GCC Plugins - CC1 - Multiple processes on PLUGIN_FINISH_TYPE
Hi all, I've been working on a plugin that processes some data. My plugin grabs some data from the tree. I'm trying to understand a certain "weird" behaviour I am seeing. And yeah, I'm new to the mailing list and gcc's innards! Be forgiving! :) I appreciate the help! When I add: register_callback (BaseName, PLUGIN_FINISH_TYPE, CinsGcc_CB_Type, NULL); The plugin appears to be loaded by a 2nd process, initialized, and provided with what appears to be much the same data (at least from my view). Other plugin events do not appear to cause this behaviour. The command line is.., gcc -fplugin=./out/cins.so -c -o ./out/tests/test_0.o test/test_0.c \ -fplugin-arg-cins-error=./out/tests/test_0.o_err.txt \ -fplugin-arg-cins-output=./out/tests/test_0.o_out.txt The extended log file written to disk says: (001E:31D1) INFO src/plugin/gcc_core.c:0092 plugin_init CINS silencing console now. The console says: CINS silencing console now. 31D1 and 31CD are different PIDs. 001E is the identifier indicating the log count (i.e. there were 0x1E prints that came before) As well, __progname == 'cc1'. gcc -v: Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.6.1/lto-wrapper Target: i686-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.6.1-9ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++,go --prefix=/usr --program-suffix=-4.6 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin --enable-objc-gc --enable-targets=all --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu Thread model: posix gcc version 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3)
Re: GCC Plugins - CC1 - Multiple processes on PLUGIN_FINISH_TYPE
Ah! I see what might be happening. I was using assert(0) in the callback to stop the program's execution (to examine the output at that location). When I do this, I get the funky results. (I was surprised it was seen as HTML seeing as it was sent from my blackberry (no html e-mail editing). The content type claimed text/plain.) On Wed, Apr 25, 2012 at 7:23 AM, Diego Novillo wrote: > [ Please do not send html mail. It will be rejected by the list server. ] > > On Wed, Apr 25, 2012 at 10:16, wrote: > >> That much I understand. But it's cc1 that is in two processes, and gcc -v >> only shows it being invoked once. Finally the output on stderr is only from >> one of the two processes. > > cc1 is just one process. You will need to show us the output of 'gcc -v'. > > >> (To clarify terminology: gcc app being the driver here? I didn't think the >> plugins were loaded in the 'gcc' driver? Strictly from the compiler?) > > They are not. They are loaded by cc1. > > > Diego.
Traversing trees in a plugin...
Hi all, I'm working on a GCC plugin, having made a lot of progress on that front. So far running my plugin works 'more or less' on things like the linux kernel. On the other hand running it on the plugin itself causes problems. Given that some of the data structures are pretty complicated in GCC I'm not surprised. So the question I have (w.r.t. TREE data structures) are: 1) How to marking a node as visited by my algorithm (without screwing up the compiler!) 2) How to associate additional data (perhaps a pointer to something else) to a node (like a unique identifier, or a pointer to a data structure). Thoughts: 1) The general overview of my current algorithm: a) When a node can be uniquely identified (has an identifier or position information) I can use a look up. b) However with types (especially those that are anonymous) I find it challenging to do so. I assign such a node an anonymous identifier or try to assign a general data type (i.e. integer) when the type is internal. c) When I arrive at a node and it is identifiable and it is found in the lookup table I can infer that its children have also been visited. d) However there may be cases when I cannot identify where a node has been visited, and processing is duplicated. e) This method seems quite inefficient, error prone. 2) Can memory addresses be used to uniquely identify nodes? I believe this may be the case for identifier nodes. 3) Other ideas? I tuned my process based on trial and error, and focused on what worked at the time. I think I'm doing it in the wrong way. Brett
Re: Traversing trees in a plugin...
On Sat, Jun 2, 2012 at 11:31 AM, Basile Starynkevitch wrote: > In the MELT meta-plugin (recall that MELT is a high-level domain specific > language to > extend GCC, see http://gcc-melt.org/ for more) we extensively use associative > hash-tables > for that. MELT offers homogeneous hash-tables, e.g. hash-table associating > tree (i.e. > non-null tree pointers) to arbitrary non-null MELT values (e.g. MELT > closures, or MELT > lists, or MELT objects, etc etc), or hash-table associating (non null) gimple > to non > null MELT values. > > So you can have e.g. an hash-table associating each tree (every tree is in > GCC a non-null > pointer to a structure) with data associated to it. Once it has some data you > know that > this tree has been visited. I'll poke around the MELT source code - In Melt, where in source code may I have a look to see how trees and mapped to the hash table? Are you able to summarize the basics? I.e. the hash for a specific node tree is derived from what data? Pointer address? Thanks for the info.
