[PATCH] D39544: [ELF] - Linkerscript: fixed non-determinism when handling MEMORY.

[George Rimar via Phabricator via llvm-commits]

grimar created this revision.
Herald added a subscriber: emaste.

When `findMemoryRegion` do search to find a region for output section it
iterates over `MemoryRegions` which is DenseMap and so does not
guarantee iteration in insertion order. As a result selected region depends
on its name and not on its definition position
Testcase shows the issue, patch fixes it. Behavior after applying the patch
seems consistent with bfd.


https://reviews.llvm.org/D39544

Files:
  ELF/LinkerScript.h
  test/ELF/linkerscript/memory3.s


Index: test/ELF/linkerscript/memory3.s
===================================================================
--- test/ELF/linkerscript/memory3.s
+++ test/ELF/linkerscript/memory3.s
@@ -0,0 +1,17 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: echo "MEMORY { ram2 (ax) : ORIGIN = 0x1000, LENGTH = 1K   \
+# RUN:                ram1 (ax) : ORIGIN = 0x4000, LENGTH = 1K } \
+# RUN: SECTIONS {}" > %t.script
+# RUN: ld.lld -o %t2 --script %t.script %t
+# RUN: llvm-objdump -section-headers %t2 | FileCheck %s
+
+## Check we place .text into first defined memory region with appropriate flags.
+# CHECK: Sections:
+# CHECK: Idx Name  Size      Address
+# CHECK:   0       00000000 0000000000000000
+# CHECK:   1 .text 00000001 0000000000001000
+  
+.section .text.foo,"ax",%progbits
+foo:
+  nop
Index: ELF/LinkerScript.h
===================================================================
--- ELF/LinkerScript.h
+++ ELF/LinkerScript.h
@@ -277,7 +277,7 @@
   std::vector<InputSectionDescription *> KeptSections;
 
   // A map from memory region name to a memory region descriptor.
-  llvm::DenseMap<llvm::StringRef, MemoryRegion *> MemoryRegions;
+  llvm::MapVector<llvm::StringRef, MemoryRegion *> MemoryRegions;
 
   // A list of symbols referenced by the script.
   std::vector<llvm::StringRef> ReferencedSymbols;


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