[llvm-dev] Fwd: about clang compile c to wasm lost argument

[shankusu2017 via llvm-dev]

---------- Forwarded message ---------
发件人： shankusu2017 <shankusu2017 at gmail.com>
Date: 2021年12月19日周日 18:17
Subject: Fwd: about clang compile c to wasm lost argument
To: <llvm-admin at lists.llvm.org>




---------- Forwarded message ---------
发件人： shankusu2017 <shankusu2017 at gmail.com>
Date: 2021年12月19日周日 18:15
Subject: about clang compile c to wasm lost argument
To: <surma at surma.dev>


hi:
   I use clang to compile the c code into wasm, and I found that clang13/14
regards the variable reference in the c language as a parameter, such as
the "..." part in int printf(const char *format, ...); In this way, when I
implemented my own printf function in the host environment, wasm only
passed 2 parameters to the host when calling prinf, but I actually passed
more than 2 parameters. This will cause the printf function I implemented
by myself to receive only 2 parameters, and thus lose one parameter. The
attachment contains my original c code and compiled wasm and wat codes. The
green box part shows that the printf function only accepts 2 input
parameters. I don't know how to make clang understand that the number of
parameters received by printf is uncertain. Is there any solution?
   follow build cmd:
clang -I ../../src/ --target=wasm32 -nostdlib  -Wl,--no-entry
-Wl,--export-all -Wl,--allow-undefined --sysroot=/usr printf.c -o
../.././build/printf.wasm
wabt

wasm2wat printf.wasm -o printf.wat
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