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Diffstat (limited to 'docs/BitCodeFormat.rst')
| -rw-r--r-- | docs/BitCodeFormat.rst | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/docs/BitCodeFormat.rst b/docs/BitCodeFormat.rst index a9a123595f7f..6ee3842c8d90 100644 --- a/docs/BitCodeFormat.rst +++ b/docs/BitCodeFormat.rst @@ -550,6 +550,8 @@ LLVM IR is defined with the following blocks: * 17 --- `TYPE_BLOCK`_ --- This describes all of the types in the module. +* 23 --- `STRTAB_BLOCK`_ --- The bitcode file's string table. + .. _MODULE_BLOCK: MODULE_BLOCK Contents @@ -577,7 +579,7 @@ MODULE_CODE_VERSION Record ``[VERSION, version#]`` The ``VERSION`` record (code 1) contains a single value indicating the format -version. Versions 0 and 1 are supported at this time. The difference between +version. Versions 0, 1 and 2 are supported at this time. The difference between version 0 and 1 is in the encoding of instruction operands in each `FUNCTION_BLOCK`_. @@ -620,6 +622,12 @@ as unsigned VBRs. However, forward references are rare, except in the case of phi instructions. For phi instructions, operands are encoded as `Signed VBRs`_ to deal with forward references. +In version 2, the meaning of module records ``FUNCTION``, ``GLOBALVAR``, +``ALIAS``, ``IFUNC`` and ``COMDAT`` change such that the first two operands +specify an offset and size of a string in a string table (see `STRTAB_BLOCK +Contents`_), the function name is removed from the ``FNENTRY`` record in the +value symbol table, and the top-level ``VALUE_SYMTAB_BLOCK`` may only contain +``FNENTRY`` records. MODULE_CODE_TRIPLE Record ^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -673,11 +681,14 @@ for each library name referenced. MODULE_CODE_GLOBALVAR Record ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -``[GLOBALVAR, pointer type, isconst, initid, linkage, alignment, section, visibility, threadlocal, unnamed_addr, externally_initialized, dllstorageclass, comdat]`` +``[GLOBALVAR, strtab offset, strtab size, pointer type, isconst, initid, linkage, alignment, section, visibility, threadlocal, unnamed_addr, externally_initialized, dllstorageclass, comdat]`` The ``GLOBALVAR`` record (code 7) marks the declaration or definition of a global variable. The operand fields are: +* *strtab offset*, *strtab size*: Specifies the name of the global variable. + See `STRTAB_BLOCK Contents`_. + * *pointer type*: The type index of the pointer type used to point to this global variable @@ -755,11 +766,14 @@ global variable. The operand fields are: MODULE_CODE_FUNCTION Record ^^^^^^^^^^^^^^^^^^^^^^^^^^^ -``[FUNCTION, type, callingconv, isproto, linkage, paramattr, alignment, section, visibility, gc, prologuedata, dllstorageclass, comdat, prefixdata, personalityfn]`` +``[FUNCTION, strtab offset, strtab size, type, callingconv, isproto, linkage, paramattr, alignment, section, visibility, gc, prologuedata, dllstorageclass, comdat, prefixdata, personalityfn]`` The ``FUNCTION`` record (code 8) marks the declaration or definition of a function. The operand fields are: +* *strtab offset*, *strtab size*: Specifies the name of the function. + See `STRTAB_BLOCK Contents`_. + * *type*: The type index of the function type describing this function * *callingconv*: The calling convention number: @@ -817,11 +831,14 @@ function. The operand fields are: MODULE_CODE_ALIAS Record ^^^^^^^^^^^^^^^^^^^^^^^^ -``[ALIAS, alias type, aliasee val#, linkage, visibility, dllstorageclass, threadlocal, unnamed_addr]`` +``[ALIAS, strtab offset, strtab size, alias type, aliasee val#, linkage, visibility, dllstorageclass, threadlocal, unnamed_addr]`` The ``ALIAS`` record (code 9) marks the definition of an alias. The operand fields are +* *strtab offset*, *strtab size*: Specifies the name of the alias. + See `STRTAB_BLOCK Contents`_. + * *alias type*: The type index of the alias * *aliasee val#*: The value index of the aliased value @@ -1300,3 +1317,20 @@ METADATA_ATTACHMENT Contents ---------------------------- The ``METADATA_ATTACHMENT`` block (id 16) ... + +.. _STRTAB_BLOCK: + +STRTAB_BLOCK Contents +--------------------- + +The ``STRTAB`` block (id 23) contains a single record (``STRTAB_BLOB``, id 1) +with a single blob operand containing the bitcode file's string table. + +Strings in the string table are not null terminated. A record's *strtab +offset* and *strtab size* operands specify the byte offset and size of a +string within the string table. + +The string table is used by all preceding blocks in the bitcode file that are +not succeeded by another intervening ``STRTAB`` block. Normally a bitcode +file will have a single string table, but it may have more than one if it +was created by binary concatenation of multiple bitcode files. |