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author | Tim Northover <Tim.Northover@arm.com> | 2013-05-04 20:14:09 +0000 |
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committer | Tim Northover <Tim.Northover@arm.com> | 2013-05-04 20:14:09 +0000 |
commit | 4a9b6b798d5ea335f5f29d278db83b830ae4a564 (patch) | |
tree | 5ee232d04df00a2f62837892d5d400addf0d578a /lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp | |
parent | 654c2d6b7a9274fc281c30c0e91419aadb6dc78a (diff) | |
download | external_llvm-4a9b6b798d5ea335f5f29d278db83b830ae4a564.zip external_llvm-4a9b6b798d5ea335f5f29d278db83b830ae4a564.tar.gz external_llvm-4a9b6b798d5ea335f5f29d278db83b830ae4a564.tar.bz2 |
AArch64: add stubs to support long function calls on MCJIT
As with global accesses, external functions could exist anywhere in
memory. Therefore the stub must create a complete 64-bit address. This
patch implements the fragment as (roughly):
movz x16, #:abs_g3:somefunc
movk x16, #:abs_g2_nc:somefunc
movk x16, #:abs_g1_nc:somefunc
movk x16, #:abs_g0_nc:somefunc
br x16
In principle we could save 4 bytes by using a literal-load instead,
but it is unclear that would be more efficient and can only be tested
when real hardware is readily available.
This allows (for example) the MCJIT test 2003-05-07-ArgumentTest to
pass on AArch64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181133 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp')
-rw-r--r-- | lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp index 14c0cd8..714eaf4 100644 --- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp +++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp @@ -336,7 +336,25 @@ void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE, } uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) { - if (Arch == Triple::arm) { + if (Arch == Triple::aarch64) { + // This stub has to be able to access the full address space, + // since symbol lookup won't necessarily find a handy, in-range, + // PLT stub for functions which could be anywhere. + uint32_t *StubAddr = (uint32_t*)Addr; + + // Stub can use ip0 (== x16) to calculate address + *StubAddr = 0xd2e00010; // movz ip0, #:abs_g3:<addr> + StubAddr++; + *StubAddr = 0xf2c00010; // movk ip0, #:abs_g2_nc:<addr> + StubAddr++; + *StubAddr = 0xf2a00010; // movk ip0, #:abs_g1_nc:<addr> + StubAddr++; + *StubAddr = 0xf2800010; // movk ip0, #:abs_g0_nc:<addr> + StubAddr++; + *StubAddr = 0xd61f0200; // br ip0 + + return Addr; + } else if (Arch == Triple::arm) { // TODO: There is only ARM far stub now. We should add the Thumb stub, // and stubs for branches Thumb - ARM and ARM - Thumb. uint32_t *StubAddr = (uint32_t*)Addr; |