[llvm] r187352 - MC: Support larger COFF string tables
Nico Rieck
nico.rieck at gmail.com
Mon Jul 29 05:30:13 PDT 2013
Author: nrieck
Date: Mon Jul 29 07:30:12 2013
New Revision: 187352
URL: http://llvm.org/viewvc/llvm-project?rev=187352&view=rev
Log:
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.
Added:
llvm/trunk/test/MC/COFF/section-name-encoding.s
Modified:
llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
Modified: llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp?rev=187352&r1=187351&r2=187352&view=diff
==============================================================================
--- llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp Mon Jul 29 07:30:12 2013
@@ -475,18 +475,21 @@ void WinCOFFObjectWriter::DefineSymbol(M
/// 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());
Added: llvm/trunk/test/MC/COFF/section-name-encoding.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/COFF/section-name-encoding.s?rev=187352&view=auto
==============================================================================
--- llvm/trunk/test/MC/COFF/section-name-encoding.s (added)
+++ llvm/trunk/test/MC/COFF/section-name-encoding.s Mon Jul 29 07:30:12 2013
@@ -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 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!
aaaaaaaaa
aaaaaaaaaaaaaaaa
+
+
+// /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
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