From 675b9e9f3d567bdf1a31ce9d9ce2451ae09dc9fa Mon Sep 17 00:00:00 2001 From: Tim Northover Date: Sun, 19 May 2013 15:39:03 +0000 Subject: AArch64: make RuntimeDyld relocations idempotent AArch64 ELF uses .rela relocations so there's no need to actually make use of the bits we're setting in the destination However, we should make sure all bits are cleared properly since multiple runs of resolveRelocations are possible and these could combine to produce invalid results if stale versions remain in the code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182214 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp | 24 ++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) (limited to 'lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp') diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp index 2773bf1e19..9494e6b44e 100644 --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp @@ -277,7 +277,6 @@ void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, } } -// FIXME: PR16013: this routine needs modification to handle repeated relocations. void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, uint64_t Offset, uint64_t Value, @@ -303,7 +302,7 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, *TargetPtr = Value + Addend; break; } - case ELF::R_AARCH64_PREL32: { // test-shift.ll (.eh_frame) + case ELF::R_AARCH64_PREL32: { uint64_t Result = Value + Addend - FinalAddress; assert(static_cast(Result) >= INT32_MIN && static_cast(Result) <= UINT32_MAX); @@ -319,12 +318,20 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, // "Check that -2^27 <= result < 2^27". assert(-(1LL << 27) <= static_cast(BranchImm) && static_cast(BranchImm) < (1LL << 27)); + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xfc000000U; // Immediate goes in bits 25:0 of B and BL. *TargetPtr |= static_cast(BranchImm & 0xffffffcU) >> 2; break; } case ELF::R_AARCH64_MOVW_UABS_G3: { uint64_t Result = Value + Addend; + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xff80001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= Result >> (48 - 5); // Shift is "lsl #48", in bits 22:21 @@ -333,6 +340,11 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, } case ELF::R_AARCH64_MOVW_UABS_G2_NC: { uint64_t Result = Value + Addend; + + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xff80001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5)); // Shift is "lsl #32", in bits 22:21 @@ -341,6 +353,10 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, } case ELF::R_AARCH64_MOVW_UABS_G1_NC: { uint64_t Result = Value + Addend; + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xff80001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5)); // Shift is "lsl #16", in bits 22:21 @@ -349,6 +365,10 @@ void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, } case ELF::R_AARCH64_MOVW_UABS_G0_NC: { uint64_t Result = Value + Addend; + + // AArch64 code is emitted with .rela relocations. The data already in any + // bits affected by the relocation on entry is garbage. + *TargetPtr &= 0xff80001fU; // Immediate goes in bits 20:5 of MOVZ/MOVK instruction *TargetPtr |= ((Result & 0xffffU) << 5); // Shift is "lsl #0", in bits 22:21. No action needed. -- cgit v1.2.3