• Cecil Ward (12/12) Mar 30 2018 Say that I use say GDC or LDC. I want to declare a routine as
• Johan Engelen (16/28) Mar 30 2018 Global functions in a module have default "public" visibility
• Kagamin (6/11) Mar 31 2018 If you compile for lto, ldc compiles code to IR and linker

Cecil Ward <d cecilward.com> writes:

Say that I use say GDC or LDC. I want to declare a routine as 
public in one compilation unit (.d src file) and be able to 
access it from other compilation units.

Do I simply declare the routine with the word keyword public 
before the usual declaration?

Or maybe that is the default, like not using the keyword static 
with function declarations in C?

My principal question: If I successfully do this, with GCC or 
LDC, will I be able to get the code for the externally defined 
short routine expanded inline and fully integrated into the 
generated code that corresponds to the calling source code? (So 
no ‘call’ instruction is even found.)

Johan Engelen <j j.nl> writes:

On Friday, 30 March 2018 at 10:23:15 UTC, Cecil Ward wrote:
 Say that I use say GDC or LDC. I want to declare a routine as 
 public in one compilation unit (.d src file) and be able to 
 access it from other compilation units.

 Do I simply declare the routine with the word keyword public 
 before the usual declaration?

 Or maybe that is the default, like not using the keyword static 
 with function declarations in C?

Global functions in a module have default "public" visibility 
indeed.
https://dlang.org/spec/attribute.html#visibility_attributes

 My principal question: If I successfully do this, with GCC or 
 LDC, will I be able to get the code for the externally defined 
 short routine expanded inline and fully integrated into the 
 generated code that corresponds to the calling source code? (So 
 no ‘call’ instruction is even found.)

What you want is "cross-module inlining".
As far as I know, DMD and GDC will do cross-module inlining (if 
inlining is profitable).

LDC does not, unless `-enable-cross-module-inlining` is enabled 
(which is aggressive and may result in linking errors in specific 
cases, https://github.com/ldc-developers/ldc/pull/1737).
LDC with LTO enabled will definitely give you cross-module 
inlining (also for private functions).

You can force inlining with `pragma(inline, true)`, but it is 
usually better to leave that decision up to the compiler.
https://dlang.org/spec/pragma.html#inline

-Johan

Kagamin <spam here.lot> writes:

On Friday, 30 March 2018 at 10:23:15 UTC, Cecil Ward wrote:
 My principal question: If I successfully do this, with GCC or 
 LDC, will I be able to get the code for the externally defined 
 short routine expanded inline and fully integrated into the 
 generated code that corresponds to the calling source code? (So 
 no ‘call’ instruction is even found.)

If you compile for lto, ldc compiles code to IR and linker 
generates machine code from IR with inlining, at the IR level 
most information about source code is lost, only the actual code 
remains, declarations are purely source code items. But it only 
inline IR code, machine code can't be inlined.