Fix R_AARCH64_MOVW_UABS_G3 relocation

Summary: The relocation is missing mask so an address that has non-zero bits in 47:43 may overwrite the register number. (Frequently shows up as target register changed to `xzr`....)

Reviewers: t.p.northover, lhames

Subscribers: davide, aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D27609

llvm-svn: 289880

llvm/include/llvm/Object/ELFObjectFile.h

@@ -972,7 +972,7 @@ unsigned ELFObjectFile<ELFT>::getArch() const {
   case ELF::EM_X86_64:
     return Triple::x86_64;
   case ELF::EM_AARCH64:
-    return Triple::aarch64;
+    return IsLittleEndian ? Triple::aarch64 : Triple::aarch64_be;
   case ELF::EM_ARM:
     return Triple::arm;
   case ELF::EM_AVR:

llvm/include/llvm/Object/RelocVisitor.h

@@ -86,6 +86,7 @@ class RelocVisitor {
           return RelocToApply();
         }
       case Triple::aarch64:
+      case Triple::aarch64_be:
         switch (RelocType) {
         case llvm::ELF::R_AARCH64_ABS32:
           return visitELF_AARCH64_ABS32(R, Value);

llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

@@ -325,6 +325,8 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
   uint32_t *TargetPtr =
       reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
   uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
+  // Data should use target endian. Code should always use little endian.
+  bool isBE = Arch == Triple::aarch64_be;
 
   DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
                << format("%llx", Section.getAddressWithOffset(Offset))
@@ -340,119 +342,143 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
   case ELF::R_AARCH64_ABS64: {
     uint64_t *TargetPtr =
         reinterpret_cast<uint64_t *>(Section.getAddressWithOffset(Offset));
-    *TargetPtr = Value + Addend;
+    if (isBE)
+      support::ubig64_t::ref{TargetPtr} = Value + Addend;
+    else
+      support::ulittle64_t::ref{TargetPtr} = Value + Addend;
     break;
   }
   case ELF::R_AARCH64_PREL32: {
     uint64_t Result = Value + Addend - FinalAddress;
     assert(static_cast<int64_t>(Result) >= INT32_MIN &&
            static_cast<int64_t>(Result) <= UINT32_MAX);
-    *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU);
+    if (isBE)
+      support::ubig32_t::ref{TargetPtr} =
+        static_cast<uint32_t>(Result & 0xffffffffU);
+    else
+      support::ulittle32_t::ref{TargetPtr} =
+        static_cast<uint32_t>(Result & 0xffffffffU);
     break;
   }
   case ELF::R_AARCH64_CALL26: // fallthrough
   case ELF::R_AARCH64_JUMP26: {
     // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
     // calculation.
     uint64_t BranchImm = Value + Addend - FinalAddress;
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // "Check that -2^27 <= result < 2^27".
     assert(isInt<28>(BranchImm));
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0xfc000000U;
+    TargetValue &= 0xfc000000U;
     // Immediate goes in bits 25:0 of B and BL.
-    *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
+    TargetValue |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   case ELF::R_AARCH64_MOVW_UABS_G3: {
     uint64_t Result = Value + Addend;
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0xffe0001fU;
+    TargetValue &= 0xffe0001fU;
     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
-    *TargetPtr |= Result >> (48 - 5);
+    TargetValue |= ((Result & 0xffff000000000000ULL) >> (48 - 5));
     // Shift must be "lsl #48", in bits 22:21
-    assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation");
+    assert((TargetValue >> 21 & 0x3) == 3 && "invalid shift for relocation");
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   case ELF::R_AARCH64_MOVW_UABS_G2_NC: {
     uint64_t Result = Value + Addend;
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0xffe0001fU;
+    TargetValue &= 0xffe0001fU;
     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
-    *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5));
+    TargetValue |= ((Result & 0xffff00000000ULL) >> (32 - 5));
     // Shift must be "lsl #32", in bits 22:21
-    assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation");
+    assert((TargetValue >> 21 & 0x3) == 2 && "invalid shift for relocation");
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   case ELF::R_AARCH64_MOVW_UABS_G1_NC: {
     uint64_t Result = Value + Addend;
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0xffe0001fU;
+    TargetValue &= 0xffe0001fU;
     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
-    *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5));
+    TargetValue |= ((Result & 0xffff0000U) >> (16 - 5));
     // Shift must be "lsl #16", in bits 22:2
-    assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation");
+    assert((TargetValue >> 21 & 0x3) == 1 && "invalid shift for relocation");
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   case ELF::R_AARCH64_MOVW_UABS_G0_NC: {
     uint64_t Result = Value + Addend;
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0xffe0001fU;
+    TargetValue &= 0xffe0001fU;
     // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
-    *TargetPtr |= ((Result & 0xffffU) << 5);
+    TargetValue |= ((Result & 0xffffU) << 5);
     // Shift must be "lsl #0", in bits 22:21.
-    assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation");
+    assert((TargetValue >> 21 & 0x3) == 0 && "invalid shift for relocation");
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
     // Operation: Page(S+A) - Page(P)
     uint64_t Result =
         ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // Check that -2^32 <= X < 2^32
     assert(isInt<33>(Result) && "overflow check failed for relocation");
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0x9f00001fU;
+    TargetValue &= 0x9f00001fU;
     // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
     // from bits 32:12 of X.
-    *TargetPtr |= ((Result & 0x3000U) << (29 - 12));
-    *TargetPtr |= ((Result & 0x1ffffc000ULL) >> (14 - 5));
+    TargetValue |= ((Result & 0x3000U) << (29 - 12));
+    TargetValue |= ((Result & 0x1ffffc000ULL) >> (14 - 5));
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   case ELF::R_AARCH64_LDST32_ABS_LO12_NC: {
     // Operation: S + A
     uint64_t Result = Value + Addend;
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0xffc003ffU;
+    TargetValue &= 0xffc003ffU;
     // Immediate goes in bits 21:10 of LD/ST instruction, taken
     // from bits 11:2 of X
-    *TargetPtr |= ((Result & 0xffc) << (10 - 2));
+    TargetValue |= ((Result & 0xffc) << (10 - 2));
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   case ELF::R_AARCH64_LDST64_ABS_LO12_NC: {
     // Operation: S + A
     uint64_t Result = Value + Addend;
+    uint32_t TargetValue = support::ulittle32_t::ref{TargetPtr};
 
     // AArch64 code is emitted with .rela relocations. The data already in any
     // bits affected by the relocation on entry is garbage.
-    *TargetPtr &= 0xffc003ffU;
+    TargetValue &= 0xffc003ffU;
     // Immediate goes in bits 21:10 of LD/ST instruction, taken
     // from bits 11:3 of X
-    *TargetPtr |= ((Result & 0xff8) << (10 - 3));
+    TargetValue |= ((Result & 0xff8) << (10 - 3));
+    support::ulittle32_t::ref{TargetPtr} = TargetValue;
     break;
   }
   }

llvm/test/ExecutionEngine/RuntimeDyld/AArch64/ELF_ARM64_BE-relocations.s

@@ -0,0 +1,34 @@
+# RUN: llvm-mc -triple=aarch64_be-none-linux-gnu -filetype=obj -o %T/be-reloc.o %s
+# RUN: llvm-rtdyld -triple=aarch64_be-none-linux-gnu -verify -dummy-extern f=0x0123456789abcdef -check=%s %T/be-reloc.o
+
+        .text
+        .globl  g
+        .p2align        2
+        .type   g,@function
+g:
+# R_AARCH64_MOVW_UABS_G3
+        movz    x0, #:abs_g3:f
+# R_AARCH64_MOVW_UABS_G2_NC
+        movk    x0, #:abs_g2_nc:f
+# R_AARCH64_MOVW_UABS_G1_NC
+        movk    x0, #:abs_g1_nc:f
+# R_AARCH64_MOVW_UABS_G0_NC
+        movk    x0, #:abs_g0_nc:f
+        ret
+        .Lfunc_end0:
+        .size   g, .Lfunc_end0-g
+
+        .type   k,@object
+        .data
+        .globl  k
+        .p2align        3
+k:
+        .xword  f
+        .size   k, 8
+
+# LE instructions read as BE
+# rtdyld-check: *{4}(g) = 0x6024e0d2
+# rtdyld-check: *{4}(g + 4) = 0xe0acc8f2
+# rtdyld-check: *{4}(g + 8) = 0x6035b1f2
+# rtdyld-check: *{4}(g + 12) = 0xe0bd99f2
+# rtdyld-check: *{8}k = f

llvm/test/ExecutionEngine/RuntimeDyld/AArch64/ELF_ARM64_relocations.s

@@ -0,0 +1,33 @@
+# RUN: llvm-mc -triple=arm64-none-linux-gnu -filetype=obj -o %T/reloc.o %s
+# RUN: llvm-rtdyld -triple=arm64-none-linux-gnu -verify -dummy-extern f=0x0123456789abcdef -check=%s %T/reloc.o
+
+        .text
+        .globl  g
+        .p2align        2
+        .type   g,@function
+g:
+# R_AARCH64_MOVW_UABS_G3
+        movz    x0, #:abs_g3:f
+# R_AARCH64_MOVW_UABS_G2_NC
+        movk    x0, #:abs_g2_nc:f
+# R_AARCH64_MOVW_UABS_G1_NC
+        movk    x0, #:abs_g1_nc:f
+# R_AARCH64_MOVW_UABS_G0_NC
+        movk    x0, #:abs_g0_nc:f
+        ret
+        .Lfunc_end0:
+        .size   g, .Lfunc_end0-g
+
+        .type   k,@object
+        .data
+        .globl  k
+        .p2align        3
+k:
+        .xword  f
+        .size   k, 8
+
+# rtdyld-check: *{4}(g) = 0xd2e02460
+# rtdyld-check: *{4}(g + 4) = 0xf2c8ace0
+# rtdyld-check: *{4}(g + 8) = 0xf2b13560
+# rtdyld-check: *{4}(g + 12) = 0xf299bde0
+# rtdyld-check: *{8}k = f