Date: Tue, 20 Nov 2001 20:06:23 +0800 (CST) From: freebsd@hoolan.org To: freebsd-hackers@freebsd.org Subject: c++ compiler allocates uninitialized global variable in .data section Message-ID: <Pine.BSF.4.05.10111162100300.28821-100000@hoolan.org>
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I found that c++ compiler (4.4-RELEASE) allocates uninitialized global
variable in the data section instead of the bss section. Here is my
code sample (b.cpp):
char aa[1024*1024*10];
void f(void)
{
}
after c++ -c b.cpp I get a nearly 10MB object file, whereas on linux
(RedHat 7.2, gcc-2.96-98) it produces a file less than 1kB. So I
assemble it to find the diffenece.
on FreeBSD:
.globl aa
.data
.p2align 5
.type aa,@object
.size aa,10485760
aa:
.zero 10485760
but on Linux:
.globl aa
.bss
.align 32
.type aa,@object
.size aa,10485760
aa:
.zero 10485760
In consequence, that's why I get a huge object file with FreeBSD c++.
Is this behavior of c++ correct? I suppose uninitialized data should
goes to .bss section according to elf(5).
Regards,
Jeffrey Tang
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