[ELF] - Linkerscript: fix VA value assigned to sections when using constraints.

Previously we searched output section by name to assign VA. That did not
work in the case when multiple output sections with different constraints were defined in script.
Testcase shows the possible issue scenario, patch fixes the issue.

Differential revision: https://reviews.llvm.org/D23451

llvm-svn: 278561

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 95b28e2..ca5ab37 100644 (file)
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -215,14 +215,20 @@ void LinkerScript<ELFT>::discard(OutputSectionCommand &Cmd) {
   }
 }
 
+static bool checkConstraint(uint64_t Flags, ConstraintKind Kind) {
+  bool RO = (Kind == ConstraintKind::ReadOnly);
+  bool RW = (Kind == ConstraintKind::ReadWrite);
+  bool Writable = Flags & SHF_WRITE;
+  return !((RO && Writable) || (RW && !Writable));
+}
+
 template <class ELFT>
 static bool matchConstraints(ArrayRef<InputSectionBase<ELFT> *> Sections,
                              ConstraintKind Kind) {
-  bool RO = (Kind == ConstraintKind::ReadOnly);
-  bool RW = (Kind == ConstraintKind::ReadWrite);
-  return !llvm::any_of(Sections, [=](InputSectionBase<ELFT> *Sec) {
-    bool Writable = Sec->getSectionHdr()->sh_flags & SHF_WRITE;
-    return (RO && Writable) || (RW && !Writable);
+  if (Kind == ConstraintKind::NoConstraint)
+    return true;
+  return llvm::all_of(Sections, [=](InputSectionBase<ELFT> *Sec) {
+    return checkConstraint(Sec->getSectionHdr()->sh_flags, Kind);
   });
 }
 
@@ -330,6 +336,19 @@ template <class ELFT> void assignOffsets(OutputSectionBase<ELFT> *Sec) {
   }
 }
 
+template <class ELFT>
+static OutputSectionBase<ELFT> *
+findSection(OutputSectionCommand &Cmd,
+            ArrayRef<OutputSectionBase<ELFT> *> Sections) {
+  for (OutputSectionBase<ELFT> *Sec : Sections) {
+    if (Sec->getName() != Cmd.Name)
+      continue;
+    if (checkConstraint(Sec->getFlags(), Cmd.Constraint))
+      return Sec;
+  }
+  return nullptr;
+}
+
 template <class ELFT> void LinkerScript<ELFT>::assignAddresses() {
   // Orphan sections are sections present in the input files which
   // are not explicitly placed into the output file by the linker script.
@@ -363,12 +382,9 @@ template <class ELFT> void LinkerScript<ELFT>::assignAddresses() {
     }
 
     auto *Cmd = cast<OutputSectionCommand>(Base.get());
-    auto I = llvm::find_if(*OutputSections, [&](OutputSectionBase<ELFT> *S) {
-      return S->getName() == Cmd->Name;
-    });
-    if (I == OutputSections->end())
+    OutputSectionBase<ELFT> *Sec = findSection<ELFT>(*Cmd, *OutputSections);
+    if (!Sec)
       continue;
-    OutputSectionBase<ELFT> *Sec = *I;
 
     if (Cmd->AddrExpr)
       Dot = Cmd->AddrExpr(Dot);

diff --git a/lld/test/ELF/linkerscript/linkerscript-multi-sections-constraint.s b/lld/test/ELF/linkerscript/linkerscript-multi-sections-constraint.s
index c9d0943..e131215 100644 (file)
--- a/lld/test/ELF/linkerscript/linkerscript-multi-sections-constraint.s
+++ b/lld/test/ELF/linkerscript/linkerscript-multi-sections-constraint.s
@@ -15,6 +15,21 @@
 # CHECK-NEXT:   4 .shstrtab     00000026 0000000000000000
 # CHECK-NEXT:   5 .strtab       00000008 0000000000000000
 
+# RUN: echo "SECTIONS { \
+# RUN:  . = 0x1000; .aaa : ONLY_IF_RW { *(.aaa.*) } \
+# RUN:  . = 0x2000; .aaa : ONLY_IF_RO { *(.aaa.*) } } " > %t2.script
+# RUN: ld.lld -o %t2 --script %t2.script %t
+# RUN: llvm-objdump -section-headers %t2 | FileCheck %s --check-prefix=REV
+
+# REV:      Sections:
+# REV-NEXT: Idx Name          Size      Address          Type
+# REV-NEXT:   0               00000000 0000000000000000
+# REV-NEXT:   1 .aaa          00000010 0000000000001000 DATA
+# REV-NEXT:   2 .text         00000001 0000000000002000 TEXT DATA
+# REV-NEXT:   3 .symtab       00000030 0000000000000000
+# REV-NEXT:   4 .shstrtab     00000026 0000000000000000
+# REV-NEXT:   5 .strtab       00000008 0000000000000000
+
 .global _start
 _start:
  nop