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Diffstat (limited to 'llvm/docs/Extensions.rst')
| -rw-r--r-- | llvm/docs/Extensions.rst | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/llvm/docs/Extensions.rst b/llvm/docs/Extensions.rst index 214323e..91a3ac0 100644 --- a/llvm/docs/Extensions.rst +++ b/llvm/docs/Extensions.rst @@ -416,7 +416,36 @@ as offsets relative to prior addresses. The following versioning schemes are currently supported (newer versions support features of the older versions). -Version 3 (newest): Capable of encoding callsite offsets. Enabled by the 6th bit +Version 4 (newest): Capable of encoding basic block hashes. This feature is +enabled by the 7th bit of the feature byte. + +Example: + +.. code-block:: gas + + .section ".llvm_bb_addr_map","",@llvm_bb_addr_map + .byte 4 # version number + .byte 96 # feature byte + .quad .Lfunc_begin0 # address of the function + .byte 2 # number of basic blocks + # BB record for BB_0 + .byte 0 # BB_0 ID + .uleb128 .Lfunc_begin0-.Lfunc_begin0 # BB_0 offset relative to function entry (always zero) + .byte 0 # number of callsites in this block + .uleb128 .LBB_END0_0-.Lfunc_begin0 # BB_0 size + .byte x # BB_0 metadata + .quad 9080480745856761856 # BB_0 hash + # BB record for BB_1 + .byte 1 # BB_1 ID + .uleb128 .LBB0_1-.LBB_END0_0 # BB_1 offset relative to the end of last block (BB_0). + .byte 2 # number of callsites in this block + .uleb128 .LBB0_1_CS0-.LBB0_1 # offset of callsite end relative to the previous offset (.LBB0_1) + .uleb128 .LBB0_1_CS1-.LBB0_1_CS0 # offset of callsite end relative to the previous offset (.LBB0_1_CS0) + .uleb128 .LBB_END0_1-.LBB0_1_CS1 # BB_1 size offset (Offset of the block end relative to the previous offset). + .byte y # BB_1 metadata + .quad 2363478788702666771 # BB_1 hash + +Version 3: Capable of encoding callsite offsets. Enabled by the 6th bit of the feature byte. Example: |