Completed :lower16: / :upper16: support for movw / movt pairs on Darwin.
- Fixed :upper16: fix up routine. It should be shifting down the top 16 bits first.
- Added support for Thumb2 :lower16: and :upper16: fix up.
- Added :upper16: and :lower16: relocation support to mach-o object writer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123424 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index e7a9174..aa0178e 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -656,10 +656,10 @@
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
+ unsigned Log2Size,
uint64_t &FixedValue) {
uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
unsigned IsPCRel = isFixupKindPCRel(Asm, Fixup.getKind());
- unsigned Log2Size = getFixupKindLog2Size(Fixup.getKind());
unsigned Type = macho::RIT_Vanilla;
// See <reloc.h>.
@@ -720,10 +720,10 @@
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
+ unsigned Log2Size,
uint64_t &FixedValue) {
uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
unsigned IsPCRel = isFixupKindPCRel(Asm, Fixup.getKind());
- unsigned Log2Size = getFixupKindLog2Size(Fixup.getKind());
unsigned Type = macho::RIT_Vanilla;
// See <reloc.h>.
@@ -775,6 +775,100 @@
Relocations[Fragment->getParent()].push_back(MRE);
}
+ void RecordARMMovwMovtRelocation(const MCAssembler &Asm,
+ const MCAsmLayout &Layout,
+ const MCFragment *Fragment,
+ const MCFixup &Fixup, MCValue Target,
+ uint64_t &FixedValue) {
+ uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
+ unsigned IsPCRel = isFixupKindPCRel(Asm, Fixup.getKind());
+ unsigned Type = macho::RIT_ARM_Half;
+
+ // See <reloc.h>.
+ const MCSymbol *A = &Target.getSymA()->getSymbol();
+ MCSymbolData *A_SD = &Asm.getSymbolData(*A);
+
+ if (!A_SD->getFragment())
+ report_fatal_error("symbol '" + A->getName() +
+ "' can not be undefined in a subtraction expression");
+
+ uint32_t Value = getSymbolAddress(A_SD, Layout);
+ uint32_t Value2 = 0;
+ uint64_t SecAddr = getSectionAddress(A_SD->getFragment()->getParent());
+ FixedValue += SecAddr;
+
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ MCSymbolData *B_SD = &Asm.getSymbolData(B->getSymbol());
+
+ if (!B_SD->getFragment())
+ report_fatal_error("symbol '" + B->getSymbol().getName() +
+ "' can not be undefined in a subtraction expression");
+
+ // Select the appropriate difference relocation type.
+ Type = macho::RIT_ARM_HalfDifference;
+ Value2 = getSymbolAddress(B_SD, Layout);
+ FixedValue -= getSectionAddress(B_SD->getFragment()->getParent());
+ }
+
+ // Relocations are written out in reverse order, so the PAIR comes first.
+ // ARM_RELOC_HALF and ARM_RELOC_HALF_SECTDIFF abuse the r_length field:
+ //
+ // For these two r_type relocations they always have a pair following them
+ // and the r_length bits are used differently. The encoding of the
+ // r_length is as follows:
+ // low bit of r_length:
+ // 0 - :lower16: for movw instructions
+ // 1 - :upper16: for movt instructions
+ // high bit of r_length:
+ // 0 - arm instructions
+ // 1 - thumb instructions
+ // the other half of the relocated expression is in the following pair
+ // relocation entry in the the low 16 bits of r_address field.
+ unsigned ThumbBit = 0;
+ unsigned MovtBit = 0;
+ switch (Fixup.getKind()) {
+ default: break;
+ case ARM::fixup_arm_movt_hi16:
+ case ARM::fixup_arm_movt_hi16_pcrel:
+ MovtBit = 1;
+ break;
+ case ARM::fixup_t2_movt_hi16:
+ case ARM::fixup_t2_movt_hi16_pcrel:
+ MovtBit = 1;
+ // Fallthrough
+ case ARM::fixup_t2_movw_lo16:
+ case ARM::fixup_t2_movw_lo16_pcrel:
+ ThumbBit = 1;
+ break;
+ }
+
+
+ if (Type == macho::RIT_ARM_HalfDifference) {
+ uint32_t OtherHalf = MovtBit
+ ? (FixedValue & 0xffff) : ((FixedValue & 0xffff0000) >> 16);
+
+ macho::RelocationEntry MRE;
+ MRE.Word0 = ((OtherHalf << 0) |
+ (macho::RIT_Pair << 24) |
+ (MovtBit << 28) |
+ (ThumbBit << 29) |
+ (IsPCRel << 30) |
+ macho::RF_Scattered);
+ MRE.Word1 = Value2;
+ Relocations[Fragment->getParent()].push_back(MRE);
+ }
+
+ macho::RelocationEntry MRE;
+ MRE.Word0 = ((FixupOffset << 0) |
+ (Type << 24) |
+ (MovtBit << 28) |
+ (ThumbBit << 29) |
+ (IsPCRel << 30) |
+ macho::RF_Scattered);
+ MRE.Word1 = Value;
+ Relocations[Fragment->getParent()].push_back(MRE);
+ }
+
void RecordTLVPRelocation(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
@@ -868,6 +962,24 @@
// Report as 'long', even though that is not quite accurate.
Log2Size = llvm::Log2_32(4);
return true;
+
+ case ARM::fixup_arm_movt_hi16:
+ case ARM::fixup_arm_movt_hi16_pcrel:
+ case ARM::fixup_t2_movt_hi16:
+ case ARM::fixup_t2_movt_hi16_pcrel:
+ RelocType = unsigned(macho::RIT_ARM_HalfDifference);
+ // Report as 'long', even though that is not quite accurate.
+ Log2Size = llvm::Log2_32(4);
+ return true;
+
+ case ARM::fixup_arm_movw_lo16:
+ case ARM::fixup_arm_movw_lo16_pcrel:
+ case ARM::fixup_t2_movw_lo16:
+ case ARM::fixup_t2_movw_lo16_pcrel:
+ RelocType = unsigned(macho::RIT_ARM_Half);
+ // Report as 'long', even though that is not quite accurate.
+ Log2Size = llvm::Log2_32(4);
+ return true;
}
}
void RecordARMRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
@@ -884,9 +996,14 @@
// If this is a difference or a defined symbol plus an offset, then we need
// a scattered relocation entry. Differences always require scattered
// relocations.
- if (Target.getSymB())
- return RecordARMScatteredRelocation(Asm, Layout, Fragment, Fixup,
- Target, FixedValue);
+ if (Target.getSymB()) {
+ if (RelocType == macho::RIT_ARM_Half ||
+ RelocType == macho::RIT_ARM_HalfDifference)
+ return RecordARMMovwMovtRelocation(Asm, Layout, Fragment, Fixup,
+ Target, FixedValue);
+ return RecordARMScatteredRelocation(Asm, Layout, Fragment, Fixup,
+ Target, Log2Size, FixedValue);
+ }
// Get the symbol data, if any.
MCSymbolData *SD = 0;
@@ -902,8 +1019,8 @@
if (IsPCRel && RelocType == macho::RIT_Vanilla)
Offset += 1 << Log2Size;
if (Offset && SD && !doesSymbolRequireExternRelocation(SD))
- return RecordARMScatteredRelocation(Asm, Layout, Fragment, Fixup,
- Target, FixedValue);
+ return RecordARMScatteredRelocation(Asm, Layout, Fragment, Fixup, Target,
+ Log2Size, FixedValue);
// See <reloc.h>.
uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();
@@ -986,7 +1103,7 @@
// Differences always require scattered relocations.
if (Target.getSymB())
return RecordScatteredRelocation(Asm, Layout, Fragment, Fixup,
- Target, FixedValue);
+ Target, Log2Size, FixedValue);
// Get the symbol data, if any.
MCSymbolData *SD = 0;
@@ -1000,7 +1117,7 @@
Offset += 1 << Log2Size;
if (Offset && SD && !doesSymbolRequireExternRelocation(SD))
return RecordScatteredRelocation(Asm, Layout, Fragment, Fixup,
- Target, FixedValue);
+ Target, Log2Size, FixedValue);
// See <reloc.h>.
uint32_t FixupOffset = Layout.getFragmentOffset(Fragment)+Fixup.getOffset();