ARM/MC/ELF relocation "hello world" for movw/movt.
Lifted adjustFixupValue() from Darwin for sharing w ELF.
Test added
TODO:
refactor ELFObjectWriter::RecordRelocation more.
Possibly share more code with Darwin?
Lots more relocations...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120534 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMAsmBackend.cpp b/lib/Target/ARM/ARMAsmBackend.cpp
index 6267a5a..432d077 100644
--- a/lib/Target/ARM/ARMAsmBackend.cpp
+++ b/lib/Target/ARM/ARMAsmBackend.cpp
@@ -38,6 +38,48 @@
unsigned getPointerSize() const {
return 4;
}
+
+protected:
+ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
+ switch (Kind) {
+ default:
+ llvm_unreachable("Unknown fixup kind!");
+ case FK_Data_4:
+ case ARM::fixup_arm_movt_hi16:
+ case ARM::fixup_arm_movw_lo16:
+ return Value;
+ case ARM::fixup_arm_pcrel_12: {
+ bool isAdd = true;
+ // ARM PC-relative values are offset by 8.
+ Value -= 8;
+ if ((int64_t)Value < 0) {
+ Value = -Value;
+ isAdd = false;
+ }
+ assert ((Value < 4096) && "Out of range pc-relative fixup value!");
+ Value |= isAdd << 23;
+ return Value;
+ }
+ case ARM::fixup_arm_branch:
+ // These values don't encode the low two bits since they're always zero.
+ // Offset by 8 just as above.
+ return (Value - 8) >> 2;
+ case ARM::fixup_arm_vfp_pcrel_12: {
+ // Offset by 8 just as above.
+ Value = Value - 8;
+ bool isAdd = true;
+ if ((int64_t)Value < 0) {
+ Value = -Value;
+ isAdd = false;
+ }
+ // These values don't encode the low two bits since they're always zero.
+ Value >>= 2;
+ assert ((Value < 256) && "Out of range pc-relative fixup value!");
+ Value |= isAdd << 23;
+ return Value;
+ }
+ }
+ }
};
} // end anonymous namespace
@@ -52,10 +94,6 @@
}
bool ARMAsmBackend::WriteNopData(uint64_t Count, MCObjectWriter *OW) const {
-// if ((Count % 4) != 0) {
-// // Fixme: % 2 for Thumb?
-// return false;
-// }
// FIXME: Zero fill for now. That's not right, but at least will get the
// section size right.
for (uint64_t i = 0; i != Count; ++i)
@@ -94,7 +132,39 @@
// Fixme: can we raise this to share code between Darwin and ELF?
void ELFARMAsmBackend::ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
uint64_t Value) const {
- assert(0 && "ELFARMAsmBackend::ApplyFixup() unimplemented");
+ uint32_t Mask = 0;
+ // Fixme: 2 for Thumb
+ int NumBytes = 4;
+ Value = adjustFixupValue(Fixup.getKind(), Value);
+
+ switch (Fixup.getKind()) {
+ default: assert(0 && "Unsupported Fixup kind"); break;
+ case ARM::fixup_arm_branch: {
+ unsigned Lo24 = Value & 0xFFFFFF;
+ Mask = ~(0xFFFFFF);
+ Value = Lo24;
+ }; break;
+ case ARM::fixup_arm_movt_hi16:
+ case ARM::fixup_arm_movw_lo16: {
+ unsigned Hi4 = (Value & 0xF000) >> 12;
+ unsigned Lo12 = Value & 0x0FFF;
+ // inst{19-16} = Hi4;
+ // inst{11-0} = Lo12;
+ Value = (Hi4 << 16) | (Lo12);
+ Mask = ~(0xF0FFF);
+ }; break;
+ }
+
+ assert((Fixup.getOffset() % NumBytes == 0)
+ && "Offset mod NumBytes is nonzero!");
+ // For each byte of the fragment that the fixup touches, mask in the
+ // bits from the fixup value.
+ // The Value has been "split up" into the appropriate bitfields above.
+ // Fixme: how to share code with the .td generated code?
+ for (unsigned i = 0; i != NumBytes; ++i) {
+ DF.getContents()[Fixup.getOffset() + i] &= uint8_t(Mask >> (i * 8));
+ DF.getContents()[Fixup.getOffset() + i] |= uint8_t(Value >> (i * 8));
+ }
}
namespace {
@@ -137,45 +207,6 @@
}
}
-static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
- switch (Kind) {
- default:
- llvm_unreachable("Unknown fixup kind!");
- case FK_Data_4:
- return Value;
- case ARM::fixup_arm_pcrel_12: {
- bool isAdd = true;
- // ARM PC-relative values are offset by 8.
- Value -= 8;
- if ((int64_t)Value < 0) {
- Value = -Value;
- isAdd = false;
- }
- assert ((Value < 4096) && "Out of range pc-relative fixup value!");
- Value |= isAdd << 23;
- return Value;
- }
- case ARM::fixup_arm_branch:
- // These values don't encode the low two bits since they're always zero.
- // Offset by 8 just as above.
- return (Value - 8) >> 2;
- case ARM::fixup_arm_vfp_pcrel_12: {
- // Offset by 8 just as above.
- Value = Value - 8;
- bool isAdd = true;
- if ((int64_t)Value < 0) {
- Value = -Value;
- isAdd = false;
- }
- // These values don't encode the low two bits since they're always zero.
- Value >>= 2;
- assert ((Value < 256) && "Out of range pc-relative fixup value!");
- Value |= isAdd << 23;
- return Value;
- }
- }
-}
-
void DarwinARMAsmBackend::ApplyFixup(const MCFixup &Fixup, MCDataFragment &DF,
uint64_t Value) const {
unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());