Add trap instructions for ARM and MIPS.

This patch fills holes in executable sections with 0xd4 (ARM) or
0xef (MIPS). These trap instructions were suggested by Theo de Raadt.

llvm-svn: 306322

4 files changed, 4 insertions, 6 deletions

diff --git a/lld/ELF/Arch/ARM.cpp b/lld/ELF/Arch/ARM.cpp
index a8a5ca15144..e4b06ade448 100644
--- a/lld/ELF/Arch/ARM.cpp
+++ b/lld/ELF/Arch/ARM.cpp
@@ -57,6 +57,7 @@ ARM::ARM() {
   GotPltEntrySize = 4;
   PltEntrySize = 16;
   PltHeaderSize = 20;
+  TrapInstr = 0xd4d4d4d4;
   // ARM uses Variant 1 TLS
   TcbSize = 8;
   NeedsThunks = true;
diff --git a/lld/ELF/Arch/Mips.cpp b/lld/ELF/Arch/Mips.cpp
index 422e5db8ce2..b8d796f5897 100644
--- a/lld/ELF/Arch/Mips.cpp
+++ b/lld/ELF/Arch/Mips.cpp
@@ -54,6 +54,7 @@ template <class ELFT> MIPS<ELFT>::MIPS() {
   CopyRel = R_MIPS_COPY;
   PltRel = R_MIPS_JUMP_SLOT;
   NeedsThunks = true;
+  TrapInstr = 0xefefefef;
 
   if (ELFT::Is64Bits) {
     RelativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32;
diff --git a/lld/ELF/Arch/X86.cpp b/lld/ELF/Arch/X86.cpp
index f605a8583ba..a1e9bcaf1b1 100644
--- a/lld/ELF/Arch/X86.cpp
+++ b/lld/ELF/Arch/X86.cpp
@@ -60,9 +60,7 @@ X86::X86() {
   PltEntrySize = 16;
   PltHeaderSize = 16;
   TlsGdRelaxSkip = 2;
-
-  // 0xCC is the "int3" (call debug exception handler) instruction.
-  TrapInstr = 0xcccccccc;
+  TrapInstr = 0xcccccccc; // 0xcc = INT3
 }
 
 RelExpr X86::getRelExpr(uint32_t Type, const SymbolBody &S,
diff --git a/lld/ELF/Arch/X86_64.cpp b/lld/ELF/Arch/X86_64.cpp
index 569b44da93d..10179f57ee9 100644
--- a/lld/ELF/Arch/X86_64.cpp
+++ b/lld/ELF/Arch/X86_64.cpp
@@ -65,13 +65,11 @@ template <class ELFT> X86_64<ELFT>::X86_64() {
   PltEntrySize = 16;
   PltHeaderSize = 16;
   TlsGdRelaxSkip = 2;
+  TrapInstr = 0xcccccccc; // 0xcc = INT3
 
   // Align to the large page size (known as a superpage or huge page).
   // FreeBSD automatically promotes large, superpage-aligned allocations.
   DefaultImageBase = 0x200000;
-
-  // 0xCC is the "int3" (call debug exception handler) instruction.
-  TrapInstr = 0xcccccccc;
 }
 
 template <class ELFT>