llvm dev - Feb 2015 - [LLVMdev] Coverage mapping issue: Malformed profile data

Hi all!

It seems I came across on issue with coverage mapping
(http://www.llvm.org/docs/CoverageMappingFormat.html)

check on:
llvm revision: r228136
clang  Last Changed Rev: 228121
build: Debug+Asserts
OS: ubuntu 14.04


Here is simple snippets

test1.c: NOT OK
=================#include <stdio.h>

static int foo() { return 42; }
int main() {
 return 0;
}
=================cp src/test1.c src/test.c; rm -fr default.profraw test.profdata
;
clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
-fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
-fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
./bin/test -instr-profile=test.profdata

error: Failed to load coverage: Malformed profile data



test2.c: OK
=================#include <stdio.h>

static int foo() { return 42; }
int main() {
 return foo();
}
=================cp src/test2.c src/test.c; rm -fr default.profraw test.profdata
;
clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
-fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
-fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
./bin/test -instr-profile=test.profdata

/home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
       |    1|#include <stdio.h>
       |    2|
      1|    3|static int foo() { return 42; }
      1|    4|int main() {
      1|    5|  return foo();
      1|    6|}

test3.c: OK
=================#include <stdio.h>

int foo() { return 42; }
int main() {
 return 0;
}
=================cp src/test3.c src/test.c; rm -fr default.profraw test.profdata
;
clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
-fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
-fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
./bin/test -instr-profile=test.profdata

/home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
       |    1|#include <stdio.h>
       |    2|
      0|    3|int foo() { return 42; }
      1|    4|int main() {
      1|    5|  return 0;
      1|    6|}


As far I can understand issue somehow related to unused static functions.

Also, as I can track down the problem raised because of
lib/ProfileData/CoverageMappingReader.cpp (SectionData::get) expects
that function's names located inside __llvm_prf_names section but it
not true in case of test1.c, instead some function names located
inside .rodata section.


Is it known issue?
any hints, how to avoid or workaround it?

-- 
Be happy,
Best regards,
Dmitry Volyntsev

Dmitry Volyntsev <xeioexception at gmail.com>
writes:
> It seems I came across on issue with coverage mapping
> (http://www.llvm.org/docs/CoverageMappingFormat.html)
>
> check on:
> llvm revision: r228136
> clang  Last Changed Rev: 228121
> build: Debug+Asserts
> OS: ubuntu 14.04
>
>
> Here is simple snippets
>
> test1.c: NOT OK
> =================> #include <stdio.h>
>
> static int foo() { return 42; }
> int main() {
>  return 0;
> }
> =================> cp src/test1.c src/test.c; rm -fr default.profraw
test.profdata ;
> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
> ./bin/test -instr-profile=test.profdata
>
> error: Failed to load coverage: Malformed profile data
>
>
>
> test2.c: OK
> =================> #include <stdio.h>
>
> static int foo() { return 42; }
> int main() {
>  return foo();
> }
> =================> cp src/test2.c src/test.c; rm -fr default.profraw
test.profdata ;
> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
> ./bin/test -instr-profile=test.profdata
>
> /home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
>        |    1|#include <stdio.h>
>        |    2|
>       1|    3|static int foo() { return 42; }
>       1|    4|int main() {
>       1|    5|  return foo();
>       1|    6|}
>
> test3.c: OK
> =================> #include <stdio.h>
>
> int foo() { return 42; }
> int main() {
>  return 0;
> }
> =================> cp src/test3.c src/test.c; rm -fr default.profraw
test.profdata ;
> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
> ./bin/test -instr-profile=test.profdata
>
> /home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
>        |    1|#include <stdio.h>
>        |    2|
>       0|    3|int foo() { return 42; }
>       1|    4|int main() {
>       1|    5|  return 0;
>       1|    6|}
>
>
> As far I can understand issue somehow related to unused static functions.
It looks like this hits when a function isn't emitted by the frontend
but we emit an "empty" coverage map for it.
> Also, as I can track down the problem raised because of
> lib/ProfileData/CoverageMappingReader.cpp (SectionData::get) expects
> that function's names located inside __llvm_prf_names section but it
> not true in case of test1.c, instead some function names located
> inside .rodata section.
The problem is that these don't go through the InstrProfiling machinery,
so the names aren't lowered properly. I'd noticed a related issue not
long ago, but fixed a bug by inspection that happened to hide it
(r226764).

Feel free to file a bug (http://llvm.org/bugs/) and I'll to get this
fixed in the next day or two.

Here is the bug: http://llvm.org/bugs/show_bug.cgi?id=22531

On Tue, Feb 10, 2015 at 7:47 PM, Justin Bogner <mail at justinbogner.com>
wrote:
> Dmitry Volyntsev <xeioexception at gmail.com> writes:
>> It seems I came across on issue with coverage mapping
>> (http://www.llvm.org/docs/CoverageMappingFormat.html)
>>
>> check on:
>> llvm revision: r228136
>> clang  Last Changed Rev: 228121
>> build: Debug+Asserts
>> OS: ubuntu 14.04
>>
>>
>> Here is simple snippets
>>
>> test1.c: NOT OK
>> =================>> #include <stdio.h>
>>
>> static int foo() { return 42; }
>> int main() {
>>  return 0;
>> }
>> =================>> cp src/test1.c src/test.c; rm -fr
default.profraw test.profdata ;
>> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
>> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
>> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
>> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
>> ./bin/test -instr-profile=test.profdata
>>
>> error: Failed to load coverage: Malformed profile data
>>
>>
>>
>> test2.c: OK
>> =================>> #include <stdio.h>
>>
>> static int foo() { return 42; }
>> int main() {
>>  return foo();
>> }
>> =================>> cp src/test2.c src/test.c; rm -fr
default.profraw test.profdata ;
>> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
>> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
>> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
>> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
>> ./bin/test -instr-profile=test.profdata
>>
>> /home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
>>        |    1|#include <stdio.h>
>>        |    2|
>>       1|    3|static int foo() { return 42; }
>>       1|    4|int main() {
>>       1|    5|  return foo();
>>       1|    6|}
>>
>> test3.c: OK
>> =================>> #include <stdio.h>
>>
>> int foo() { return 42; }
>> int main() {
>>  return 0;
>> }
>> =================>> cp src/test3.c src/test.c; rm -fr
default.profraw test.profdata ;
>> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
>> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
>> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
>> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
>> ./bin/test -instr-profile=test.profdata
>>
>> /home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
>>        |    1|#include <stdio.h>
>>        |    2|
>>       0|    3|int foo() { return 42; }
>>       1|    4|int main() {
>>       1|    5|  return 0;
>>       1|    6|}
>>
>>
>> As far I can understand issue somehow related to unused static
functions.
>
> It looks like this hits when a function isn't emitted by the frontend
> but we emit an "empty" coverage map for it.
>
>> Also, as I can track down the problem raised because of
>> lib/ProfileData/CoverageMappingReader.cpp (SectionData::get) expects
>> that function's names located inside __llvm_prf_names section but
it
>> not true in case of test1.c, instead some function names located
>> inside .rodata section.
>
> The problem is that these don't go through the InstrProfiling
machinery,
> so the names aren't lowered properly. I'd noticed a related issue
not
> long ago, but fixed a bug by inspection that happened to hide it
> (r226764).
>
> Feel free to file a bug (http://llvm.org/bugs/) and I'll to get this
> fixed in the next day or two.


-- 
Be happy,
Best regards,
Dmitry Volyntsev

Here is probably a related bug: http://llvm.org/bugs/show_bug.cgi?id=22575

On Tue, Feb 10, 2015 at 7:47 PM, Justin Bogner <mail at justinbogner.com>
wrote:
> Dmitry Volyntsev <xeioexception at gmail.com> writes:
>> It seems I came across on issue with coverage mapping
>> (http://www.llvm.org/docs/CoverageMappingFormat.html)
>>
>> check on:
>> llvm revision: r228136
>> clang  Last Changed Rev: 228121
>> build: Debug+Asserts
>> OS: ubuntu 14.04
>>
>>
>> Here is simple snippets
>>
>> test1.c: NOT OK
>> =================>> #include <stdio.h>
>>
>> static int foo() { return 42; }
>> int main() {
>>  return 0;
>> }
>> =================>> cp src/test1.c src/test.c; rm -fr
default.profraw test.profdata ;
>> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
>> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
>> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
>> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
>> ./bin/test -instr-profile=test.profdata
>>
>> error: Failed to load coverage: Malformed profile data
>>
>>
>>
>> test2.c: OK
>> =================>> #include <stdio.h>
>>
>> static int foo() { return 42; }
>> int main() {
>>  return foo();
>> }
>> =================>> cp src/test2.c src/test.c; rm -fr
default.profraw test.profdata ;
>> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
>> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
>> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
>> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
>> ./bin/test -instr-profile=test.profdata
>>
>> /home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
>>        |    1|#include <stdio.h>
>>        |    2|
>>       1|    3|static int foo() { return 42; }
>>       1|    4|int main() {
>>       1|    5|  return foo();
>>       1|    6|}
>>
>> test3.c: OK
>> =================>> #include <stdio.h>
>>
>> int foo() { return 42; }
>> int main() {
>>  return 0;
>> }
>> =================>> cp src/test3.c src/test.c; rm -fr
default.profraw test.profdata ;
>> clang -c -o obj/test.o src/test.c -I -g -O0 -fprofile-instr-generate
>> -fcoverage-mapping; clang -o bin/test obj/test.o -I -g -O0
>> -fprofile-instr-generate -fcoverage-mapping; ./bin/test ;
>> llvm-profdata merge -o test.profdata default.profraw; llvm-cov show
>> ./bin/test -instr-profile=test.profdata
>>
>> /home/xeioex/workspace/clang/experiments/llvm-cov/test/src/test.c:
>>        |    1|#include <stdio.h>
>>        |    2|
>>       0|    3|int foo() { return 42; }
>>       1|    4|int main() {
>>       1|    5|  return 0;
>>       1|    6|}
>>
>>
>> As far I can understand issue somehow related to unused static
functions.
>
> It looks like this hits when a function isn't emitted by the frontend
> but we emit an "empty" coverage map for it.
>
>> Also, as I can track down the problem raised because of
>> lib/ProfileData/CoverageMappingReader.cpp (SectionData::get) expects
>> that function's names located inside __llvm_prf_names section but
it
>> not true in case of test1.c, instead some function names located
>> inside .rodata section.
>
> The problem is that these don't go through the InstrProfiling
machinery,
> so the names aren't lowered properly. I'd noticed a related issue
not
> long ago, but fixed a bug by inspection that happened to hide it
> (r226764).
>
> Feel free to file a bug (http://llvm.org/bugs/) and I'll to get this
> fixed in the next day or two.


-- 
Be happy,
Best regards,
Dmitry Volyntsev