From 91ddba836c22cb95fef94a422d8dc573591eb4ae Mon Sep 17 00:00:00 2001 From: Keith Seitz Date: Wed, 26 Jan 2022 08:56:18 -0800 Subject: [PATCH] Reference array of structs instead of first member during memcpy MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit aarch64-tdep.c defines the following macro: #define MEM_ALLOC(MEMS, LENGTH, RECORD_BUF) \ do \ { \ unsigned int mem_len = LENGTH; \ if (mem_len) \ { \ MEMS = XNEWVEC (struct aarch64_mem_r, mem_len); \ memcpy(&MEMS->len, &RECORD_BUF[0], \ sizeof(struct aarch64_mem_r) * LENGTH); \ } \ } \ while (0) This is simlpy allocating a new array and copying it. However, for the destination address, it is actually copying into the first member of the first element of the array (`&MEMS->len"). This elicits a warning with GCC 12: ../../binutils-gdb/gdb/aarch64-tdep.c: In function ‘int aarch64_process_record(gdbarch*, regcache*, CORE_ADDR)’: ../../binutils-gdb/gdb/aarch64-tdep.c:3711:23: error: writing 16 bytes into a region of size 8 [-Werror=stringop-overflow=] 3711 | memcpy(&MEMS->len, &RECORD_BUF[0], \ | ^ ../../binutils-gdb/gdb/aarch64-tdep.c:4394:3: note: in expansion of macro ‘MEM_ALLOC’ 4394 | MEM_ALLOC (aarch64_insn_r->aarch64_mems, aarch64_insn_r->mem_rec_count, | ^~~~~~~~~ ../../binutils-gdb/gdb/aarch64-tdep.c:3721:12: note: destination object ‘aarch64_mem_r::len’ of size 8 3721 | uint64_t len; /* Record length. */ | ^~~ The simple fix is to reference the array, `MEMS' as the destination of the copy. Tested by rebuilding. # Please enter the commit message for your changes. Lines starting # with '#' will be kept; you may remove them yourself if you want to. # An empty message aborts the commit. # # Date: Tue Jan 25 08:28:32 2022 -0800 # # On branch master # Your branch is ahead of 'origin/master' by 1 commit. # (use "git push" to publish your local commits) # # Changes to be committed: # modified: aarch64-tdep.c # --- gdb/aarch64-tdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c index 63d626f90ac..b3efb3ebaff 100644 --- a/gdb/aarch64-tdep.c +++ b/gdb/aarch64-tdep.c @@ -3708,7 +3708,7 @@ When on, AArch64 specific debugging is enabled."), if (mem_len) \ { \ MEMS = XNEWVEC (struct aarch64_mem_r, mem_len); \ - memcpy(&MEMS->len, &RECORD_BUF[0], \ + memcpy(MEMS, &RECORD_BUF[0], \ sizeof(struct aarch64_mem_r) * LENGTH); \ } \ } \ -- 2.30.2