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MIPS ABI states that every function must be called through jalr $t9. In other words, a function expect that t9 register points to the beginning of its code. A function uses this register to calculate offset to the Global Offset Table and save it to the `gp` register. ``` lui $gp, %hi(_gp_disp) addiu $gp, %lo(_gp_disp) addu $gp, $gp, $t9 ``` If `t9` and as a result `$gp` point to the wrong place the following code loads incorrect value from GOT and passes control to invalid code. ``` lw $v0,%call16(foo)($gp) jalr $t9 ``` OrcMips32 and OrcMips64 writeResolverCode methods pass control to the resolved address, but do not setup `$t9` before the call. The `t9` holds value of the beginning of `resolver` code so any attempts to call routines via GOT failed. This change fixes the problem. The `OrcLazy/hidden-visibility.ll` test starts to pass correctly. Before the change it fails on MIPS because the `exitOnLazyCallThroughFailure` called from the resolver code could not call libc routine `exit` via GOT. Differential Revision: http://reviews.llvm.org/D56058 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351000 91177308-0d34-0410-b5e6-96231b3b80d8
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