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Add support for binary encoding of ARM 'adr' instructions referencing constant

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pool entries (LEApcrel pseudo). Ongoing saga of rdar://8542291.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120635 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach
2010-12-02 00:28:45 +00:00
parent 317bafb82c
commit dff84b0325
7 changed files with 65 additions and 41 deletions
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21
lib/Target/ARM/ARMAsmBackend.cpp
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@ -7,8 +7,8 @@
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetAsmBackend.h"
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMFixupKinds.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCAssembler.h"
@ -21,6 +21,7 @@
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetAsmBackend.h"
#include "llvm/Target/TargetRegistry.h"
using namespace llvm;
@ -67,7 +68,7 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
case ARM::fixup_arm_movt_hi16:
case ARM::fixup_arm_movw_lo16:
return Value;
case ARM::fixup_arm_pcrel_12: {
case ARM::fixup_arm_ldst_pcrel_12: {
bool isAdd = true;
// ARM PC-relative values are offset by 8.
Value -= 8;
@ -79,6 +80,19 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
Value |= isAdd << 23;
return Value;
}
case ARM::fixup_arm_adr_pcrel_12: {
// ARM PC-relative values are offset by 8.
Value -= 8;
unsigned opc = 4; // bits {24-21}. Default to add: 0b0100
if ((int64_t)Value < 0) {
Value = -Value;
opc = 2; // 0b0010
}
assert(ARM_AM::getSOImmVal(Value) != -1 &&
"Out of range pc-relative fixup value!");
// Encode the immediate and shift the opcode into place.
return ARM_AM::getSOImmVal(Value) | (opc << 21);
}
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.
@ -200,8 +214,9 @@ static unsigned getFixupKindNumBytes(unsigned Kind) {
switch (Kind) {
default: llvm_unreachable("Unknown fixup kind!");
case FK_Data_4: return 4;
case ARM::fixup_arm_pcrel_12: return 3;
case ARM::fixup_arm_ldst_pcrel_12: return 3;
case ARM::fixup_arm_pcrel_10: return 3;
case ARM::fixup_arm_adr_pcrel_12: return 3;
case ARM::fixup_arm_branch: return 3;
}
}