return false;
}
-bool ARMAsmBackend::fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
- const MCRelaxableFragment *DF,
- const MCAsmLayout &Layout) const {
+const char *ARMAsmBackend::reasonForFixupRelaxation(const MCFixup &Fixup,
+ uint64_t Value) const {
switch ((unsigned)Fixup.getKind()) {
case ARM::fixup_arm_thumb_br: {
// Relaxing tB to t2B. tB has a signed 12-bit displacement with the
//
// Relax if the value is too big for a (signed) i8.
int64_t Offset = int64_t(Value) - 4;
- return Offset > 2046 || Offset < -2048;
+ if (Offset > 2046 || Offset < -2048)
+ return "out of range pc-relative fixup value";
+ break;
}
case ARM::fixup_arm_thumb_bcc: {
// Relaxing tBcc to t2Bcc. tBcc has a signed 9-bit displacement with the
//
// Relax if the value is too big for a (signed) i8.
int64_t Offset = int64_t(Value) - 4;
- return Offset > 254 || Offset < -256;
+ if (Offset > 254 || Offset < -256)
+ return "out of range pc-relative fixup value";
+ break;
}
case ARM::fixup_thumb_adr_pcrel_10:
case ARM::fixup_arm_thumb_cp: {
// If the immediate is negative, greater than 1020, or not a multiple
// of four, the wide version of the instruction must be used.
int64_t Offset = int64_t(Value) - 4;
- return Offset > 1020 || Offset < 0 || Offset & 3;
+ if (Offset & 3)
+ return "misaligned pc-relative fixup value";
+ else if (Offset > 1020 || Offset < 0)
+ return "out of range pc-relative fixup value";
+ break;
}
- case ARM::fixup_arm_thumb_cb:
+ case ARM::fixup_arm_thumb_cb: {
// If we have a Thumb CBZ or CBNZ instruction and its target is the next
// instruction it is is actually out of range for the instruction.
// It will be changed to a NOP.
int64_t Offset = (Value & ~1);
- return Offset == 2;
+ if (Offset == 2)
+ return "will be converted to nop";
+ break;
}
- llvm_unreachable("Unexpected fixup kind in fixupNeedsRelaxation()!");
+ default:
+ llvm_unreachable("Unexpected fixup kind in reasonForFixupRelaxation()!");
+ }
+ return nullptr;
+}
+
+bool ARMAsmBackend::fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
+ const MCRelaxableFragment *DF,
+ const MCAsmLayout &Layout) const {
+ return reasonForFixupRelaxation(Fixup, Value);
}
void ARMAsmBackend::relaxInstruction(const MCInst &Inst, MCInst &Res) const {
return Value;
}
-static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
- bool IsPCRel, MCContext *Ctx,
- bool IsLittleEndian) {
+unsigned ARMAsmBackend::adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
+ bool IsPCRel, MCContext *Ctx,
+ bool IsLittleEndian,
+ bool IsResolved) const {
unsigned Kind = Fixup.getKind();
switch (Kind) {
default:
return Value;
}
- case ARM::fixup_thumb_adr_pcrel_10:
- return ((Value - 4) >> 2) & 0xff;
case ARM::fixup_arm_adr_pcrel_12: {
// ARM PC-relative values are offset by 8.
Value -= 8;
((uint16_t)imm10LBits) << 1);
return joinHalfWords(FirstHalf, SecondHalf, IsLittleEndian);
}
+ case ARM::fixup_thumb_adr_pcrel_10:
case ARM::fixup_arm_thumb_cp:
- // Offset by 4, and don't encode the low two bits. Two bytes of that
- // 'off by 4' is implicitly handled by the half-word ordering of the
- // Thumb encoding, so we only need to adjust by 2 here.
- return ((Value - 2) >> 2) & 0xff;
+ // On CPUs supporting Thumb2, this will be relaxed to an ldr.w, otherwise we
+ // could have an error on our hands.
+ if (Ctx && !STI->getFeatureBits()[ARM::FeatureThumb2] && IsResolved) {
+ const char *FixupDiagnostic = reasonForFixupRelaxation(Fixup, Value);
+ if (FixupDiagnostic)
+ Ctx->reportFatalError(Fixup.getLoc(), FixupDiagnostic);
+ }
+ // Offset by 4, and don't encode the low two bits.
+ return ((Value - 4) >> 2) & 0xff;
case ARM::fixup_arm_thumb_cb: {
// Offset by 4 and don't encode the lower bit, which is always 0.
+ // FIXME: diagnose if no Thumb2
uint32_t Binary = (Value - 4) >> 1;
return ((Binary & 0x20) << 4) | ((Binary & 0x1f) << 3);
}
case ARM::fixup_arm_thumb_br:
// Offset by 4 and don't encode the lower bit, which is always 0.
+ if (Ctx && !STI->getFeatureBits()[ARM::FeatureThumb2]) {
+ const char *FixupDiagnostic = reasonForFixupRelaxation(Fixup, Value);
+ if (FixupDiagnostic)
+ Ctx->reportFatalError(Fixup.getLoc(), FixupDiagnostic);
+ }
return ((Value - 4) >> 1) & 0x7ff;
case ARM::fixup_arm_thumb_bcc:
// Offset by 4 and don't encode the lower bit, which is always 0.
+ if (Ctx && !STI->getFeatureBits()[ARM::FeatureThumb2]) {
+ const char *FixupDiagnostic = reasonForFixupRelaxation(Fixup, Value);
+ if (FixupDiagnostic)
+ Ctx->reportFatalError(Fixup.getLoc(), FixupDiagnostic);
+ }
return ((Value - 4) >> 1) & 0xff;
case ARM::fixup_arm_pcrel_10_unscaled: {
Value = Value - 8; // ARM fixups offset by an additional word and don't
// the instruction. This allows adjustFixupValue() to issue a diagnostic
// if the value aren't invalid.
(void)adjustFixupValue(Fixup, Value, false, &Asm.getContext(),
- IsLittleEndian);
+ IsLittleEndian, IsResolved);
}
/// getFixupKindNumBytes - The number of bytes the fixup may change.
unsigned DataSize, uint64_t Value,
bool IsPCRel) const {
unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
- Value = adjustFixupValue(Fixup, Value, IsPCRel, nullptr, IsLittleEndian);
+ Value =
+ adjustFixupValue(Fixup, Value, IsPCRel, nullptr, IsLittleEndian, true);
if (!Value)
return; // Doesn't change encoding.
projects / oota-llvm.git / commitdiff