[ELF] Linkerscript: fix KEEP

[evgeny777]

Summary

Our implementation of KEEP doesn't check file pattern. This patch fixes it.

[ruiu]

LGTM

ELF/LinkerScript.h

struct ScriptConfiguration {
   std::vector<PhdrsCommand> PhdrsCommands;
 
   bool HasSections = false;
 
   llvm::BumpPtrAllocator Alloc;
 
   // List of section patterns specified with KEEP commands. They will
   // be kept even if they are unused and --gc-sections is specified.
-  std::vector<llvm::Regex *> KeptSections;
+  std::vector<InputSectionDescription *> KeptSections;
 };
 
 extern ScriptConfiguration *ScriptConfig;
 
 // This is a runner of the linker script.
 template <class ELFT> class LinkerScript final : public LinkerScriptBase {
   typedef typename ELFT::uint uintX_t;
 

ELF/LinkerScript.cpp

template <class ELFT> static bool isDiscarded(InputSectionBase<ELFT> *S) {
   return !S || !S->Live;
 }
 
 template <class ELFT> LinkerScript<ELFT>::LinkerScript() {}
 template <class ELFT> LinkerScript<ELFT>::~LinkerScript() {}
 
 template <class ELFT>
 bool LinkerScript<ELFT>::shouldKeep(InputSectionBase<ELFT> *S) {
-  for (Regex *Re : Opt.KeptSections)
-    if (Re->match(S->Name))
+  for (InputSectionDescription *ID : Opt.KeptSections) {
+    StringRef Filename = S->getFile()->getName();
+    if (!ID->FileRe.match(sys::path::filename(Filename)))
+      continue;
+  
+    for (SectionPattern &P : ID->SectionPatterns) 
+      if (P.SectionRe.match(S->Name))
         return true;
+  }
   return false;
 }
 
 static bool comparePriority(InputSectionData *A, InputSectionData *B) {
   return getPriority(A->Name) < getPriority(B->Name);
 }
 
 static bool compareName(InputSectionData *A, InputSectionData *B) {

 ScriptParser::readInputSectionDescription(StringRef Tok) {
   // Input section wildcard can be surrounded by KEEP.
   // https://sourceware.org/binutils/docs/ld/Input-Section-Keep.html#Input-Section-Keep
   if (Tok == "KEEP") {
     expect("(");
     StringRef FilePattern = next();
     InputSectionDescription *Cmd = readInputSectionRules(FilePattern);
     expect(")");
-    for (SectionPattern &Pat : Cmd->SectionPatterns)
-      Opt.KeptSections.push_back(&Pat.SectionRe);
+    Opt.KeptSections.push_back(Cmd);
     return Cmd;
   }
   return readInputSectionRules(Tok);
 }
 
 void ScriptParser::readSort() {
   expect("(");
   expect("CONSTRUCTORS");

test/ELF/linkerscript/Inputs/keep.s

+.section .keep, "a"
+ .long 0x41414141

test/ELF/linkerscript/sections-keep.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/keep.s -o %t2.o
 
 ## First check that section "keep" is garbage collected without using KEEP
 # RUN: echo "SECTIONS { \
 # RUN:  .text : { *(.text) } \
 # RUN:  .keep : { *(.keep) } \
 # RUN:  .temp : { *(.temp) }}" > %t.script
 # RUN: ld.lld --gc-sections -o %t1 --script %t.script %t
 # RUN: llvm-objdump -section-headers %t1 | \

 # MIXED2-NEXT:   0               00000000
 # MIXED2-NEXT:   1 .nokeep       00000004 00000000000000e8 DATA
 # MIXED2-NEXT:   2 .text         00000007 00000000000000ec TEXT DATA
 # MIXED2-NEXT:   3 .temp         00000004 00000000000000f3 DATA
 # MIXED2-NEXT:   4 .symtab       00000060 0000000000000000
 # MIXED2-NEXT:   5 .shstrtab     0000002f 0000000000000000
 # MIXED2-NEXT:   6 .strtab       00000012 0000000000000000
 
+# Check file pattern for kept sections.
+# RUN: echo "SECTIONS { \
+# RUN:  . = SIZEOF_HEADERS; \
+# RUN:  .keep : { KEEP(*2.o(.keep)) } \
+# RUN:  }" > %t.script
+# RUN: ld.lld --gc-sections -o %t1 --script %t.script %t2.o %t
+# RUN: llvm-objdump -s %t1 | FileCheck -check-prefix=FILEMATCH %s
+# FILEMATCH:        Contents of section .keep:
+# FILEMATCH-NEXT:   00e8 41414141  AAAA
+
 .global _start
 _start:
  mov temp, %eax
 
 .section .keep, "a"
 keep:
  .long 1
 
 .section .temp, "a"
 temp:
  .long 2