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[WebAssembly] Initial implementation of PIC code generation
Audit Required492f752969ff

Authored by sbc100 on Mar 26 2019, 12:46 PM.

Description

[WebAssembly] Initial implementation of PIC code generation

This change implements lowering of references global symbols in PIC
mode.

This change implements lowering of global references in PIC mode using a
new @GOT reference type. @GOT references can be used with function or
data symbol names combined with the get_global instruction. In this case
the linker will insert the wasm global that stores the address of the
symbol (either in memory for data symbols or in the wasm table for
function symbols).

For now I'm continuing to use the R_WASM_GLOBAL_INDEX_LEB relocation
type for this type of reference which means that this relocation type
can refer to either a global or a function or data symbol. We could
choose to introduce specific relocation types for GOT entries in the
future. See the current dynamic linking proposal:

https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md

Differential Revision: https://reviews.llvm.org/D54647

llvm-svn: 357022

Details

Auditors
grosbach
Committed
sbc100Mar 26 2019, 12:46 PM
Differential Revision
D54647: [WebAssembly] Initial implementation of PIC code generation
Parents
rG6f4c45e9fc70: gn build: Format all build files
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