forked from OSchip/llvm-project
7841e21c98
This patch introduces the new .bb_addr_map section feature which allows us to emit the bits needed for mapping binary profiles to basic blocks into a separate section. The format of the emitted data is represented as follows. It includes a header for every function: | Address of the function | -> 8 bytes (pointer size) | Number of basic blocks in this function (>0) | -> ULEB128 The header is followed by a BB record for every basic block. These records are ordered in the same order as MachineBasicBlocks are placed in the function. Each BB Info is structured as follows: | Offset of the basic block relative to function begin | -> ULEB128 | Binary size of the basic block | -> ULEB128 | BB metadata | -> ULEB128 [ MBB.isReturn() OR MBB.hasTailCall() << 1 OR MBB.isEHPad() << 2 ] The new feature will replace the existing "BB labels" functionality with -basic-block-sections=labels. The .bb_addr_map section scrubs the specially-encoded BB symbols from the binary and makes it friendly to profilers and debuggers. Furthermore, the new feature reduces the binary size overhead from 70% bloat to only 12%. For more information and results please refer to the RFC: https://lists.llvm.org/pipermail/llvm-dev/2020-July/143512.html Reviewed By: MaskRay, snehasish Differential Revision: https://reviews.llvm.org/D85408 |
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| .. | ||
| CMakeLists.txt | ||
| LLVMBuild.txt | ||
| MILexer.cpp | ||
| MILexer.h | ||
| MIParser.cpp | ||
| MIRParser.cpp | ||