1 ------------------------------------------------------------------- 2 Guide to multiple architecture support 3 ------------------------------------------------------------------- 4 5 What is achieved 6 ~~~~~~~~~~~~~~~~ 7 Valgrind supports systems where binaries for more than one 8 architecture can be run. The current arrangements build: 9 10 - single-arch support on x86 and ppc32 systems 11 - dual-arch support on amd64 and ppc64 systems 12 13 To support this the valgrind build system can now build multiple 14 versions of the coregrind library and of VEX, and then build and link 15 multiple versions of each tool. 16 17 A central notion is that of 'primary' vs 'secondary' platforms. The 18 system is built in its entirety for the primary platform, including 19 performance and regression suites and all auxiliary programs. For 20 dual-arch systems, the primary platform is amd64 and ppc64 21 respectively. 22 23 On dual-arch systems, there is a 'secondary' target - x86 and ppc32 24 respectively. The tools are built again for the secondary target, and 25 the 'valgrind' launcher program can handle executables for either the 26 primary or secondary target. However, the regression and performance 27 tests and everything else is not rebuilt for the secondary target. 28 29 On single-arch systems, there is no secondary target. 30 31 32 How the build system does that 33 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 34 The keys to understanding this are in: 35 36 - configure.in 37 - Makefile.flags.am 38 - <tool>/tests/Makefile.am 39 - <tool>/tests/<arch>/Makefile.am 40 - perf/Makefile.am 41 42 The configure script inspects the CPU. It then sets 43 44 VGCONF_PLATFORM_PRI_CAPS to be the primary target 45 VGCONF_PLATFORM_SEC_CAPS to be the secondary target, if any 46 47 It also sets one (single-arch build) or two (dual-arch build) of 48 the following: 49 50 VGCONF_PLATFORMS_INCLUDE_X86_LINUX 51 VGCONF_PLATFORMS_INCLUDE_AMD64_LINUX 52 VGCONF_PLATFORMS_INCLUDE_PPC32_LINUX 53 VGCONF_PLATFORMS_INCLUDE_PPC64_LINUX 54 ... 55 56 On an amd64 system both VGCONF_PLATFORMS_INCLUDE_X86_LINUX and 57 VGCONF_PLATFORMS_INCLUDE_AMD64_LINUX will be true so that two versions of 58 all the tools will be built. Similarly on a ppc64 system both 59 VGCONF_PLATFORMS_INCLUDE_PPC32_LINUX and 60 VGCONF_PLATFORMS_INCLUDE_PPC64_LINUX will be defined (unless 61 --enable-only32bit or --enable-only64bit is used). For the amd64 example, 62 the coregrind libraries will be named: 63 64 libcoregrind_x86_linux.a 65 libcoregrind_amd64_linux.a 66 67 and the VEX libraries: 68 69 libvex_x86_linux.a 70 libvex_amd64_linux.a 71 72 Each tool will then be built twice, along with any preload library 73 for the tool and the core preload libraries. At install time one 74 subdirectory will be created in the valgrind library directory for 75 each supported platforms and the tools and shared objects will be 76 installed in the appropriate place. On amd64 the result will be: 77 78 <prefix>/lib/valgrind 79 <prefix>/lib/valgrind/default.supp 80 <prefix>/lib/valgrind/glibc-2.4.supp 81 <prefix>/lib/valgrind/hp2ps 82 <prefix>/lib/valgrind/amd64-linux 83 <prefix>/lib/valgrind/amd64-linux/vgpreload_core.so 84 <prefix>/lib/valgrind/amd64-linux/vgpreload_massif.so 85 <prefix>/lib/valgrind/amd64-linux/cachegrind 86 <prefix>/lib/valgrind/amd64-linux/memcheck 87 <prefix>/lib/valgrind/amd64-linux/helgrind 88 <prefix>/lib/valgrind/amd64-linux/massif 89 <prefix>/lib/valgrind/amd64-linux/vgpreload_memcheck.so 90 <prefix>/lib/valgrind/amd64-linux/lackey 91 <prefix>/lib/valgrind/amd64-linux/none 92 <prefix>/lib/valgrind/amd64-linux/vgpreload_helgrind.so 93 <prefix>/lib/valgrind/xfree-3.supp 94 <prefix>/lib/valgrind/x86-linux 95 <prefix>/lib/valgrind/x86-linux/vgpreload_core.so 96 <prefix>/lib/valgrind/x86-linux/vgpreload_massif.so 97 <prefix>/lib/valgrind/x86-linux/cachegrind 98 <prefix>/lib/valgrind/x86-linux/memcheck 99 <prefix>/lib/valgrind/x86-linux/helgrind 100 <prefix>/lib/valgrind/x86-linux/massif 101 <prefix>/lib/valgrind/x86-linux/vgpreload_memcheck.so 102 <prefix>/lib/valgrind/x86-linux/lackey 103 <prefix>/lib/valgrind/x86-linux/none 104 <prefix>/lib/valgrind/x86-linux/vgpreload_helgrind.so 105 <prefix>/lib/valgrind/glibc-2.3.supp 106 <prefix>/lib/valgrind/xfree-4.supp 107 <prefix>/lib/valgrind/glibc-2.2.supp 108 109 The launcher program (ie the valgrind binary itself) is always built 110 as a program for the primary target (so a 64 bit program on amd64 and 111 ppc64) but will peek at the program which it is being asked to run and 112 decide which of the possible tools to run taking both the requested 113 tool and the format of the program being run into account. 114 115 Because the execv system call is now routed back through the launcher 116 it is also possible to exec an x86 program from an amd64 program and 117 vice versa. Ditto ppc32 and ppc64. 118 119 120 Rules for Makefile.am hacking 121 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 122 In places where compilation should happen twice (on a dual-arch 123 system), the decision about which directories and flags to use is 124 guarded by the VGCONF_PLATFORMS_INCLUDE_* symbols. 125 126 But there are also places where building must only happen once, 127 for the primary architecture. These places are (at least): 128 129 * the launcher, valgrind.c 130 * all the architecture-independent regression tests 131 * the performance tests 132 * optionally, auxilary programs like hp2ps and valgrind-listener 133 134 In order to do that, we need to know what flags to use to build for 135 the primary target, and in particular whether to hand -m32 or -m64 to 136 gcc. This is where Makefile.flags.am comes in. 137 138 At the bottom of that file are defined AM_CPPFLAGS_PRI, AM_CFLAGS_PRI 139 and AM_CCASFLAGS_PRI that must be used for compiling for the primary 140 architecture. For example, look in coregrind/Makefile.am, and you 141 will see these flag-sets being used to build the launcher (valgrind). 142 143 Also at the bottom of Makefile.flags.am, AM_FLAG_M3264_PRI is defined. 144 This gives the -m32/-m64 flag needed to build for the primary target. 145 That flag is also contained within AM_CFLAGS_PRI -- AM_FLAG_M3264_PRI 146 merely facilitates getting hold of it without the surrounding gunk. 147 148 This leads to the final complication: building the regression tests. 149 Most of them are architecture-neutral and so should be built for the 150 primary target. The /test/ Makefile.am's duly include 151 AM_FLAG_M3264_PRI in the compilation invokations, and you should 152 ensure you preserve that when adding more tests. 153 154 However, there are some arch-specific test directories (eg, 155 none/tests/ppc32, etc). In each of these, we implicitly 'know' 156 whether -m32 or -m64 is the right thing to specify. So instead of 157 messing with AM_FLAG_M3264_PRI, these directories merely specific 158 @FLAG_M32@ or @FLAG_M64@ directly. (These two symbols are also 159 automagically set up by configure.in. Do not use -m32 and -m64 160 directly - older compilers barf on them). Another reason not to 161 use -m32 and -m64 directly is that they are called -maix32 and 162 -maix64 on AIX; once again this is taken care of properly if you 163 use @FLAG_M32@ and @FLAG_M64@ instead. 164
