diff options
Diffstat (limited to 'lib/CodeGen/AsmPrinter/DwarfException.cpp')
| -rw-r--r-- | lib/CodeGen/AsmPrinter/DwarfException.cpp | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/lib/CodeGen/AsmPrinter/DwarfException.cpp b/lib/CodeGen/AsmPrinter/DwarfException.cpp index 79200198c5..7efa6429e1 100644 --- a/lib/CodeGen/AsmPrinter/DwarfException.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfException.cpp @@ -745,10 +745,52 @@ void DwarfException::EmitExceptionTable() { TTypeBaseOffset; // TType base offset unsigned SizeAlign = (4 - TotalSize) & 3; - if (HaveTTData) + if (HaveTTData) { // Account for any extra padded that will be added to the call site table // length. - EmitULEB128(TTypeBaseOffset + SizeAlign, "@TType base offset"); + unsigned Offset = TTypeBaseOffset + SizeAlign; + unsigned OffsetSize = MCAsmInfo::getULEB128Size(Offset); + unsigned TTypeBaseOverflow = 0; + + // If adding the extra alignment to the TType base offset makes the new + // value of TTypeBaseOffset overflow (i.e., go from encoded as 1 byte to 2 + // bytes), then the padding needs to be smaller by that amount. + if (OffsetSize != TTypeBaseOffsetSize) { + assert((int)OffsetSize - (int)TTypeBaseOffsetSize); + TTypeBaseOverflow = OffsetSize - TTypeBaseOffsetSize; + assert(TTypeBaseOffsetSize >= SizeAlign); + SizeAlign -= TTypeBaseOverflow; + } + + if (!TTypeBaseOverflow || SizeAlign != 0) + EmitULEB128(Offset, "@TType base offset"); + else + // If adding the extra padding to this offset causes it to buffer to the + // size of the padding needed, then we should perform the padding here and + // not at the call site table below. E.g. if we have this: + // + // GCC_except_table1: + // Lexception1: + // .byte 0xff ## @LPStart Encoding = omit + // .byte 0x9b ## @TType Encoding = indirect pcrel sdata4 + // .byte 0x7f ## @TType base offset + // .byte 0x03 ## Call site Encoding = udata4 + // .byte 0x89 ## Call site table length + // + // with padding of 1. We want to emit the padding like this: + // + // GCC_except_table1: + // Lexception1: + // .byte 0xff ## @LPStart Encoding = omit + // .byte 0x9b ## @TType Encoding = indirect pcrel sdata4 + // .byte 0xff ## @TType base offset + // .space 1,0 ## Padding + // .byte 0x03 ## Call site Encoding = udata4 + // .byte 0x89 ## Call site table length + // + // and not with padding on the "Call site table length" entry. + EmitULEB128(TTypeBaseOffset, "@TType base offset", TTypeBaseOverflow); + } // SjLj Exception handling if (IsSJLJ) { |