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[PowerPC] fix broken JIT-compiled code with tail call optimization

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The relocation for branch instructions in the dynamic loader of ExecutionEngine assumes branch instructions with R_PPC64_REL24 relocation type are only bl. However, with the tail call optimization, b instructions can be also used to jump into another function.
This patch makes the relocation to keep bits in the branch instruction other than the jump offset to avoid relocation rewrites a b instruction into bl.

Differential Revision: https://reviews.llvm.org/D47456



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333502 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hiroshi Inoue 2018-05-30 04:48:29 +00:00
parent 4548453c8b
commit 9066b8af33
2 changed files with 51 additions and 2 deletions
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5
lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
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@ -772,8 +772,9 @@ void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend);
if (SignExtend64<26>(delta) != delta)
llvm_unreachable("Relocation R_PPC64_REL24 overflow");
// Generates a 'bl <address>' instruction
writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
// We preserve bits other than LI field, i.e. PO and AA/LK fields.
uint32_t Inst = readBytesUnaligned(LocalAddress, 4);
writeInt32BE(LocalAddress, (Inst & 0xFC000003) | (delta & 0x03FFFFFC));
} break;
case ELF::R_PPC64_REL32: {
uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);

48
test/ExecutionEngine/RuntimeDyld/PowerPC/ppc64_reloc.s Normal file
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@ -0,0 +1,48 @@
# test for little endian
# RUN: rm -rf %t && mkdir -p %t
# RUN: llvm-mc -triple=powerpc64le-unknown-linux-gnu -filetype=obj -o %t/ppc64_reloc.o %s
# RUN: llvm-mc -triple=powerpc64le-unknown-linux-gnu -filetype=obj -o %t/ppc64_elf_module_b.o %S/Inputs/ppc64_elf_module_b.s
# RUN: llvm-rtdyld -triple=powerpc64le-unknown-linux-gnu -verify -check=%s %t/ppc64_reloc.o %t/ppc64_elf_module_b.o
# test for big endian
# RUN: rm -rf %t && mkdir -p %t
# RUN: llvm-mc -triple=powerpc64-unknown-linux-gnu -filetype=obj -o %t/ppc64_reloc.o %s
# RUN: llvm-mc -triple=powerpc64-unknown-linux-gnu -filetype=obj -o %t/ppc64_elf_module_b.o %S/Inputs/ppc64_elf_module_b.s
# RUN: llvm-rtdyld -triple=powerpc64-unknown-linux-gnu -verify -check=%s %t/ppc64_reloc.o %t/ppc64_elf_module_b.o
.text
.abiversion 2
.file "test.c"
.globl func
.p2align 4
.type func,@function
func: # @func
.Lfunc_begin0:
.Lfunc_gep0:
addis 2, 12, .TOC.-.Lfunc_gep0@ha
addi 2, 2, .TOC.-.Lfunc_gep0@l
.Lfunc_lep0:
.localentry func, .Lfunc_lep0-.Lfunc_gep0
mflr 0
std 31, -8(1)
std 0, 16(1)
stdu 1, -112(1)
mr 31, 1
# confirm that LK flag is set for bl
# rtdyld-check: (*{4}call_bl) & 1 = 1
call_bl:
bl foo
nop
li 3, 0
addi 1, 1, 112
ld 0, 16(1)
ld 31, -8(1)
mtlr 0
# confirm that LK flag is not set for b
# rtdyld-check: (*{4}call_b) & 1 = 0
call_b:
b foo
.long 0
.quad 0
.Lfunc_end0:
.size func, .Lfunc_end0-.Lfunc_begin0