From 907b0a371abe92b3314612faea0b3d68e048c156 Mon Sep 17 00:00:00 2001 From: Robert Hensing Date: Tue, 23 Jul 2024 16:02:40 +0200 Subject: [PATCH 1/2] Rename osStackLow -> osStackLimit This is in accordance with ARM's naming convention. "Low" is confusing, because it could refer to either the cold end of the stack as an abstract data type, or a low address. These are different places, because the stack grows down through the address space. --- src/libexpr/eval-gc.cc | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/src/libexpr/eval-gc.cc b/src/libexpr/eval-gc.cc index 73ab809e5..75368c5ac 100644 --- a/src/libexpr/eval-gc.cc +++ b/src/libexpr/eval-gc.cc @@ -86,12 +86,13 @@ void fixupBoehmStackPointer(void ** sp_ptr, void * _pthread_id) auto pthread_id = reinterpret_cast(_pthread_id); pthread_attr_t pattr; size_t osStackSize; - void * osStackLow; + // The low address of the stack, which grows down. + void * osStackLimit; void * osStackBase; # ifdef __APPLE__ osStackSize = pthread_get_stacksize_np(pthread_id); - osStackLow = pthread_get_stackaddr_np(pthread_id); + osStackLimit = pthread_get_stackaddr_np(pthread_id); # else if (pthread_attr_init(&pattr)) { throw Error("fixupBoehmStackPointer: pthread_attr_init failed"); @@ -110,18 +111,18 @@ void fixupBoehmStackPointer(void ** sp_ptr, void * _pthread_id) # else # error "Need one of `pthread_attr_get_np` or `pthread_getattr_np`" # endif - if (pthread_attr_getstack(&pattr, &osStackLow, &osStackSize)) { + if (pthread_attr_getstack(&pattr, &osStackLimit, &osStackSize)) { throw Error("fixupBoehmStackPointer: pthread_attr_getstack failed"); } if (pthread_attr_destroy(&pattr)) { throw Error("fixupBoehmStackPointer: pthread_attr_destroy failed"); } # endif - osStackBase = (char *) osStackLow + osStackSize; + osStackBase = (char *) osStackLimit + osStackSize; // NOTE: We assume the stack grows down, as it does on all architectures we support. // Architectures that grow the stack up are rare. - if (sp >= osStackBase || sp < osStackLow) { // lo is outside the os stack - sp = osStackLow; + if (sp >= osStackBase || sp < osStackLimit) { // lo is outside the os stack + sp = osStackLimit; } } From 68693276f9c5829489132c1f5a142717da84f44a Mon Sep 17 00:00:00 2001 From: Robert Hensing Date: Tue, 23 Jul 2024 16:27:26 +0200 Subject: [PATCH 2/2] Update fixupBoehmStackPointer doc lo might have made sense in the bdwgc code, maybe?, but not here. --- src/libexpr/eval-gc.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/libexpr/eval-gc.cc b/src/libexpr/eval-gc.cc index 75368c5ac..ba19cd74e 100644 --- a/src/libexpr/eval-gc.cc +++ b/src/libexpr/eval-gc.cc @@ -121,7 +121,7 @@ void fixupBoehmStackPointer(void ** sp_ptr, void * _pthread_id) osStackBase = (char *) osStackLimit + osStackSize; // NOTE: We assume the stack grows down, as it does on all architectures we support. // Architectures that grow the stack up are rare. - if (sp >= osStackBase || sp < osStackLimit) { // lo is outside the os stack + if (sp >= osStackBase || sp < osStackLimit) { // sp is outside the os stack sp = osStackLimit; } }