:GOT-(.LPC0_2+8)
@ ASM-NEXT: movt r0, :upper16:GOT-(.LPC0_2+16)
@@ make sure that the text section fixups are sane too
@ OBJ: '.text'
@ OBJ-NEXT: 'sh_type', 0x00000001
@ OBJ-NEXT: 'sh_flags', 0x00000006
@ OBJ-NEXT: 'sh_addr', 0x00000000
@ OBJ-NEXT: 'sh_offset', 0x00000034
@ OBJ-NEXT: 'sh_size', 0x00000008
@ OBJ-NEXT: 'sh_link', 0x00000000
@ OBJ-NEXT: 'sh_info', 0x00000000
@ OBJ-NEXT: 'sh_addralign', 0x00000004
@ OBJ-NEXT: 'sh_entsize', 0x00000000
@ OBJ-NEXT: '_section_data', 'f00f0fe3 ec0f4fe3'
@ OBJ: Relocation 0x00000000
@ OBJ-NEXT: 'r_offset', 0x00000000
@ OBJ-NEXT: 'r_sym'
@ OBJ-NEXT: 'r_type', 0x0000002d
@ OBJ: Relocation 0x00000001
@ OBJ-NEXT: 'r_offset', 0x00000004
@ OBJ-NEXT: 'r_sym'
@ OBJ-NEXT: 'r_type', 0x0000002e