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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187352 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nico Rieck 2013-07-29 12:30:12 +00:00
parent c16babf693
commit c63dce3c59
2 changed files with 76 additions and 11 deletions

View File

@ -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());
const unsigned Max6DecimalSize = 999999;
const unsigned Max7DecimalSize = 9999999;
uint64_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));
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());

View File

@ -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