[llvm] r208076 - ARM: For thumb fixups store halfwords high first and low second
Christian Pirker
cpirker at a-bix.com
Tue May 6 03:05:11 PDT 2014
Author: cpirker
Date: Tue May 6 05:05:11 2014
New Revision: 208076
URL: http://llvm.org/viewvc/llvm-project?rev=208076&view=rev
Log:
ARM: For thumb fixups store halfwords high first and low second
Added:
llvm/trunk/test/MC/ARM/thumb2be-b.w-encoding.s
Modified:
llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
Modified: llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp?rev=208076&r1=208075&r2=208076&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp (original)
+++ llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp Tue May 6 05:05:11 2014
@@ -306,8 +306,36 @@ bool ARMAsmBackend::writeNopData(uint64_
return true;
}
+static uint32_t swapHalfWords(uint32_t Value, bool IsLittleEndian) {
+ if (IsLittleEndian) {
+ // Note that the halfwords are stored high first and low second in thumb;
+ // so we need to swap the fixup value here to map properly.
+ uint32_t Swapped = (Value & 0xFFFF0000) >> 16;
+ Swapped |= (Value & 0x0000FFFF) << 16;
+ return Swapped;
+ }
+ else
+ return Value;
+}
+
+static uint32_t joinHalfWords(uint32_t FirstHalf, uint32_t SecondHalf,
+ bool IsLittleEndian) {
+ uint32_t Value;
+
+ if (IsLittleEndian) {
+ Value = (SecondHalf & 0xFFFF) << 16;
+ Value |= (FirstHalf & 0xFFFF);
+ } else {
+ Value = (SecondHalf & 0xFFFF);
+ Value |= (FirstHalf & 0xFFFF) << 16;
+ }
+
+ return Value;
+}
+
static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
- bool IsPCRel, MCContext *Ctx) {
+ bool IsPCRel, MCContext *Ctx,
+ bool IsLittleEndian) {
unsigned Kind = Fixup.getKind();
switch (Kind) {
default:
@@ -344,9 +372,7 @@ static unsigned adjustFixupValue(const M
// inst{14-12} = Mid3;
// inst{7-0} = Lo8;
Value = (Hi4 << 16) | (i << 26) | (Mid3 << 12) | (Lo8);
- uint64_t swapped = (Value & 0xFFFF0000) >> 16;
- swapped |= (Value & 0x0000FFFF) << 16;
- return swapped;
+ return swapHalfWords(Value, IsLittleEndian);
}
case ARM::fixup_arm_ldst_pcrel_12:
// ARM PC-relative values are offset by 8.
@@ -366,11 +392,8 @@ static unsigned adjustFixupValue(const M
// Same addressing mode as fixup_arm_pcrel_10,
// but with 16-bit halfwords swapped.
- if (Kind == ARM::fixup_t2_ldst_pcrel_12) {
- uint64_t swapped = (Value & 0xFFFF0000) >> 16;
- swapped |= (Value & 0x0000FFFF) << 16;
- return swapped;
- }
+ if (Kind == ARM::fixup_t2_ldst_pcrel_12)
+ return swapHalfWords(Value, IsLittleEndian);
return Value;
}
@@ -403,9 +426,7 @@ static unsigned adjustFixupValue(const M
out |= (Value & 0x700) << 4;
out |= (Value & 0x0FF);
- uint64_t swapped = (out & 0xFFFF0000) >> 16;
- swapped |= (out & 0x0000FFFF) << 16;
- return swapped;
+ return swapHalfWords(out, IsLittleEndian);
}
case ARM::fixup_arm_condbranch:
@@ -436,9 +457,7 @@ static unsigned adjustFixupValue(const M
out |= (Value & 0x1FF800) << 5; // imm6 field
out |= (Value & 0x0007FF); // imm11 field
- uint64_t swapped = (out & 0xFFFF0000) >> 16;
- swapped |= (out & 0x0000FFFF) << 16;
- return swapped;
+ return swapHalfWords(out, IsLittleEndian);
}
case ARM::fixup_t2_condbranch: {
Value = Value - 4;
@@ -451,9 +470,7 @@ static unsigned adjustFixupValue(const M
out |= (Value & 0x1F800) << 5; // imm6 field
out |= (Value & 0x007FF); // imm11 field
- uint32_t swapped = (out & 0xFFFF0000) >> 16;
- swapped |= (out & 0x0000FFFF) << 16;
- return swapped;
+ return swapHalfWords(out, IsLittleEndian);
}
case ARM::fixup_arm_thumb_bl: {
// The value doesn't encode the low bit (always zero) and is offset by
@@ -477,13 +494,10 @@ static unsigned adjustFixupValue(const M
uint32_t imm10Bits = (offset & 0x1FF800) >> 11;
uint32_t imm11Bits = (offset & 0x000007FF);
- uint32_t Binary = 0;
- uint32_t firstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10Bits);
- uint32_t secondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) |
+ uint32_t FirstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10Bits);
+ uint32_t SecondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) |
(uint16_t)imm11Bits);
- Binary |= secondHalf << 16;
- Binary |= firstHalf;
- return Binary;
+ return joinHalfWords(FirstHalf, SecondHalf, IsLittleEndian);
}
case ARM::fixup_arm_thumb_blx: {
// The value doesn't encode the low two bits (always zero) and is offset by
@@ -510,13 +524,10 @@ static unsigned adjustFixupValue(const M
uint32_t imm10HBits = (offset & 0xFFC00) >> 10;
uint32_t imm10LBits = (offset & 0x3FF);
- uint32_t Binary = 0;
- uint32_t firstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10HBits);
- uint32_t secondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) |
+ uint32_t FirstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10HBits);
+ uint32_t SecondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) |
((uint16_t)imm10LBits) << 1);
- Binary |= secondHalf << 16;
- Binary |= firstHalf;
- return Binary;
+ return joinHalfWords(FirstHalf, SecondHalf, IsLittleEndian);
}
case ARM::fixup_arm_thumb_cp:
// Offset by 4, and don't encode the low two bits. Two bytes of that
@@ -568,11 +579,8 @@ static unsigned adjustFixupValue(const M
// Same addressing mode as fixup_arm_pcrel_10, but with 16-bit halfwords
// swapped.
- if (Kind == ARM::fixup_t2_pcrel_10) {
- uint32_t swapped = (Value & 0xFFFF0000) >> 16;
- swapped |= (Value & 0x0000FFFF) << 16;
- return swapped;
- }
+ if (Kind == ARM::fixup_t2_pcrel_10)
+ return swapHalfWords(Value, IsLittleEndian);
return Value;
}
@@ -620,7 +628,8 @@ void ARMAsmBackend::processFixupValue(co
// Try to get the encoded value for the fixup as-if we're mapping it into
// the instruction. This allows adjustFixupValue() to issue a diagnostic
// if the value aren't invalid.
- (void)adjustFixupValue(Fixup, Value, false, &Asm.getContext());
+ (void)adjustFixupValue(Fixup, Value, false, &Asm.getContext(),
+ IsLittleEndian);
}
/// getFixupKindNumBytes - The number of bytes the fixup may change.
@@ -721,7 +730,7 @@ void ARMAsmBackend::applyFixup(const MCF
unsigned DataSize, uint64_t Value,
bool IsPCRel) const {
unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
- Value = adjustFixupValue(Fixup, Value, IsPCRel, nullptr);
+ Value = adjustFixupValue(Fixup, Value, IsPCRel, nullptr, IsLittleEndian);
if (!Value) return; // Doesn't change encoding.
unsigned Offset = Fixup.getOffset();
Added: llvm/trunk/test/MC/ARM/thumb2be-b.w-encoding.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ARM/thumb2be-b.w-encoding.s?rev=208076&view=auto
==============================================================================
--- llvm/trunk/test/MC/ARM/thumb2be-b.w-encoding.s (added)
+++ llvm/trunk/test/MC/ARM/thumb2be-b.w-encoding.s Tue May 6 05:05:11 2014
@@ -0,0 +1,12 @@
+// RUN: llvm-mc -triple=thumbv7-none-linux-gnueabi -mcpu=cortex-a8 -filetype=obj < %s | llvm-objdump -arch=thumb -s - | FileCheck %s --check-prefix=CHECK-LE
+// RUN: llvm-mc -triple=thumbebv7-none-linux-gnueabi -mcpu=cortex-a8 -filetype=obj < %s | llvm-objdump -arch=thumbeb -s - | FileCheck %s --check-prefix=CHECK-BE
+ .syntax unified
+ .code 16
+ .thumb_func
+foo:
+ b.w bar
+
+// CHECK-LE: Contents of section .text:
+// CHECK-LE-NEXT: 0000 fff7febf
+// CHECK-BE: Contents of section .text:
+// CHECK-BE-NEXT: 0000 f7ffbffe
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