[llvm-branch-commits] [llvm] 79cac55 - Fix unwind info relocation with large code model on AArch64

[Tom Stellard via llvm-branch-commits]

Author: Valentin Churavy
Date: 2020-12-08T16:10:47-05:00
New Revision: 79cac55bf044bd8502f54076816a942388e3eae0

URL: https://github.com/llvm/llvm-project/commit/79cac55bf044bd8502f54076816a942388e3eae0
DIFF: https://github.com/llvm/llvm-project/commit/79cac55bf044bd8502f54076816a942388e3eae0.diff

LOG: Fix unwind info relocation with large code model on AArch64

Makes sure that the unwind info uses 64bits pcrel relocation if a large code model is specified and handle the corresponding relocation in the ExecutionEngine. This can happen with certain kernel configuration (the same as the one in https://reviews.llvm.org/D27609, found at least on the ArchLinux stock kernel and the one used on https://www.packet.net/) using the builtin JIT memory manager.

Co-authored-by: Yichao Yu <yyc1992 at gmail.com>

Differential Revision: https://reviews.llvm.org/D27629

(cherry picked from commit 18805ea951be02fcab6e7b11c3c7d929bcf1441a)

Added: 
    llvm/test/MC/AArch64/ELF_ARM64_large-relocations.s

Modified: 
    llvm/lib/MC/MCObjectFileInfo.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index b77a9635f64c..b9b4416fde21 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -317,6 +317,8 @@ void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
     break;
   case Triple::ppc64:
   case Triple::ppc64le:
+  case Triple::aarch64:
+  case Triple::aarch64_be:
   case Triple::x86_64:
     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
                      (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);

diff  --git a/llvm/test/MC/AArch64/ELF_ARM64_large-relocations.s b/llvm/test/MC/AArch64/ELF_ARM64_large-relocations.s
new file mode 100644
index 000000000000..66f28dabd79f
--- /dev/null
+++ b/llvm/test/MC/AArch64/ELF_ARM64_large-relocations.s
@@ -0,0 +1,20 @@
+# RUN: llvm-mc -triple=arm64-none-linux-gnu -large-code-model -filetype=obj -o %T/large-reloc.o %s
+# RUN: llvm-rtdyld -triple=arm64-none-linux-gnu -verify -map-section large-reloc.o,.eh_frame=0x10000 -map-section large-reloc.o,.text=0xffff000000000000 -check=%s %T/large-reloc.o
+# RUN-BE: llvm-mc -triple=aarch64_be-none-linux-gnu -large-code-model -filetype=obj -o %T/be-large-reloc.o %s
+# RUN-BE: llvm-rtdyld -triple=aarch64_be-none-linux-gnu -verify -map-section be-large-reloc.o,.eh_frame=0x10000 -map-section be-large-reloc.o,.text=0xffff000000000000 -check=%s %T/be-large-reloc.o
+
+        .text
+        .globl  g
+        .p2align        2
+        .type   g, at function
+g:
+        .cfi_startproc
+        mov      x0, xzr
+        ret
+        .Lfunc_end0:
+        .size   g, .Lfunc_end0-g
+        .cfi_endproc
+
+# Skip the CIE and load the 8 bytes PC begin pointer.
+# Assuming the CIE and the FDE length are both 4 bytes.
+# rtdyld-check: *{8}(section_addr(large-reloc.o, .eh_frame) + (*{4}(section_addr(large-reloc.o, .eh_frame))) + 0xc) = g - (section_addr(large-reloc.o, .eh_frame) + (*{4}(section_addr(large-reloc.o, .eh_frame))) + 0xc)