The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/47f9431d5a69ae9e81faa6472d8b5a188eb63242

commit 47f9431d5a69ae9e81faa6472d8b5a188eb63242
Author: agrieve <agrieve@chromium.org>
Date: Wed May 03 18:41:04 2017

supersize: Tweak diff symbol matching for generated symbols

E.g. CSWTCH.61 and CSWTCH.62 will now match as long as they are in the
same object file.

BUG= 708865 , 717550 

Review-Url: https://codereview.chromium.org/2857153002
Cr-Commit-Position: refs/heads/master@{#469045}

[modify] https://crrev.com/47f9431d5a69ae9e81faa6472d8b5a188eb63242/tools/binary_size/libsupersize/diff.py
[modify] https://crrev.com/47f9431d5a69ae9e81faa6472d8b5a188eb63242/tools/binary_size/libsupersize/integration_test.py
[modify] https://crrev.com/47f9431d5a69ae9e81faa6472d8b5a188eb63242/tools/binary_size/libsupersize/models.py

More examples in  bug 718888 .

Some names found in the diff:
+ 10622)  4733437 (1900.8%) b@0x72ea7b0  168     /tmp/lto-llvm-2a2aff.o
               _ZN10extensionsL9g_factoryE.303474
+ 10623)  4733437 (1900.8%) b@0x72ea860  172     /tmp/lto-llvm-2a2aff.o
               _ZN10extensionsL9g_factoryE.303498
+ 10624)  4733437 (1900.8%) b@0x72ea978  4       /tmp/lto-llvm-2a2aff.o
               _ZZN12_GLOBAL__N_16GetKeyEvE9table_key.303731
+ 10625)  4733437 (1900.8%) b@0x72eda50  8       /tmp/lto-llvm-2a2aff.o
               GetCoeffs.316376
+ 10626)  4733437 (1900.8%) b@0x72ee734  4       /tmp/lto-llvm-2a2aff.o
               _ZN3gin12_GLOBAL__N_114g_wrapper_infoE.319492
+ 10627)  4733437 (1900.8%) b@0x72f33e0  8       /tmp/lto-llvm-2a2aff.o
               _ZN5blinkL14g_constructorsE.345637
+ 10628)  4733437 (1900.8%) b@0x72f4b80  16      /tmp/lto-llvm-2a2aff.o
               xsltTimestamp.startup
+ 10629)  4733437 (1900.8%) b@0x72f4b90  1001    /tmp/lto-llvm-2a2aff.o
               pretty_templ_match.dst
+ 10630)  4733437 (1900.8%) b@0x72f4f80  1       /tmp/lto-llvm-2a2aff.o
               xsltGenerateIdFunction.base_address
+ 10631)  4733437 (1900.8%) b@0x72f5440  778     /tmp/lto-llvm-2a2aff.o
               clip1.351274
- 10632)  4733365 (1900.7%) d@0x6d66ca0  -72     /tmp/lto-llvm-ec8278.o
               .L_ZTCN5blink22HTMLViewSourceDocumentE0_NS_12HTMLDocumentE.2
- 10633)  4733269 (1900.7%) d@0x6d66cf0  -96     /tmp/lto-llvm-ec8278.o
               .L_ZTCN5blink22HTMLViewSourceDocumentE0_NS_12HTMLDocumentE.3
- 10634)  4733197 (1900.7%) d@0x6d66d50  -72     /tmp/lto-llvm-ec8278.o
               .L_ZTCN5blink22HTMLViewSourceDocumentE0_NS_12HTMLDocumentE.4
- 10635)  4733187 (1900.7%) r@0x662a433  -10     /tmp/lto-llvm-ec8278.o
               _ZN12_GLOBAL__N_1L13kExpiresInKeyE.10011
- 10636)  4733155 (1900.7%) d@0x6d38db0  -32     /tmp/lto-llvm-ec8278.o
               .L_ZTVN12v8_inspector8protocol14DispatcherBase8CallbackE.0


From the above:
- .L_ sometime exists, sometimes does not.
- .### suffix often exists, and seems to break name demangling
- .dst and .base_address looks suspicious. Maybe added by lto.
- Object paths have a hash in them, but what is the hash of?

Minor correction: .L is the prefix, not .L_

Another thing to fix here: there isn't a good way to detect the --tool-prefix to use for Linux since we don't record it anywhere (in Android we currently use $OUT/build_vars.txt). 

We should probably start recording this, and change the name to buildargs.properties. 

Adding a couple of other things we need to fix (that may or may not be related):

1) Hitting "nm: *.o: File format not recognized"
  * Tried passing --tool-prefix third_party/binutils/Linux_x64/Release/bin/ and still hit the same error

2) Hitting "ELF file and .map file do not agree on section sizes."

Part of c8 was wrong because I didn't realize my map file was stale. Going to close this bug out as obsolete and track work at  issue 723798 .

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0f24feacbffe77af7d69f64e739c73d834fa19b4

commit 0f24feacbffe77af7d69f64e739c73d834fa19b4
Author: estevenson <estevenson@chromium.org>
Date: Thu May 18 16:17:42 2017

Use a GN arg for controlling linker map file generation.

Map files aren't generated on Linux by default now that linker map file
generation is hooked into !use_lld ( https://crbug.com/716209 ).

This CL adds a GN arg, enable_linker_map, that defaults to true for
Android and makes it easy to generate map files on Linux.

BUG= 717550 , 716209 

Review-Url: https://codereview.chromium.org/2888623003
Cr-Commit-Position: refs/heads/master@{#472834}

[modify] https://crrev.com/0f24feacbffe77af7d69f64e739c73d834fa19b4/build/toolchain/gcc_toolchain.gni
[modify] https://crrev.com/0f24feacbffe77af7d69f64e739c73d834fa19b4/build/toolchain/toolchain.gni
[modify] https://crrev.com/0f24feacbffe77af7d69f64e739c73d834fa19b4/tools/binary_size/diagnose_bloat.py