[PATCH] D43468: [ELF] - Support "INSERT AFTER" statement.

[Rafael Ávila de Espíndola via Phabricator via llvm-commits]

rafael added a comment.

LGTM

George Rimar via Phabricator via llvm-commits
<llvm-commits at lists.llvm.org> writes:

> grimar updated this revision to Diff 136968.
>  grimar added a comment.
> 
> - Rebased.
> - Implemented test case as a script.
> - Adjusted code slightly.
> 
> https://reviews.llvm.org/D43468
> 
> Files:
> 
>   ELF/Driver.cpp
>   ELF/LinkerScript.cpp
>   ELF/LinkerScript.h
>   ELF/ScriptParser.cpp
>   test/ELF/linkerscript/Inputs/insert-after.s
>   test/ELF/linkerscript/Inputs/insert-after.script
>   test/ELF/linkerscript/insert-after.test
> 
> Index: test/ELF/linkerscript/insert-after.test
>  ===================================================================
> 
>   - test/ELF/linkerscript/insert-after.test +++ test/ELF/linkerscript/insert-after.test @@ -0,0 +1,29 @@ +# REQUIRES: x86 +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/insert-after.s -o %t1.o + +## Main linker script contains .text and .data sections. Here +## we check that can use INSERT AFTER to insert sections .foo.data +## and .foo.text at the right places. + +SECTIONS { +  .foo.data : { *(.foo.data) } +} INSERT AFTER .data; + +SECTIONS { +  .foo.text : { *(.foo.text) } +} INSERT AFTER .text; + +# RUN: ld.lld %t1.o -o %t1 --script %p/Inputs/insert-after.script --script %s +# RUN: llvm-objdump -section-headers %t1 | FileCheck %s +# CHECK:      Sections: +# CHECK-NEXT: Idx Name          Size      Address          Type +# CHECK-NEXT:   0               00000000 0000000000000000 +# CHECK-NEXT:   1 .text         00000008 0000000000000000 TEXT DATA +# CHECK-NEXT:   2 .foo.text     00000008 0000000000000008 TEXT DATA +# CHECK-NEXT:   3 .data         00000008 0000000000000010 DATA +# CHECK-NEXT:   4 .foo.data     00000008 0000000000000018 DATA + +# RUN: not ld.lld %t1.o -o %t1 --script %s 2>&1 \ +# RUN:   | FileCheck %s --check-prefix=ERR +# ERR-DAG: error: unable to INSERT AFTER .text: section not defined +# ERR-DAG: error: unable to INSERT AFTER .data: section not defined Index: test/ELF/linkerscript/Inputs/insert-after.script ===================================================================
>   - test/ELF/linkerscript/Inputs/insert-after.script +++ test/ELF/linkerscript/Inputs/insert-after.script @@ -0,0 +1,4 @@ +SECTIONS { +  .text  : { *(.text.*) } +  .data  : { *(.data.*) } +} Index: test/ELF/linkerscript/Inputs/insert-after.s ===================================================================
>   - test/ELF/linkerscript/Inputs/insert-after.s +++ test/ELF/linkerscript/Inputs/insert-after.s @@ -0,0 +1,11 @@ +.section .foo.text,"ax" +.quad 0 + +.section .foo.data,"aw" +.quad 0 + +.section .text.1,"ax" +.quad 0 + +.section .data.1,"aw" +.quad 0 Index: ELF/ScriptParser.cpp ===================================================================
>   - ELF/ScriptParser.cpp +++ ELF/ScriptParser.cpp @@ -436,6 +436,7 @@ Config->SingleRoRx = true;
> 
>     expect("{"); +  std::vector<BaseCommand *> V; while (!errorCount() && !consume("}")) { StringRef Tok = next(); BaseCommand *Cmd = readProvideOrAssignment(Tok); @@ -445,8 +446,18 @@ else Cmd = readOutputSectionDescription(Tok); }
> - Script->SectionCommands.push_back(Cmd); +    V.push_back(Cmd); } + +  if (!atEOF() && consume("INSERT")) { +    consume("AFTER"); +    std::vector<BaseCommand *> &Dest = Script->PendingInserts[next()]; +    Dest.insert(Dest.end(), V.begin(), V.end()); +    return; +  } + +  Script->SectionCommands.insert(Script->SectionCommands.end(), V.begin(), +                                 V.end()); }
> 
>   static int precedence(StringRef Op) { Index: ELF/LinkerScript.h ===================================================================
>   - ELF/LinkerScript.h +++ ELF/LinkerScript.h @@ -267,6 +267,9 @@ void processSectionCommands(); void declareSymbols();
> 
>     +  // Used to handle INSERT AFTER statements. +  void processInsertCommands(); + // SECTIONS command list. std::vector<BaseCommand *> SectionCommands;
> 
>     @@ -285,6 +288,10 @@
> 
>     // A list of symbols referenced by the script. std::vector<llvm::StringRef> ReferencedSymbols; + +  // Used to implement INSERT AFTER. Contains commands that needs +  // to be inserted into SECTIONS commands list. +  llvm::DenseMap<StringRef, std::vector<BaseCommand *>> PendingInserts; };
> 
>     extern LinkerScript *Script; Index: ELF/LinkerScript.cpp ===================================================================
>   - ELF/LinkerScript.cpp +++ ELF/LinkerScript.cpp @@ -203,6 +203,25 @@ Cmd->Provide = false; }
> 
>     +// This method used to handle INSERT AFTER statement. Here we rebuild +// list of script commands to mix section inserted into. +void LinkerScript::processInsertCommands() { +  std::vector<BaseCommand *> V; +  for (BaseCommand *Base : SectionCommands) { +    V.push_back(Base); +    if (auto *Cmd = dyn_cast<OutputSection>(Base)) { +      std::vector<BaseCommand *> &InsertV = PendingInserts[Cmd->Name]; +      V.insert(V.end(), InsertV.begin(), InsertV.end()); +      InsertV.clear(); +    } +  } +  for (std::pair<StringRef, std::vector<BaseCommand *>> &P : PendingInserts) +    if (!P.second.empty()) +      error("unable to INSERT AFTER " + P.first + ": section not defined"); + +  SectionCommands.swap(V); +} + // Symbols defined in script should not be inlined by LTO. At the same time // we don't know their final values until late stages of link. Here we scan // over symbol assignment commands and create placeholder symbols if needed. Index: ELF/Driver.cpp ===================================================================
>   - ELF/Driver.cpp +++ ELF/Driver.cpp @@ -1081,6 +1081,10 @@ if (errorCount()) return;
> 
>     +  // Now when we read all script files, we want to finalize order of linker +  // script commands, which can be not yet final because of INSERT commands. +  Script->processInsertCommands(); + // We want to declare linker script's symbols early, // so that we can version them. // They also might be exported if referenced by DSOs. _______________________________________________ llvm-commits mailing list llvm-commits at lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits


https://reviews.llvm.org/D43468