Fix current_stack_pointer for LLVM #134
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Due to limitations of LLVM IR, clang cannot pin `sp` to `$r3` unless
`sp` is used by another line of inline assembly
(`asm volatile ("" : "=r" (sp))`).
When compiling with Clang, `os::current_stack_pointer` will return an
unexpected value (from a randomly assigned register).
This patch changes `os::current_stack_pointer` to use inline assembly to
obtain the stack pointer, which avoids the limitation of LLVM IR.
Thanks to Zixing Liu <[email protected]> for pointing out the reason
(GitHub @liushuyu).
Signed-off-by: Bingwu Zhang <[email protected]>
xtexx
changed the title
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Due to limitations of LLVM IR, clang cannot pin
spto$r3unlessspis used by another line of inline assembly(
asm volatile ("" : "=r" (sp))).When compiling with Clang,
os::current_stack_pointerwill return an unexpected value (from a randomly assigned register).This patch changes
os::current_stack_pointerto use inline assembly to obtain the stack pointer, which avoids the limitation of LLVM IR.Thanks to Zixing Liu [email protected] for pointing out the reason (GitHub @liushuyu).