Commit 797b68c0 authored by Martin Storsjö's avatar Martin Storsjö
Browse files

Revert "[MC][AsmParser] Diagnose improperly nested .cfi frames" 

This reverts commit 4323da92.

This broke building libffi for ARM on Windows (and probably Darwin),
where one extern function intentionally falls through to another
one, while sharing one CFI region.

As long as one isn't using .subsections_via_symbols on MachO,
this probably shouldn't be a hard error.

Secondly, the tested pattern only produces an error on MachO and
COFF targets, but not for ELF, making the error case even more
inconsistent.

Reverting this commit for now, to figure out the best way forward.
parent 9ae04a77

lld/test/COFF/gc-dwarf-eh.s

+2 −2
Original line number Diff line number Diff line
@@ -13,9 +13,9 @@ 
	.def	_main; .scl	2; .type	32; .endef

	.section	.text,"xr",one_only,_main

	.globl	_main

_main:

	.cfi_startproc

	.cfi_personality 0, ___gxx_personality_v0

_main:

	xorl	%eax, %eax

	ret

	.cfi_endproc
@@ -29,8 +29,8 @@ ___gxx_personality_v0: 
	.def	_unused; .scl	2; .type	32; .endef

	.section	.text,"xr",one_only,_unused

	.globl	_unused

_unused:

	.cfi_startproc

	.cfi_personality 0, ___gxx_personality_v0

_unused:

	ret

	.cfi_endproc

llvm/lib/MC/MCParser/AsmParser.cpp

+0 −11
Original line number Diff line number Diff line
@@ -125,7 +125,6 @@ private: 
  void *SavedDiagContext;

  std::unique_ptr<MCAsmParserExtension> PlatformParser;

  SMLoc StartTokLoc;

  std::optional<SMLoc> CFIStartProcLoc;



  /// This is the current buffer index we're lexing from as managed by the

  /// SourceMgr object.
@@ -1950,11 +1949,6 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info, 
      Lex();

    }



    if (CFIStartProcLoc && Sym->isExternal())

      return Error(StartTokLoc, "non-private labels cannot appear between "

                                ".cfi_startproc / .cfi_endproc pairs") &&

             Error(*CFIStartProcLoc, "previous .cfi_startproc was here");



    if (discardLTOSymbol(IDVal))

      return false;
@@ -4199,8 +4193,6 @@ bool AsmParser::parseDirectiveCFISections() { 
/// parseDirectiveCFIStartProc

/// ::= .cfi_startproc [simple]

bool AsmParser::parseDirectiveCFIStartProc() {

  CFIStartProcLoc = StartTokLoc;



  StringRef Simple;

  if (!parseOptionalToken(AsmToken::EndOfStatement)) {

    if (check(parseIdentifier(Simple) || Simple != "simple",
@@ -4221,11 +4213,8 @@ bool AsmParser::parseDirectiveCFIStartProc() { 
/// parseDirectiveCFIEndProc

/// ::= .cfi_endproc

bool AsmParser::parseDirectiveCFIEndProc() {

  CFIStartProcLoc = std::nullopt;



  if (parseEOL())

    return true;



  getStreamer().emitCFIEndProc();

  return false;

}

llvm/test/MC/AArch64/cfi-bad-nesting.s

deleted100644 → 0
+0 −23
Original line number Diff line number Diff line 
; RUN: not llvm-mc -triple arm64-apple-darwin %s -filetype=obj -o /dev/null 2>&1 | FileCheck %s



; REQUIRES: aarch64-registered-target



	.section	__TEXT,locomotive,regular,pure_instructions



	.globl	_locomotive

	.p2align	2

_locomotive:

	.cfi_startproc

	ret



	; It is invalid to have a non-private label between .cfi_startproc / .cfi_endproc

	.section	__TEXT,__text,regular,pure_instructions

	.globl	_caboose

	.p2align	2

_caboose:

; CHECK: [[#@LINE-1]]:1: error: non-private labels cannot appear between .cfi_startproc / .cfi_endproc pairs

; CHECK: [[#@LINE-9]]:2: error: previous .cfi_startproc was here

	ret

	.cfi_endproc



.subsections_via_symbols
 
 No newline at end of file