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It might be a simple one but I have this question bothering me for sometime.
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hi,
can we install gcc compiler in unix based OS(sun solar,IBM AIX,HP,etc) and also
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regards
Ajay (3 Replies)
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Hi,
we are converting from IBM-AIX(xl c/c++ compiler) to Linux(GCC complier).
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:confused: I have a question concerning gcc. IŽd like to install the gcc on my Mac OS X, but when I try to run the configure command I get the following message:
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ERROR::DWARF(7stap) ERROR::DWARF(7stap)
NAME
error::dwarf - dwarf debuginfo quality problems
DESCRIPTION
Systemtap sometimes relies on ELF/DWARF debuginfo for programs being instrumented to locate places to probe, or context variables to
read/write, just like a symbolic debugger does. Even though examination of the program's source code may show variables or lines where
probes may be desired, the compiler must preserve information about them for systemtap (or a debugger such as gdb) to get pinpoint access
to the desired information. If a script requires such data, but the compiler did not preserve enough of it, pass-2 errors may result.
Common conditions that trigger these problems include;
compiler version
Prior to GCC version 4.5, debuginfo quality was fairly limited. Often developers were advised to build their programs with -O0 -g
flags to disable optimization. GCC version 4.5 introduced a facility called "variable-tracking assignments" that allows it to gen-
erate high-quality debuginfo under full -O2 -g optimization. It is not perfect, but much better than before. Note that, due to
another gcc bug (PR51358) -O0 -g can actually sometimes make debuginfo quality worse than for -O2 -g.
function inlining
Even modern gcc sometimes has problems with parameters for inlined functions. It may be necessary to change the script to probe at
a slightly different place (try a .statement() probe, instead of a .function() probe, somewhere a few source lines into the body of
the inlined function. Or try putting a probe at the call site of the inlined function. Or use the if @defined($var) { ... } script
language construct to test for the resolvability of the context variable before using it.
instruction reordering
Heavily optimized code often smears the instructions from multiple source statements together. This can leave systemtap with no
place to choose to place a probe, especially a statement probe specified by line number. Systemtap may advise to try a nearby line
number, but these may not work well either. Consider placing a probe by a statement wildcard or line number range.
ALTERNATIVES
In order to reduce reliance on ELF/DWARF debuginfo, consider the use of statically compiled-in instrumentation, such as kernel tracepoints,
or <sys/sdt.h> userspace markers. Such instrumentation hook sites are relatively low cost (just one NOP instruction for sdt.h), and nearly
guarantee the availability of parameter data and a reliable probe site, all without reliance on debuginfo.
SEE ALSO
stap(1),
http://dwarfstd.org/,
http://sourceware.org/systemtap/wiki/TipContextVariables,
http://gcc.gnu.org/wiki/Var_Tracking_Assignments,
warning::debuginfo(7stap),
error::reporting(7stap)
ERROR::DWARF(7stap)