[lld] r363456 - [COFF] Handle .eh_frame$symbol as associative comdat for MinGW

[Martin Storsjo via llvm-commits]

Author: mstorsjo
Date: Fri Jun 14 14:02:04 2019
New Revision: 363456

URL: http://llvm.org/viewvc/llvm-project?rev=363456&view=rev
Log:
[COFF] Handle .eh_frame$symbol as associative comdat for MinGW

This matches how it is done for .xdata and .pdata already.

On i386, the symbol name in the section name suffix does not contain
the extra underscore prefix.

This is one part of a fix for PR42217.

Differential Revision: https://reviews.llvm.org/D63350

Added:
    lld/trunk/test/COFF/associative-comdat-mingw-i386.s
Modified:
    lld/trunk/COFF/InputFiles.cpp

Modified: lld/trunk/COFF/InputFiles.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/InputFiles.cpp?rev=363456&r1=363455&r2=363456&view=diff
==============================================================================
--- lld/trunk/COFF/InputFiles.cpp (original)
+++ lld/trunk/COFF/InputFiles.cpp Fri Jun 14 14:02:04 2019
@@ -288,6 +288,8 @@ void ObjFile::recordPrevailingSymbolForM
   if (SC && SC->getOutputCharacteristics() & IMAGE_SCN_MEM_EXECUTE) {
     StringRef Name;
     COFFObj->getSymbolName(Sym, Name);
+    if (getMachineType() == I386)
+      Name.consume_front("_");
     PrevailingSectionMap[Name] = SectionNumber;
   }
 }
@@ -297,9 +299,10 @@ void ObjFile::maybeAssociateSEHForMingw(
     const DenseMap<StringRef, uint32_t> &PrevailingSectionMap) {
   StringRef Name;
   COFFObj->getSymbolName(Sym, Name);
-  if (Name.consume_front(".pdata$") || Name.consume_front(".xdata$")) {
-    // For MinGW, treat .[px]data$<func> as implicitly associative to
-    // the symbol <func>.
+  if (Name.consume_front(".pdata$") || Name.consume_front(".xdata$") ||
+      Name.consume_front(".eh_frame$")) {
+    // For MinGW, treat .[px]data$<func> and .eh_frame$<func> as implicitly
+    // associative to the symbol <func>.
     auto ParentSym = PrevailingSectionMap.find(Name);
     if (ParentSym != PrevailingSectionMap.end())
       readAssociativeDefinition(Sym, Def, ParentSym->second);

Added: lld/trunk/test/COFF/associative-comdat-mingw-i386.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/associative-comdat-mingw-i386.s?rev=363456&view=auto
==============================================================================
--- lld/trunk/test/COFF/associative-comdat-mingw-i386.s (added)
+++ lld/trunk/test/COFF/associative-comdat-mingw-i386.s Fri Jun 14 14:02:04 2019
@@ -0,0 +1,37 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -triple=i686-windows-gnu %s -filetype=obj -o %t.obj
+
+# RUN: lld-link -lldmingw -entry:main %t.obj -out:%t.exe
+# RUN: llvm-objdump -s %t.exe | FileCheck %s
+
+# Check that the .eh_frame comdat was included, even if it had no symbols,
+# due to associativity with the symbol _foo.
+
+# CHECK: Contents of section .eh_fram:
+# CHECK:  403000 42
+
+        .text
+        .def            _main;
+        .scl            2;
+        .type           32;
+        .endef
+        .globl          _main
+        .p2align        4, 0x90
+_main:
+        call            _foo
+        ret
+
+        .section        .eh_frame$foo,"dr"
+        .linkonce       discard
+        .byte           0x42
+
+        .def            _foo;
+        .scl            2;
+        .type           32;
+        .endef
+        .section        .text$foo,"xr",discard,foo
+        .globl          _foo
+        .p2align        4
+_foo:
+        ret