[lld] r326207 - Add support for SHF_ARM_PURECODE.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Tue Feb 27 08:55:25 2018
New Revision: 326207

URL: http://llvm.org/viewvc/llvm-project?rev=326207&view=rev
Log:
Add support for SHF_ARM_PURECODE.

Now we don't mark a PT_LOAD as readable if all its sections are
SHF_ARM_PURECODE.

Added:
    lld/trunk/test/ELF/arm-execute-only.s
Modified:
    lld/trunk/ELF/OutputSections.cpp

Modified: lld/trunk/ELF/OutputSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=326207&r1=326206&r2=326207&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.cpp (original)
+++ lld/trunk/ELF/OutputSections.cpp Tue Feb 27 08:55:25 2018
@@ -45,7 +45,9 @@ OutputSection *Out::FiniArray;
 std::vector<OutputSection *> elf::OutputSections;
 
 uint32_t OutputSection::getPhdrFlags() const {
-  uint32_t Ret = PF_R;
+  uint32_t Ret = 0;
+  if (Config->EMachine != EM_ARM || !(Flags & SHF_ARM_PURECODE))
+    Ret |= PF_R;
   if (Flags & SHF_WRITE)
     Ret |= PF_W;
   if (Flags & SHF_EXECINSTR)
@@ -110,10 +112,11 @@ static bool canMergeToProgbits(unsigned
 void OutputSection::addSection(InputSection *IS) {
   if (!Live) {
     // If IS is the first section to be added to this section,
-    // initialize Type and Entsize from IS.
+    // initialize Type, Entsize and flags from IS.
     Live = true;
     Type = IS->Type;
     Entsize = IS->Entsize;
+    Flags = IS->Flags;
   } else {
     // Otherwise, check if new type or flags are compatible with existing ones.
     if ((Flags & (SHF_ALLOC | SHF_TLS)) != (IS->Flags & (SHF_ALLOC | SHF_TLS)))
@@ -133,7 +136,12 @@ void OutputSection::addSection(InputSect
   }
 
   IS->Parent = this;
-  Flags |= IS->Flags;
+  uint64_t AndMask = Config->EMachine == EM_ARM ? SHF_ARM_PURECODE : 0;
+  uint64_t OrMask = ~AndMask;
+  uint64_t AndFlags = (Flags & IS->Flags) & AndMask;
+  uint64_t OrFlags = (Flags | IS->Flags) & OrMask;
+  Flags = AndFlags | OrFlags;
+
   Alignment = std::max(Alignment, IS->Alignment);
   IS->OutSecOff = Size++;
 

Added: lld/trunk/test/ELF/arm-execute-only.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/arm-execute-only.s?rev=326207&view=auto
==============================================================================
--- lld/trunk/test/ELF/arm-execute-only.s (added)
+++ lld/trunk/test/ELF/arm-execute-only.s Tue Feb 27 08:55:25 2018
@@ -0,0 +1,38 @@
+// RUN: llvm-mc -filetype=obj -triple=armv7-pc-linux %s -o %t.o
+// RUN: ld.lld %t.o -o %t.so -shared
+// RUN: llvm-readelf -l %t.so | FileCheck %s
+
+// RUN: ld.lld %t.o %t.o -o %t.so -shared
+// RUN: llvm-readelf -l %t.so | FileCheck %s
+
+// RUN: echo ".section .foo,\"ax\"; \
+// RUN:       bx lr" > %t.s
+// RUN: llvm-mc -filetype=obj -triple=armv7-pc-linux %t.s -o %t2.o
+// RUN: ld.lld %t.o %t2.o -o %t.so -shared
+// RUN: llvm-readelf -l %t.so | FileCheck --check-prefix=DIFF %s
+
+// CHECK-NOT:  LOAD
+// CHECK:      LOAD           0x000000 0x00000000 0x00000000 0x00169  0x00169  R   0x1000
+// CHECK:      LOAD           0x001000 0x00001000 0x00001000 0x{{.*}} 0x{{.*}} R E 0x1000
+// CHECK:      LOAD           0x002000 0x00002000 0x00002000 0x{{.*}} 0x{{.*}}   E 0x1000
+// CHECK:      LOAD           0x003000 0x00003000 0x00003000 0x00038  0x00038  RW  0x1000
+// CHECK-NOT:  LOAD
+
+// CHECK: 01     .dynsym .gnu.hash .hash .dynstr
+// CHECK: 02     .text
+// CHECK: 03     .foo
+// CHECK: 04     .dynamic
+
+// DIFF-NOT:  LOAD
+// DIFF:      LOAD           0x000000 0x00000000 0x00000000 0x00149 0x00149 R   0x1000
+// DIFF:      LOAD           0x001000 0x00001000 0x00001000 0x0000c 0x0000c R E 0x1000
+// DIFF:      LOAD           0x002000 0x00002000 0x00002000 0x00038 0x00038 RW  0x1000
+// DIFF-NOT:  LOAD
+
+// DIFF: 01     .dynsym .gnu.hash .hash .dynstr
+// DIFF: 02     .text .foo
+// DIFF: 03     .dynamic
+
+        bx lr
+        .section .foo,"axy"
+        bx lr