Can you try it out on canister p5ezj-diaaa-aaaag-acn5a-cai ?
You can check on:
- icp:public cdk:name →
icpp - icp:public cdk:languages →
c++ - icp:private icpp:compiler →
3.14.1
The command $ icpp build-wasm will now automatically add those custom sections to the wasm, using the already installed tool llvm-objcopy, which comes with wasi-sdk, which is what icpp-pro is build on top off.
In summary, with icpp-pro 3.14.1, the following commands are now run automatically as part of the build-wasm pipeline, and it works on Windows, Ubuntu and Mac:
--
Adding custom sections to the wasm file...
~/.icpp/wasi-sdk-20.0/bin/llvm-objcopy --add-section="icp:public candid:service"="/home/demo/greet/src/greet.did" greet.wasm greet.wasm
~/.icpp/wasi-sdk-20.0/bin/llvm-objcopy --add-section="icp:public cdk:name"="/home/demo/greet/build/custom_section_cdk_name.txt" greet.wasm greet.wasm
~/.icpp/wasi-sdk-20.0/bin/llvm-objcopy --add-section="icp:public cdk:languages"="/home/demo/greet/build/custom_section_cdk_languages.txt" greet.wasm greet.wasm
~/.icpp/wasi-sdk-20.0/bin/llvm-objcopy --add-section="icp:private icpp:compiler"="/home/demo/greet/build/custom_section_version.txt" greet.wasm greet.wasm
--
You can then verify the content of the custom sections using the llvm-objdump command:
# check 1
$ ~/.icpp/wasi-sdk-20.0/bin/llvm-objdump -h build/greet.wasm
build/greet.wasm: file format wasm
Sections:
Idx Name Size VMA Type
Idx Name Size VMA Type
0 TYPE 0000013a 00000000
1 IMPORT 000000d8 00000000
2 FUNCTION 000008e9 00000000
3 TABLE 00000007 00000000
4 MEMORY 00000003 00000000
5 GLOBAL 000006c3 00000000
6 EXPORT 000047f1 00000000
7 ELEM 00000869 00000000
8 CODE 000b6ba4 00000000 TEXT
9 DATA 0000b21e 00000000 DATA
10 icp:public candid:service 00000282 00000000
11 icp:public cdk:name 00000004 00000000
12 icp:public cdk:languages 00000003 00000000
13 icp:private icpp:compiler 00000006 00000000
# With values for each section
$ ~/.icpp/wasi-sdk-20.0/bin/llvm-objdump --full-contents --section='icp:private icpp:compiler' build/greet.wasm
build/greet.wasm: file format wasm
Contents of section icp:private icpp:compiler:
0000 332e3133 2e30 3.14.1
$ ~/.icpp/wasi-sdk-20.0/bin/llvm-objdump --full-contents --section='icp:public cdk:name' build/greet.wasm
build/greet.wasm: file format wasm
Contents of section icp:public cdk:name:
0000 69637070 icpp
$ ~/.icpp/wasi-sdk-20.0/bin/llvm-objdump --full-contents --section='icp:public cdk:languages' build/greet.wasm
build/greet.wasm: file format wasm
Contents of section icp:public cdk:languages:
0000 632b2b c++
Reason I decided to go with this approach is because of what I saw in the motoko wasm:
# check 1
$ llvm-objdump -h my_motoko.wasm
my_motoko.wasm: file format wasm
Sections:
Idx Name Size VMA Type
0 TYPE 000000c8 00000000
1 IMPORT 0000026f 00000000
2 FUNCTION 00000378 00000000
3 TABLE 00000007 00000000
4 MEMORY 00000003 00000000
5 GLOBAL 00000084 00000000
6 EXPORT 000001d3 00000000
7 START 00000002 00000000
8 ELEM 0000077c 00000000
9 CODE 00028e65 00000000 TEXT
10 DATA 00011541 00000000 DATA
11 name 0000661d 00000000
12 icp:public candid:service 0000047c 00000000
13 icp:private motoko:stable-types 0000004f 00000000
14 icp:private motoko:compiler 00000005 00000000
15 icp:public candid:args 00000009 00000000
# Check 2
$ llvm-objdump --full-contents --section='icp:private motoko:compiler' my_motoko.wasm
my_motoko.wasm: file format wasm
Contents of section icp:private motoko:compiler:
0000 302e392e 38 0.9.8
After seeing what’s in the Motoko wasm, I decided to just do both, and I implemented @lastmjs suggestion for name & languagues, but then the motoko convention for version number.
ps. one great side effect of this effort is that I learned how to stuff the candid file into the wasm using llvm-objcopy, and when I deploy, the Candid UI now works!
@lwshang ,
If dfx will support these metadatas as part of a standard, I will switch to that implementation for consistency.