http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48481
Summary: C++ overloading memory hog Product: gcc Version: 4.6.0 Status: UNCONFIRMED Keywords: memory-hog Severity: normal Priority: P3 Component: c++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: ja...@gcc.gnu.org CC: ja...@gcc.gnu.org #define A(n) \ struct S##n { int i; }; \ S##n v##n;\ extern int foo (S##n, S##n);\ extern void bar (S##n); #define B(n) A(n##0) A(n##1) A(n##2) A(n##3) A(n##4) A(n##5) A(n##6) A(n##7) A(n##8) A(n##9) #define C(n) B(n##0) B(n##1) B(n##2) B(n##3) B(n##4) B(n##5) B(n##6) B(n##7) B(n##8) B(n##9) #define D(n) C(n##0) C(n##1) C(n##2) C(n##3) C(n##4) C(n##5) C(n##6) C(n##7) C(n##8) C(n##9) #ifndef N #define N 10000 #endif #if N == 1000 #define E(n) D(n##0) #elif N == 2000 #define E(n) D(n##0) D(n##1) #elif N == 3000 #define E(n) D(n##0) D(n##1) D(n##2) #else #define E(n) D(n##0) D(n##1) D(n##2) D(n##3) D(n##4) D(n##5) D(n##6) D(n##7) D(n##8) D(n##9) #endif E(0) void foo () { #undef A #define A(n) if (foo (v##n, v##n)) bar (v##n); E(0) } testcase eats huge amounts of memory. With -DN=1000 -O0 it compiles quickly, using 432768 kB of memory (852MB in top), with -DN=2000 -O0 it already uses 1672544 kB (3.5GB in top). With -DN=3000 it took around 8GB in top. In --enable-gather-detailed-mem-stats -fmem-report, for N=1000 I see: cp/tree.c:1447 (ovl_cons) 64032000:15.1% 0: 0.0% 256032: 1.8% 0: 0.0% 2009001 c-family/c-common.c:9556 (make_tree_vector) 159840120:37.8% 0: 0.0% 0: 0.0% 0: 0.0% 3996003 cp/search.c:1135 (build_baselink) 191952000:45.4% 0: 0.0% 0: 0.0% 0: 0.0% 3999000 Total 422660566 8986384 14294815 2724053 10281399 source location Garbage Freed Leak Overhead Times and for N=2000: cp/tree.c:1447 (ovl_cons) 256064000:15.3% 0: 0.0% 512032: 1.9% 0: 0.0% 8018001 c-family/c-common.c:9556 (make_tree_vector) 639680120:38.1% 0: 0.0% 0: 0.0% 0: 0.0% 15992003 cp/search.c:1135 (build_baselink) 767904000:45.8% 0: 0.0% 0: 0.0% 0: 0.0% 15998000 Total 1677099246 12464328 27061439 3876781 40545425 source location Garbage Freed Leak Overhead Times