Author: antangelo Date: 2023-09-17T01:26:26-04:00 New Revision: da35b2e57a164ec62278f1685d0c684c5bc2d666
URL: https://github.com/llvm/llvm-project/commit/da35b2e57a164ec62278f1685d0c684c5bc2d666 DIFF: https://github.com/llvm/llvm-project/commit/da35b2e57a164ec62278f1685d0c684c5bc2d666.diff LOG: [clang][Docs] Document X86 interrupt attribute (#65662) Adds documentation for the X86 `__attribute__((interrupt))` attribute, in a similar format to interrupt attributes of other platforms. Migrated from https://reviews.llvm.org/D159317 Added: Modified: clang/include/clang/Basic/Attr.td clang/include/clang/Basic/AttrDocs.td Removed: ################################################################################ diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td index c95db7e8049d47a..21a3b5226623cf2 100644 --- a/clang/include/clang/Basic/Attr.td +++ b/clang/include/clang/Basic/Attr.td @@ -3125,7 +3125,7 @@ def AnyX86Interrupt : InheritableAttr, TargetSpecificAttr<TargetAnyX86> { let Subjects = SubjectList<[HasFunctionProto]>; let ParseKind = "Interrupt"; let HasCustomParsing = 1; - let Documentation = [Undocumented]; + let Documentation = [AnyX86InterruptDocs]; } def AnyX86NoCallerSavedRegisters : InheritableAttr, diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td index f11ea89d14bad0d..c3fe7cea29afbf1 100644 --- a/clang/include/clang/Basic/AttrDocs.td +++ b/clang/include/clang/Basic/AttrDocs.td @@ -4801,6 +4801,54 @@ Marking virtual functions as ``disable_tail_calls`` is legal. }]; } +def AnyX86InterruptDocs : Documentation { + let Category = DocCatFunction; + let Heading = "interrupt (X86)"; + let Content = [{ +Clang supports the GNU style ``__attribute__((interrupt))`` attribute on X86 +targets. This attribute may be attached to a function definition and instructs +the backend to generate appropriate function entry/exit code so that it can be +used directly as an interrupt service routine. + +Interrupt handlers have access to the stack frame pushed onto the stack by the processor, +and return using the ``IRET`` instruction. All registers in an interrupt handler are callee-saved. +Exception handlers also have access to the error code pushed onto the stack by the processor, +when applicable. + +An interrupt handler must take the following arguments: + + .. code-block:: c + + __attribute__ ((interrupt)) + void f (struct stack_frame *frame) { + ... + } + + Where ``struct stack_frame`` is a suitable struct matching the stack frame pushed by the + processor. + +An exception handler must take the following arguments: + + .. code-block:: c + + __attribute__ ((interrupt)) + void g (struct stack_frame *frame, unsigned long code) { + ... + } + + On 32-bit targets, the ``code`` argument should be of type ``unsigned int``. + +Exception handlers should only be used when an error code is pushed by the processor. +Using the incorrect handler type will crash the system. + +Interrupt and exception handlers cannot be called by other functions and must have return type ``void``. + +Interrupt and exception handlers should only call functions with the 'no_caller_saved_registers' +attribute, or should be compiled with the '-mgeneral-regs-only' flag to avoid saving unused +non-GPR registers. + }]; +} + def AnyX86NoCallerSavedRegistersDocs : Documentation { let Category = DocCatFunction; let Content = [{ _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits