Commit Graph

63 Commits

Author SHA1 Message Date
Brian Smith
9da82c1ccc Remove superfluous crypto/bio dependencies from tests.
Limiting uses of crypto/bio to code that really need to it by avoiding
the use of BIO just to write to stdout/stderr.

Change-Id: I34e0f773161aeec073691e439ac353fb7b1785f3
Reviewed-on: https://boringssl-review.googlesource.com/3930
Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 20:24:18 +00:00
Brian Smith
83a82981dc Rename BIO_print_errors_fp back to ERR_print_errors_fp & refactor it.
A previous change in BoringSSL renamed ERR_print_errors_fp to
BIO_print_errors_fp as part of refactoring the code to improve the
layering of modules within BoringSSL. Rename it back for better
compatibility with code that was using the function under the original
name. Move its definition back to crypto/err using an implementation
that avoids depending on crypto/bio.

Change-Id: Iee7703bb1eb4a3d640aff6485712bea71d7c1052
Reviewed-on: https://boringssl-review.googlesource.com/4310
Reviewed-by: Adam Langley <agl@google.com>
2015-04-13 20:23:29 +00:00
David Benjamin
89baa72ed8 Define __STDC_FORMAT_MACROS before inttypes.h.
It seems Android's inttypes.h refuses to define those macros on C++ unless
__STDC_FORMAT_MACROS is set. This unbreaks the roll on Android.

Change-Id: Iad6c971b4789f0302534d9e5022534c6124e0ff0
Reviewed-on: https://boringssl-review.googlesource.com/4202
Reviewed-by: Adam Langley <agl@google.com>
2015-04-02 18:39:18 +00:00
David Benjamin
a5974bfae7 Convert bn_test to C++.
Along the way, fix a host of missing failure checks. This will save some
headache when it comes time to run these under the malloc failure tests.

Change-Id: I3fd589bd094178723398e793d6bc578884e99b67
Reviewed-on: https://boringssl-review.googlesource.com/4126
Reviewed-by: Adam Langley <agl@google.com>
2015-04-01 19:53:51 +00:00
David Benjamin
42574efaff Avoid undefined behavior in probable_prime.
(Imported from upstream's e4676e900f165f5272991443225813002300b09b.)

Change-Id: I678e158c223daf2f7f9114f4e743d531fe2e2a93
Reviewed-on: https://boringssl-review.googlesource.com/4044
Reviewed-by: Adam Langley <agl@google.com>
2015-03-19 11:36:49 +00:00
David Benjamin
c02f148fa8 Fix error handling in bn_exp
In the event of an error |rr| could be NULL. Therefore don't assume you can
use |rr| in the error handling code.

(Imported from upstream's 8c5a7b33c6269c3bd6bc0df6b4c22e4fba03b485.)

Change-Id: I0b392991ce8170dc418e93003af256d535d1e2e8
Reviewed-on: https://boringssl-review.googlesource.com/4005
Reviewed-by: Adam Langley <agl@google.com>
2015-03-19 11:10:27 +00:00
David Benjamin
1a5c50f3a8 Error codes are uint32_t, not unsigned long.
Fix a few remnants of them being unsigned long. Also rename extremely unhelpful
variable names in SSL_get_error. i is now ret_code to match the header.

Change-Id: Ic31d6626bfe09c9e21c03691dfc716c5573833ea
Reviewed-on: https://boringssl-review.googlesource.com/3881
Reviewed-by: Adam Langley <agl@google.com>
2015-03-13 19:41:42 +00:00
David Benjamin
09bdb2a2c3 Remove explicit .hiddens from x86_64 perlasm files.
This reverts the non-ARM portions of 97999919bb.
x86_64 perlasm already makes .globl imply .hidden. (Confusingly, ARM does not.)
Since we don't need it, revert those to minimize divergence with upstream.

Change-Id: I2d205cfb1183e65d4f18a62bde187d206b1a96de
Reviewed-on: https://boringssl-review.googlesource.com/3610
Reviewed-by: Adam Langley <agl@google.com>
2015-02-25 21:26:16 +00:00
Adam Langley
97999919bb Hide all asm symbols.
We are leaking asm symbols in Android builds because the asm code isn't
affected by -fvisibility=hidden. This change hides all asm symbols.

This assumes that no asm symbols are public API and that should be true.
Some points to note:

In crypto/rc4/asm/rc4-md5-x86_64.pl there are |RC4_set_key| and
|RC4_options| functions which aren't getting marked as hidden. That's
because those functions aren't actually ever generated. (I'm just trying
to minimise drift with upstream here.)

In crypto/rc4/asm/rc4-x86_64.pl there's |RC4_options| which is "public"
API, except that we've never had it in the header files. So I've just
deleted it. Since we have an internal caller, we'll probably have to put
it back in the future, but it can just be done in rc4.c to save
problems.

BUG=448386

Change-Id: I3846617a0e3d73ec9e5ec3638a53364adbbc6260
Reviewed-on: https://boringssl-review.googlesource.com/3520
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2015-02-20 21:24:01 +00:00
Adam Langley
16e38b2b8f Mark OPENSSL_armcap_P as hidden in ARM asm.
This is an import from ARM. Without this, one of the Android builds of
BoringSSL was failing with:
  (sha512-armv4.o): requires unsupported dynamic reloc R_ARM_REL32; recompile with -fPIC

This is (I believe) a very misleading error message. The R_ARM_REL32
relocation type is the correct type for position independent code. But
unless the target symbol is hidden then the linker doesn't know that
it's not going to be overridden by a different ELF module.

Chromium probably gets away with this because of different default
compiler flags than Android.

Change-Id: I967eabc4d6b33d1e6635caaf6e7a306e4e77c101
Reviewed-on: https://boringssl-review.googlesource.com/3471
Reviewed-by: Adam Langley <agl@google.com>
2015-02-19 19:58:17 +00:00
David Benjamin
9d0847ae6d Add some missing error failure checks.
Found while diagnosing some crashes and hangs in the malloc tests. This (and
the follow-up) get us further but does not quite let the malloc tests pass
quietly, even without valgrind. DTLS silently ignores some malloc failures
(confusion with silently dropping bad packets) which then translate to hangs.

Change-Id: Ief06a671e0973d09d2883432b89a86259e346653
Reviewed-on: https://boringssl-review.googlesource.com/3482
Reviewed-by: Adam Langley <agl@google.com>
2015-02-17 20:55:56 +00:00
David Benjamin
3673be7cb6 Fix standalone build on Win64.
Win64 fires significantly more warnings than Win32. Also some recent
changes made it grumpy.

(We might want to reconsider enabling all of MSVC's warnings. Given the sorts
of warnings some of these are, I'm not sure MSVC's version of -Wall -Werror is
actually tenable. Plus, diverging from the Chromium build, especially before
the bots are ready, is going to break pretty readily.)

Change-Id: If3b8feccf910ceab4a233b0731e7624d7da46f87
Reviewed-on: https://boringssl-review.googlesource.com/3420
Reviewed-by: Adam Langley <agl@google.com>
2015-02-11 23:13:52 +00:00
David Benjamin
c9a202fee3 Add in missing curly braces part 1.
Everything before crypto/ec.

Change-Id: Icbfab8e4ffe5cc56bf465eb57d3fdad3959a085c
Reviewed-on: https://boringssl-review.googlesource.com/3401
Reviewed-by: Adam Langley <agl@google.com>
2015-02-11 19:31:01 +00:00
Adam Langley
29b186736c Precompute sorted array for error strings.
Previously, error strings were kept in arrays for each subdirectory and
err.c would iterate over them all and insert them at init time to a hash
table.

This means that, even if you have a shared library and lots of processes
using that, each process has ~30KB of private memory from building that
hash table.

This this change, all the error strings are built into a sorted list and
are thus static data. This means that processes can share the error
information and it actually saves binary space because of all the
pointer overhead in the old scheme. Also it saves the time taken
building the hash table at startup.

This removes support for externally-supplied error string data.

Change-Id: Ifca04f335c673a048e1a3e76ff2b69c7264635be
2015-02-09 17:35:31 -08:00
Adam Langley
2b2d66d409 Remove string.h from base.h.
Including string.h in base.h causes any file that includes a BoringSSL
header to include string.h. Generally this wouldn't be a problem,
although string.h might slow down the compile if it wasn't otherwise
needed. However, it also causes problems for ipsec-tools in Android
because OpenSSL didn't have this behaviour.

This change removes string.h from base.h and, instead, adds it to each
.c file that requires it.

Change-Id: I5968e50b0e230fd3adf9b72dd2836e6f52d6fb37
Reviewed-on: https://boringssl-review.googlesource.com/3200
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2015-02-02 19:14:15 +00:00
Brian Smith
efed2210e8 Enable more warnings & treat warnings as errors on Windows.
Change-Id: I2bf0144aaa8b670ff00b8e8dfe36bd4d237b9a8a
Reviewed-on: https://boringssl-review.googlesource.com/3140
Reviewed-by: Adam Langley <agl@google.com>
2015-01-31 00:18:55 +00:00
Adam Langley
9115755006 Convert latin-1 files to UTF-8.
A handful of latin-1 codepoints existed a trio of files. This change
switches the encoding to UTF-8.

Change-Id: I00309e4d1ee3101e0cc02abc53196eafa17a4fa5
2015-01-29 17:26:36 -08:00
Adam Langley
4a0f0c4910 Change CMakeLists.txt to two-space indent.
find -name CMakeLists.txt -type f | xargs sed -e 's/\t/  /g' -i

Change-Id: I01636b1849c00ba918f48828252492d99b0403ac
2015-01-28 16:37:10 -08:00
David Benjamin
347f025d75 Remove unused modexp512-x86_64.pl.
See upstream's c436e05bdc7f49985a750df64122c960240b3ae1.

Change-Id: I7cbe5315a769450e4630dd4e8f465cdfd45c2e08
Reviewed-on: https://boringssl-review.googlesource.com/3025
Reviewed-by: Adam Langley <agl@google.com>
2015-01-26 18:45:45 +00:00
David Benjamin
8604eda634 Add Broadwell performance results.
(Imported from upstream's b3d7294976c58e0e05d0ee44a0e7c9c3b8515e05.)

May as well avoid diverging.

Change-Id: I3edec4fe15b492dd3bfb3146a8944acc6575f861
Reviewed-on: https://boringssl-review.googlesource.com/3020
Reviewed-by: Adam Langley <agl@google.com>
2015-01-26 18:35:35 +00:00
Adam Langley
3e6526575a aarch64 support.
This is an initial cut at aarch64 support. I have only qemu to test it
however—hopefully hardware will be coming soon.

This also affects 32-bit ARM in that aarch64 chips can run 32-bit code
and we would like to be able to take advantage of the crypto operations
even in 32-bit mode. AES and GHASH should Just Work in this case: the
-armx.pl files can be built for either 32- or 64-bit mode based on the
flavour argument given to the Perl script.

SHA-1 and SHA-256 don't work like this however because they've never
support for multiple implementations, thus BoringSSL built for 32-bit
won't use the SHA instructions on an aarch64 chip.

No dedicated ChaCha20 or Poly1305 support yet.

Change-Id: Ib275bc4894a365c8ec7c42f4e91af6dba3bd686c
Reviewed-on: https://boringssl-review.googlesource.com/2801
Reviewed-by: Adam Langley <agl@google.com>
2015-01-14 23:38:11 +00:00
Adam Langley
a83cc803b1 Fix for CVE-2014-3570.
(With minor bn/generic.c revamp.)

(Imported from upstream's 56df92efb6893abe323307939425957ce878c8f0)

Change-Id: I9d85cfde4dfb29e64ff7417f781d0c9f1685e905
Reviewed-on: https://boringssl-review.googlesource.com/2780
Reviewed-by: Adam Langley <agl@google.com>
2015-01-09 02:49:10 +00:00
David Benjamin
a6d81018f8 Consistently use RAND_bytes and check for failure.
RAND_pseudo_bytes just calls RAND_bytes now and only returns 0 or 1. Switch all
callers within the library call the new one and use the simpler failure check.
This fixes a few error checks that no longer work (< 0) and some missing ones.

Change-Id: Id51c79deec80075949f73fa1fbd7b76aac5570c6
Reviewed-on: https://boringssl-review.googlesource.com/2621
Reviewed-by: Adam Langley <agl@google.com>
2014-12-16 19:15:59 +00:00
David Benjamin
61f1085ee9 Switch crypto/bn back to _umul128 on Windows clang.
Upstream (impressively quickly) fixed the missing intrinsic. Switch Windows
clang back to building the same code as MSVC. Also include the intrin.h header
rather than forward-declare the intrinsic. clang only works if the header is
explicitly included. Chromium forcibly includes it to work around these kinds
of issues, but we shouldn't rely on it.

BUG=crbug.com/438382

Change-Id: I0ff6d48e1a3aa455cff99f8dc4c407e88b84d446
Reviewed-on: https://boringssl-review.googlesource.com/2461
Reviewed-by: Adam Langley <agl@google.com>
2014-12-04 00:23:15 +00:00
David Benjamin
af9d9419a6 Don't use _umul128 for Windows clang.
Windows clang lacks _umul128, but it has inline assembly so just use
that.

Change-Id: I6ff5d2465edc703a4d47ef0efbcea43d6fcc79fa
Reviewed-on: https://boringssl-review.googlesource.com/2454
Reviewed-by: Adam Langley <agl@google.com>
2014-12-02 20:28:25 +00:00
David Benjamin
9ecafa5c78 Shush some dead assignments.
Appease clang scan-build a bit. I'm not sure it's actually worth silencing all
of them because some of them look like preserving invariants between local
variables, but some are clearly pointless or can be restructured slightly.

Change-Id: I0bc81e2589bb402ff3ef0182d7a8921e31b85052
Reviewed-on: https://boringssl-review.googlesource.com/2205
Reviewed-by: Adam Langley <agl@google.com>
2014-11-06 01:34:33 +00:00
Adam Langley
25cb99c149 crypto/bn/asm/rsaz-*.pl: allow spaces in Perl path name.
(Imported from upstream's ef908777218bd4a362dbe9cebb8e18fa8ab384cf.)

Change-Id: Id9b288d230cc9d8ab308690a18e687e2132e3293
Reviewed-on: https://boringssl-review.googlesource.com/2168
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2014-11-05 21:26:15 +00:00
David Benjamin
029a779204 Remove BN_LONG macro.
It's never used, upstream or downstream. The 64-bit value is wrong anyway for
LLP64 platforms.

Change-Id: I56afc51f4c17ed3f1c30959b574034f181b5b0c7
Reviewed-on: https://boringssl-review.googlesource.com/2123
Reviewed-by: Adam Langley <agl@google.com>
2014-11-04 00:27:40 +00:00
David Benjamin
8b1d900c52 Fix unused variables in bn/generic.c
bl and bh are never used by macros if either BN_UMULT_LOHI or
BN_UMULT_HIGH are defined.

Change-Id: I7fdd45014a6b78cc586b5223396e09bc213608a5
Reviewed-on: https://boringssl-review.googlesource.com/2105
Reviewed-by: Adam Langley <agl@google.com>
2014-11-03 20:52:10 +00:00
David Benjamin
f44aa68a26 Fix standalone Win64 build.
generic.c still needs to include generic implementations in Win64.
Those are currently done with inline assembly and won't work on
MSVC.

Change-Id: Ifeb5470872d8c97b2ccffeae6f3ccb5661051de3
Reviewed-on: https://boringssl-review.googlesource.com/2102
Reviewed-by: Adam Langley <agl@google.com>
2014-10-31 22:00:45 +00:00
David Benjamin
3e700bb3e8 Get MASM output working on Win32.
We were building the NASM flavor with MASM which is why it didn't work. Get the
MASM output working: cpuid and cmove are not available in MASM unless the file
declares .686. Also work around MASM rejecting a very long line in SHA-256.

The follow-up change will get the NASM flavor working. We should probably use
that one as it's documented as supported upstream. But let's make this one
functional too.

Change-Id: Ica69cc042a7250c7bc9ba9325caab597cd4ce616
Reviewed-on: https://boringssl-review.googlesource.com/2091
Reviewed-by: Adam Langley <agl@google.com>
2014-10-29 23:13:20 +00:00
David Benjamin
fb3ff2c66c Don't compare signed vs. unsigned.
This resolves a pile of MSVC warnings in Chromium.

Change-Id: Ib9a29cb88d8ed8ec4118d153260f775be059a803
Reviewed-on: https://boringssl-review.googlesource.com/1865
Reviewed-by: Adam Langley <agl@google.com>
2014-10-01 02:17:38 +00:00
David Benjamin
a70c75cfc0 Add a CRYPTO_library_init and static-initializer-less build option.
Chromium does not like static initializers, and the CPU logic uses one to
initialize CPU bits. However, the crypto library lacks an explicit
initialization function, which could complicate (no compile-time errors)
porting existing code which uses crypto/, but not ssl/.

Add an explicit CRYPTO_library_init function, but make it a no-op by default.
It only does anything (and is required) if building with
BORINGSSL_NO_STATIC_INITIALIZER.

Change-Id: I6933bdc3447fb382b1f87c788e5b8142d6f3fe39
Reviewed-on: https://boringssl-review.googlesource.com/1770
Reviewed-by: Adam Langley <agl@google.com>
2014-09-12 00:10:53 +00:00
David Benjamin
c44d2f4cb8 Convert all zero-argument functions to '(void)'
Otherwise, in C, it becomes a K&R function declaration which doesn't actually
type-check the number of arguments.

Change-Id: I0731a9fefca46fb1c266bfb1c33d464cf451a22e
Reviewed-on: https://boringssl-review.googlesource.com/1582
Reviewed-by: Adam Langley <agl@google.com>
2014-08-21 01:06:07 +00:00
Adam Langley
b8b5478248 Expose two, rather internal, BIGNUM functions.
Android uses these for some conversions from Java formats. The code is
sufficiently bespoke that putting the conversion functions into
BoringSSL doesn't make a lot of sense, but the alternative is to expose
these ones.

Change-Id: If1362bc4a5c44cba4023c909e2ba6488ae019ddb
2014-08-14 09:42:45 -07:00
David Benjamin
bf681a40d6 Fix out-of-bounds read in BN_mod_exp_mont_consttime.
bn_get_bits5 always reads two bytes, even when it doesn't need to. For some
sizes of |p|, this can result in reading just past the edge of the array.
Unroll the first iteration of the loop and avoid reading out of bounds.

Replace bn_get_bits5 altogether in C as it's not doing anything interesting.

Change-Id: Ibcc8cea7d9c644a2639445396455da47fe869a5c
Reviewed-on: https://boringssl-review.googlesource.com/1393
Reviewed-by: Adam Langley <agl@google.com>
2014-08-06 00:11:47 +00:00
Adam Langley
eb7d2ed1fe Add visibility rules.
This change marks public symbols as dynamically exported. This means
that it becomes viable to build a shared library of libcrypto and libssl
with -fvisibility=hidden.

On Windows, one not only needs to mark functions for export in a
component, but also for import when using them from a different
component. Because of this we have to build with
|BORINGSSL_IMPLEMENTATION| defined when building the code. Other
components, when including our headers, won't have that defined and then
the |OPENSSL_EXPORT| tag becomes an import tag instead. See the #defines
in base.h

In the asm code, symbols are now hidden by default and those that need
to be exported are wrapped by a C function.

In order to support Chromium, a couple of libssl functions were moved to
ssl.h from ssl_locl.h: ssl_get_new_session and ssl_update_cache.

Change-Id: Ib4b76e2f1983ee066e7806c24721e8626d08a261
Reviewed-on: https://boringssl-review.googlesource.com/1350
Reviewed-by: Adam Langley <agl@google.com>
2014-07-31 22:03:11 +00:00
David Benjamin
7bbeead507 A bunch of dead assignments.
Caught by clang scan-build.

Change-Id: I4f10c879dc137d4a14a7a395764d28e5caa033ff
Reviewed-on: https://boringssl-review.googlesource.com/1342
Reviewed-by: Adam Langley <agl@google.com>
2014-07-30 00:44:03 +00:00
Adam Langley
4b5979b3fa x86_64 assembly pack: improve masm support.
(Imported from upstream's 371feee876dd8b58531cb6e50fe79262db8e4ed7)

Change-Id: Id3b5ece6b5e5f0565060d5e598ea265d64dac9df
2014-07-28 17:05:13 -07:00
Adam Langley
43dca4d8bb fix x86_64-specific crash with one-word modulus.
PR: #3397

(Imported from upstream's 47b9e06cfd3a4fa89a690309e5839ed57e93f0f8)

Change-Id: I92d46a3132233c179f4b708d506bfb7212c26a33
2014-07-28 17:05:13 -07:00
Adam Langley
2811da2eca x86_64 assembly pack: allow clang to compile AVX code.
(Imported from upstream's 912f08dd5ed4f68fb275f3b2db828349fcffba14,
52f856526c46ee80ef4c8c37844f084423a3eff7 and
377551b9c4e12aa7846f4d80cf3604f2e396c964)

Change-Id: Ic2bf93371f6d246818729810e7a45b3f0021845a
2014-07-28 17:05:13 -07:00
Adam Langley
b351d83875 bn/asm/rsaz-avx2.pl: fix occasional failures.
(Imported from upstream's 1067663d852435b1adff32ec01e9b8e54d2b5896)

Change-Id: I39e2a24176306f4170449145d3dee2c2edbf6dfe
2014-07-28 17:05:12 -07:00
Adam Langley
ac71c09529 Make sure BN_sqr can never return a negative value.
PR#3410

(Imported from upstream's b7a4f98b152e5b9a56da1501e73053d83a9799b6)

Change-Id: I382c12f205d9adbd418574f7938a1d55a07128e4
2014-07-28 17:05:12 -07:00
Adam Langley
25ba90e34a move check for AD*X to rsaz-avx2.pl.
This ensures high performance is situations when assembler supports
AVX2, but not AD*X.

(Imported from upstream's 82a9dafe32e1e39b5adff18f9061e43d8df3d3c5)

Change-Id: Ie67f49a1c5467807139b6a8a0d4e62162d8a974f
2014-07-28 17:05:12 -07:00
Adam Langley
4c921e1bbc Move public headers to include/openssl/
Previously, public headers lived next to the respective code and there
were symlinks from include/openssl to them.

This doesn't work on Windows.

This change moves the headers to live in include/openssl. In cases where
some symlinks pointed to the same header, I've added a file that just
includes the intended target. These cases are all for backwards-compat.

Change-Id: I6e285b74caf621c644b5168a4877db226b07fd92
Reviewed-on: https://boringssl-review.googlesource.com/1180
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2014-07-14 22:42:18 +00:00
Adam Langley
0113a4fb60 Support building with PNaCl.
PNaCl needs OPENSSL_NO_ASM to work and a couple of cases were missing
because it hasn't previously been tested.

Additionally, it defined _BSD_SOURCE and others on the command line,
causing duplicate definition errors when defined in source code.

It's missing readdir_r.

It uses newlib, which appears to use u_short in socket.h without ever
defining it.

Change-Id: Ieccfc7365723d0521f6327eebe9f44a2afc57406
Reviewed-on: https://boringssl-review.googlesource.com/1140
Reviewed-by: Adam Langley <agl@google.com>
2014-07-11 19:04:04 +00:00
Adam Langley
23b460df02 Add #ifdefs so RSAZ is only built on x86-64.
Change-Id: I5ec6b59e75120029348ce71c76e49a2d6e010913
2014-07-08 15:27:43 -07:00
Adam Langley
7ac79ebe55 The asm files bn/asm/x86* weren't actually used.
(This appears to be the case with upstream too, it's not that BoringSSL
is missing optimisations from what I can see.)

Change-Id: I0e54762ef0d09e60994ec82c5cca1ff0b3b23ea4
Reviewed-on: https://boringssl-review.googlesource.com/1080
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2014-07-02 00:29:12 +00:00
Adam Langley
5d17dd64cc Very minor BN fixes.
Fixes one comment that mentioned the wrong function name. Also causes
two BN random functions to fail when the output is NULL. Previously they
would silently do nothing.

Change-Id: I89796ab855ea32787765c301a478352287e61190
2014-06-30 14:22:32 -07:00
Adam Langley
30eda1d2b8 Include some build fixes for OS X.
Apart from the obvious little issues, this also works around a
(seeming) libtool/linker:

a.c defines a symbol:

int kFoo;

b.c uses it:

extern int kFoo;

int f() {
  return kFoo;
}

compile them:

$ gcc -c a.c
$ gcc -c b.c

and create a dummy main in order to run it, main.c:

int f();

int main() {
  return f();
}

this works as expected:

$ gcc main.c a.o b.o

but, if we make an archive:

$ ar q lib.a a.o b.o

and use that:

$ gcc main.c lib.a
Undefined symbols for architecture x86_64
  "_kFoo", referenced from:
    _f in lib.a(b.o)

(It doesn't matter what order the .o files are put into the .a)

Linux and Windows don't seem to have this problem.

nm on a.o shows that the symbol is of type "C", which is a "common symbol"[1].
Basically the linker will merge multiple common symbol definitions together.

If ones makes a.c read:

int kFoo = 0;

Then one gets a type "D" symbol - a "data section symbol" and everything works
just fine.

This might actually be a libtool bug instead of an ld bug: Looking at `xxd
lib.a | less`, the __.SYMDEF SORTED index at the beginning of the archive
doesn't contain an entry for kFoo unless initialised.

Change-Id: I4cdad9ba46e9919221c3cbd79637508959359427
2014-06-24 11:15:12 -07:00