From: Eugene Leviant <evgeny.leviant@gmail.com>
Date: Thu, 20 Oct 2016 09:39:09 +0000 (+0000)
Subject: Don't include PHDRs if linker script doesn't want them
X-Git-Tag: llvmorg-4.0.0-rc1~6707
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=db35fdf70f08d6f644ef2679b8e79af59e710f16;p=platform%2Fupstream%2Fllvm.git

Don't include PHDRs if linker script doesn't want them

This script below shouldn't include file and program headers
to PT_LOAD segment, because it doesn't have PHDRS and FILEHDR
attributes:

PHDRS { all PT_LOAD; }
SECTIONS { /* list of sections here */ }

Differential revision: https://reviews.llvm.org/D25774

llvm-svn: 284709
---

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index b1462e0..ba8bb4c 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -652,7 +652,16 @@ void LinkerScript<ELFT>::assignAddresses(std::vector<PhdrEntry<ELFT>> &Phdrs) {
       std::find_if(Phdrs.begin(), Phdrs.end(), [](const PhdrEntry<ELFT> &E) {
         return E.H.p_type == PT_LOAD;
       });
+
   if (HeaderSize <= MinVA && FirstPTLoad != Phdrs.end()) {
+    // If linker script specifies program headers and first PT_LOAD doesn't 
+    // have both PHDRS and FILEHDR attributes then do nothing
+    if (!Opt.PhdrsCommands.empty()) {
+      size_t SegNum = std::distance(Phdrs.begin(), FirstPTLoad);
+      if (!Opt.PhdrsCommands[SegNum].HasPhdrs ||
+          !Opt.PhdrsCommands[SegNum].HasFilehdr)
+        return;
+    }
     // ELF and Program headers need to be right before the first section in
     // memory. Set their addresses accordingly.
     MinVA = alignDown(MinVA - HeaderSize, Target->PageSize);
diff --git a/lld/test/ELF/linkerscript/phdrs.s b/lld/test/ELF/linkerscript/phdrs.s
index 67c1e35..87feea4 100644
--- a/lld/test/ELF/linkerscript/phdrs.s
+++ b/lld/test/ELF/linkerscript/phdrs.s
@@ -9,6 +9,17 @@
 # RUN: ld.lld -o %t1 --script %t.script %t
 # RUN: llvm-readobj -program-headers %t1 | FileCheck %s
 
+## Check that program headers are not written, unless we explicitly tell
+## lld to do this.
+# RUN: echo "PHDRS {all PT_LOAD;} \
+# RUN:       SECTIONS { \
+# RUN:           . = 0x10000200; \
+# RUN:           /DISCARD/ : {*(.text*)}  \
+# RUN:           .foo : {*(.foo.*)} :all \
+# RUN:       }" > %t.script
+# RUN: ld.lld -o %t1 --script %t.script %t
+# RUN: llvm-readobj -program-headers %t1 | FileCheck --check-prefix=NOPHDR %s
+
 ## Check the AT(expr)
 # RUN: echo "PHDRS {all PT_LOAD FILEHDR PHDRS AT(0x500 + 0x500) ;} \
 # RUN:       SECTIONS { \
@@ -42,6 +53,22 @@
 # CHECK-NEXT:      PF_X (0x1)
 # CHECK-NEXT:    ]
 
+# NOPHDR:     ProgramHeaders [
+# NOPHDR-NEXT:  ProgramHeader {
+# NOPHDR-NEXT:    Type: PT_LOAD (0x1)
+# NOPHDR-NEXT:    Offset: 0x200
+# NOPHDR-NEXT:    VirtualAddress: 0x10000200
+# NOPHDR-NEXT:    PhysicalAddress: 0x10000200
+# NOPHDR-NEXT:    FileSize: 8
+# NOPHDR-NEXT:    MemSize: 8
+# NOPHDR-NEXT:    Flags [ (0x6)
+# NOPHDR-NEXT:      PF_R (0x4)
+# NOPHDR-NEXT:      PF_W (0x2)
+# NOPHDR-NEXT:    ]
+# NOPHDR-NEXT:    Alignment: 4096
+# NOPHDR-NEXT:  }
+# NOPHDR-NEXT: ]
+
 # AT:       ProgramHeaders [
 # AT-NEXT:    ProgramHeader {
 # AT-NEXT:      Type: PT_LOAD (0x1)