From 2c9c89b21d272eafb19f993c9e7c055d87a4e7fb Mon Sep 17 00:00:00 2001 From: Nico Rieck Date: Mon, 29 Jul 2013 12:30:12 +0000 Subject: [PATCH] MC: Support larger COFF string tables Single-slash encoded entries do not require a terminating null. This bumps the maximum table size from ~1MB to ~9.5MB. llvm-svn: 187352 --- llvm/lib/MC/WinCOFFObjectWriter.cpp | 27 ++++++++------ llvm/test/MC/COFF/section-name-encoding.s | 62 +++++++++++++++++++++++++++++++ 2 files changed, 77 insertions(+), 12 deletions(-) create mode 100644 llvm/test/MC/COFF/section-name-encoding.s diff --git a/llvm/lib/MC/WinCOFFObjectWriter.cpp b/llvm/lib/MC/WinCOFFObjectWriter.cpp index 28e611f..4e26934 100644 --- a/llvm/lib/MC/WinCOFFObjectWriter.cpp +++ b/llvm/lib/MC/WinCOFFObjectWriter.cpp @@ -475,18 +475,21 @@ void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData, /// name into the string table if needed void WinCOFFObjectWriter::MakeSectionReal(COFFSection &S, size_t Number) { if (S.Name.size() > COFF::NameSize) { - size_t StringTableEntry = Strings.insert(S.Name.c_str()); - - // FIXME: Why is this number 999999? This number is never mentioned in the - // spec. I'm assuming this is due to the printed value needing to fit into - // the S.Header.Name field. In which case why not 9999999 (7 9's instead of - // 6)? The spec does not state if this entry should be null terminated in - // this case, and thus this seems to be the best way to do it. I think I - // just solved my own FIXME... - if (StringTableEntry > 999999) - report_fatal_error("COFF string table is greater than 999999 bytes."); - - std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry)); + const unsigned Max6DecimalSize = 999999; + const unsigned Max7DecimalSize = 9999999; + uint64_t StringTableEntry = Strings.insert(S.Name.c_str()); + + if (StringTableEntry <= Max6DecimalSize) { + std::sprintf(S.Header.Name, "/%d", unsigned(StringTableEntry)); + } else if (StringTableEntry <= Max7DecimalSize) { + // With seven digits, we have to skip the terminating null. Because + // sprintf always appends it, we use a larger temporary buffer. + char buffer[9] = { }; + std::sprintf(buffer, "/%d", unsigned(StringTableEntry)); + std::memcpy(S.Header.Name, buffer, 8); + } else { + report_fatal_error("COFF string table is greater than 9,999,999 bytes."); + } } else std::memcpy(S.Header.Name, S.Name.c_str(), S.Name.size()); diff --git a/llvm/test/MC/COFF/section-name-encoding.s b/llvm/test/MC/COFF/section-name-encoding.s new file mode 100644 index 0000000..0f531f3 --- /dev/null +++ b/llvm/test/MC/COFF/section-name-encoding.s @@ -0,0 +1,62 @@ +// Check that COFF section names are properly encoded. +// +// Encodings for different lengths: +// [0, 8]: raw name +// (8, 999999]: base 10 string table index (/9999999) +// +// RUN: llvm-mc -triple x86_64-pc-win32 -filetype=obj %s | llvm-readobj -s | FileCheck %s + +// Raw encoding + +// CHECK: Section { +// CHECK: Number: 1 +// CHECK: Name: s (73 00 00 00 00 00 00 00) +// CHECK: } +// CHECK: Section { +// CHECK: Number: 2 +// CHECK: Name: s1234567 (73 31 32 33 34 35 36 37) +// CHECK: } +.section s; .long 1 +.section s1234567; .long 1 + + +// Base 10 encoding + +// /4 +// CHECK: Section { +// CHECK: Number: 3 +// CHECK: Name: s12345678 (2F 34 00 00 00 00 00 00) +// CHECK: } +.section s12345678; .long 1 + + +// Generate padding sections to increase the string table size to at least +// 1,000,000 bytes. +.macro pad_sections2 pad + // 10x \pad + .section p0\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad; .long 1 + .section p1\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad; .long 1 + .section p2\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad; .long 1 + .section p3\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad; .long 1 + .section p4\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad; .long 1 +.endm + +.macro pad_sections pad + // 20x \pad + pad_sections2 \pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad\pad +.endm + +// 1000x 'a' +pad_sections aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + + +// /1000029 == 4 + 10 + (5 * (2 + (20 * 10 * 1000) + 1)) +// v | | v ~~~~~~~~~~~~~~ v +// table size v v "p0" pad NUL seperator +// "s12345678\0" # of pad sections +// +// CHECK: Section { +// CHECK: Number: 9 +// CHECK: Name: seven_digit (2F 31 30 30 30 30 32 39) +// CHECK: } +.section seven_digit; .long 1 -- 2.7.4