Index: ELF/Writer.cpp =================================================================== --- ELF/Writer.cpp +++ ELF/Writer.cpp @@ -1855,11 +1855,6 @@ Sec->writeTo(Buf + Sec->Offset); } -static void fillTrap(uint8_t *I, uint8_t *End) { - for (; I + 4 < End; I += 4) - memcpy(I, &Target->TrapInstr, 4); -} - // Fill the last page of executable segments with trap instructions // instead of leaving them as zero. Even though it is not required by any // standard, it is in general a good thing to do for security reasons. @@ -1872,10 +1867,14 @@ // Fill the last page. uint8_t *Buf = Buffer->getBufferStart(); - for (PhdrEntry *P : Phdrs) - if (P->p_type == PT_LOAD && (P->p_flags & PF_X)) - fillTrap(Buf + alignDown(P->p_offset + P->p_filesz, Target->PageSize), - Buf + alignTo(P->p_offset + P->p_filesz, Target->PageSize)); + for (PhdrEntry *P : Phdrs) { + if (P->p_type != PT_LOAD || !(P->p_flags & PF_X)) + continue; + uint8_t *I = Buf + alignDown(P->p_offset + P->p_filesz, Target->PageSize); + uint8_t *End = Buf + alignTo(P->p_offset + P->p_filesz, Target->PageSize); + for (; I + 4 <= End; I += 4) + memcpy(I, &Target->TrapInstr, 4); + } // Round up the file size of the last segment to the page boundary iff it is // an executable segment to ensure that other other tools don't accidentally Index: test/ELF/build-id.s =================================================================== --- test/ELF/build-id.s +++ test/ELF/build-id.s @@ -48,15 +48,15 @@ # DEFAULT: Contents of section .note.test: # DEFAULT: Contents of section .note.gnu.build-id: # DEFAULT-NEXT: 04000000 08000000 03000000 474e5500 ............GNU. -# DEFAULT-NEXT: d618a375 bc6301ec +# DEFAULT-NEXT: b0148597 ba5eb7e9 # MD5: Contents of section .note.gnu.build-id: # MD5-NEXT: 04000000 10000000 03000000 474e5500 ............GNU. -# MD5-NEXT: 051084fe ce1f30ed e035b79e 11262808 +# MD5-NEXT: dce3bcaf 5219454c e89a1fc7 86ab17bd # SHA1: Contents of section .note.gnu.build-id: # SHA1-NEXT: 04000000 14000000 03000000 474e5500 ............GNU. -# SHA1-NEXT: c70b9aec 903fd291 8b677cd8 1e04f8b6 +# SHA1-NEXT: 2f716666 fe3668fe 370a02a1 579c3eb2 # UUID: Contents of section .note.gnu.build-id: # UUID-NEXT: 04000000 10000000 03000000 474e5500 ............GNU. Index: test/ELF/fill-trap.s =================================================================== --- test/ELF/fill-trap.s +++ test/ELF/fill-trap.s @@ -0,0 +1,25 @@ +# REQUIRES: x86 + +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t +# RUN: ld.lld %t -o %t2 +# RUN: llvm-readobj -program-headers %t2 | FileCheck %s +# RUN: hexdump -v -s 0x0001ff0 %t2 | FileCheck %s -check-prefix=FILL + +# CHECK: ProgramHeader { +# CHECK: Type: PT_LOAD +# CHECK: Offset: 0x1000 +# CHECK-NEXT: VirtualAddress: +# CHECK-NEXT: PhysicalAddress: +# CHECK-NEXT: FileSize: 4096 +# CHECK-NEXT: MemSize: +# CHECK-NEXT: Flags [ +# CHECK-NEXT: PF_R +# CHECK-NEXT: PF_X +# CHECK-NEXT: ] + +## Check that executable page is filled with traps at it's end. +# FILL: 0001ff0 cccc cccc cccc cccc cccc cccc cccc cccc + +.globl _start +_start: + nop