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| -rw-r--r-- | docs/PNaClLangRef.rst | 43 |
1 files changed, 38 insertions, 5 deletions
diff --git a/docs/PNaClLangRef.rst b/docs/PNaClLangRef.rst index 8ddfae0739..4ba5c5ff21 100644 --- a/docs/PNaClLangRef.rst +++ b/docs/PNaClLangRef.rst @@ -372,18 +372,26 @@ The only intrinsics supported by PNaCl bitcode are the following. * ``llvm.stacksave`` * ``llvm.stackrestore`` + + These intrinsics are used to implement language features like scoped automatic + variable sized arrays in C99. ``llvm.stacksave`` returns a value that + represents the current state of the stack. This value may only be used as the + argument to ``llvm.stackrestore``, which restores the stack to the given + state. + * ``llvm.trap`` -* ``llvm.nacl.read.tp`` - TODO: describe + This intrinsic is lowered to a target dependent trap instruction, which aborts + execution. -* ``llvm.nacl.longjmp`` +* ``llvm.nacl.read.tp`` - TODO: describe + See :ref:`thread pointer related intrinsics <threadpointerintrinsics>`. +* ``llvm.nacl.longjmp`` * ``llvm.nacl.setjmp`` - TODO: describe + See :ref:`Setjmp and Longjmp <setjmplongjmp>`. .. _atomic intrinsics: @@ -395,6 +403,31 @@ The only intrinsics supported by PNaCl bitcode are the following. See :ref:`atomic intrinsics <atomicintrinsics>`. +.. _threadpointerintrinsics: + +Thread pointer related intrinsics +--------------------------------- + +.. code-block:: llvm + + declare i8* @llvm.nacl.read.tp() + +Returns the thread pointer, which can be set by the embedding sandbox's runtime. + +.. _setjmplongjmp: + +Setjmp and Longjmp +------------------ + +.. code-block:: llvm + + declare void @llvm.nacl.longjmp(i8* %jmpbuf, i32) + declare i32 @llvm.nacl.setjmp(i8* %jmpbuf) + +These intrinsics implement the semantics of C11 ``setjmp`` and ``longjmp``. The +``jmpbuf`` pointer must be 64-bit aligned and point to at least 1024 bytes of +allocated memory. + .. _atomicintrinsics: Atomic intrinsics |