• realhet (12/12) Sep 28 Hi,
• user1234 (13/25) Sep 28 Speaking of speculation... "-allinst" disable an internal system
• realhet (12/12) Sep 28 Thank You!

realhet <real_het hotmail.com> writes:

Hi,

I have some statements in my mind about --allinst, but I'm not 
sure they are correct or not.

1. Normally the compiler analyzes the full code with all the 
modules, and it only compiles code for template things that are 
used in the given code.

2. It is not needed for compiling the code with a single compiler 
instance, but is required for projects that are compiled in 
parallel by using multiple compiler instances.

Please someone tell me that these statements are valid or I know 
this wrong.  (These are just my speculations, feelings, I didn't 
find documentation on this.)

user1234 <user1234 12.de> writes:

On Saturday, 28 September 2024 at 12:20:43 UTC, realhet wrote:
 Hi,

 I have some statements in my mind about --allinst, but I'm not 
 sure they are correct or not.

 1. Normally the compiler analyzes the full code with all the 
 modules, and it only compiles code for template things that are 
 used in the given code.

 2. It is not needed for compiling the code with a single 
 compiler instance, but is required for projects that are 
 compiled in parallel by using multiple compiler instances.

 Please someone tell me that these statements are valid or I 
 know this wrong.  (These are just my speculations, feelings, I 
 didn't find documentation on this.)

Speaking of speculation... "-allinst" disable an internal system 
of speculation that is: "this instance is already emitted so dont 
do it again".

Over the years it has appeared that the speculation does not 
always work as it should.

The classic symptom of that is when people encounter linker 
errors related to missing symbols. "-allinst" is the number one 
workaround. When activated, it's likely that things get emitted 
more than once, but at least, speculation bugs are gone.

You may ask "but then there should be other linker errors about 
double definition ?". No, those syms has to be emitted as "weak" 
symbols, so the linker ignore duplicated definitions.

realhet <real_het hotmail.com> writes:

Thank You!

I just did a test, I did not used the --allinst flag for the 
first time since 4-5 years.
It was a superstition since that, because back then it fixed 
something.

Now to my surprise the test build was successful :D
80KLOC, 20 modules -> 20 obj files, and the full compiling time 
went from 120 sec down to 107 sec.  The exe started without any 
problems.

Hopefully my other project will run too.

So from now on I will only use --allinst again if I get linker 
errors in the future.