Skip to content

Commit

Permalink
[Autolink Extract] Keep a set of linker flags instead of vector
Browse files Browse the repository at this point in the history 
Otherwise we can duplicate linker flags across input binaries, which can result in very large linkerr invocation commands.

Resolves swiftlang#58380
  • Loading branch information
@artemcm
artemcm committed May 20, 2022
1 parent 415c5c1 commit 10a187d
Show file tree
Hide file tree
Showing 2 changed files with 35 additions and 9 deletions.
36 changes: 28 additions & 8 deletions lib/DriverTool/autolink_extract_main.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@

#include <string>
#include <vector>
#include <unordered_set>

#include "swift/AST/DiagnosticsFrontend.h"
#include "swift/Frontend/Frontend.h"
Expand Down Expand Up @@ -112,6 +113,7 @@ class AutolinkExtractInvocation {
/// Return 'true' if there was an error, and 'false' otherwise.
static bool
extractLinkerFlagsFromObjectFile(const llvm::object::ObjectFile *ObjectFile,
std::unordered_set<std::string> &SeenLinkerLibraryFlags,
std::vector<std::string> &LinkerFlags,
CompilerInstance &Instance) {
// Search for the section we hold autolink entries in
Expand Down Expand Up @@ -140,8 +142,15 @@ extractLinkerFlagsFromObjectFile(const llvm::object::ObjectFile *ObjectFile,
llvm::SmallVector<llvm::StringRef, 4> SplitFlags;
SectionData->split(SplitFlags, llvm::StringRef("\0", 1), -1,
/*KeepEmpty=*/false);
for (const auto &Flag : SplitFlags)
LinkerFlags.push_back(Flag.str());
for (const auto &Flag : SplitFlags) {
// If this is a library '-lxxx' flag, only add it if we have not seen it before
if (Flag.str().rfind("-l", 0) == 0) {
auto SeenFlagsInsertResult = SeenLinkerLibraryFlags.insert(Flag.str());
if (SeenFlagsInsertResult.second == true)
LinkerFlags.push_back(Flag.str());
} else
LinkerFlags.push_back(Flag.str());
}
}
}
return false;
Expand All @@ -152,6 +161,7 @@ extractLinkerFlagsFromObjectFile(const llvm::object::ObjectFile *ObjectFile,
/// 'true' if there was an error, and 'false' otherwise.
static bool
extractLinkerFlagsFromObjectFile(const llvm::object::WasmObjectFile *ObjectFile,
std::unordered_set<std::string> &SeenLinkerLibraryFlags,
std::vector<std::string> &LinkerFlags,
CompilerInstance &Instance) {
// Search for the data segment we hold autolink entries in
Expand All @@ -164,8 +174,15 @@ extractLinkerFlagsFromObjectFile(const llvm::object::WasmObjectFile *ObjectFile,
llvm::SmallVector<llvm::StringRef, 4> SplitFlags;
SegmentData.split(SplitFlags, llvm::StringRef("\0", 1), -1,
/*KeepEmpty=*/false);
for (const auto &Flag : SplitFlags)
LinkerFlags.push_back(Flag.str());
for (const auto &Flag : SplitFlags) {
// If this is a library '-lxxx' flag, only add it if we have not seen it before
if (Flag.str().rfind("-l", 0) == 0) {
auto SeenFlagsInsertResult = SeenLinkerLibraryFlags.insert(Flag.str());
if (SeenFlagsInsertResult.second == true)
LinkerFlags.push_back(Flag.str());
} else
LinkerFlags.push_back(Flag.str());
}
}
}
return false;
Expand All @@ -178,12 +195,13 @@ extractLinkerFlagsFromObjectFile(const llvm::object::WasmObjectFile *ObjectFile,
static bool extractLinkerFlags(const llvm::object::Binary *Bin,
CompilerInstance &Instance,
StringRef BinaryFileName,
std::unordered_set<std::string> &SeenLinkerLibraryFlags,
std::vector<std::string> &LinkerFlags) {
if (auto *ObjectFile = llvm::dyn_cast<llvm::object::ELFObjectFileBase>(Bin)) {
return extractLinkerFlagsFromObjectFile(ObjectFile, LinkerFlags, Instance);
return extractLinkerFlagsFromObjectFile(ObjectFile, SeenLinkerLibraryFlags, LinkerFlags, Instance);
} else if (auto *ObjectFile =
llvm::dyn_cast<llvm::object::WasmObjectFile>(Bin)) {
return extractLinkerFlagsFromObjectFile(ObjectFile, LinkerFlags, Instance);
return extractLinkerFlagsFromObjectFile(ObjectFile, SeenLinkerLibraryFlags, LinkerFlags, Instance);
} else if (auto *Archive = llvm::dyn_cast<llvm::object::Archive>(Bin)) {
llvm::Error Error = llvm::Error::success();
for (const auto &Child : Archive->children(Error)) {
Expand All @@ -197,7 +215,7 @@ static bool extractLinkerFlags(const llvm::object::Binary *Bin,
return true;
}
if (extractLinkerFlags(ChildBinary->get(), Instance, BinaryFileName,
LinkerFlags)) {
SeenLinkerLibraryFlags, LinkerFlags)) {
return true;
}
}
Expand Down Expand Up @@ -228,6 +246,8 @@ int autolink_extract_main(ArrayRef<const char *> Args, const char *Argv0,
}

std::vector<std::string> LinkerFlags;
// Flags of the form '-lxxx' seen so far
std::unordered_set<std::string> SeenLinkerLibraryFlags;

// Extract the linker flags from the objects.
for (const auto &BinaryFileName : Invocation.getInputFilenames()) {
Expand All @@ -245,7 +265,7 @@ int autolink_extract_main(ArrayRef<const char *> Args, const char *Argv0,
}

if (extractLinkerFlags(BinaryOwner->getBinary(), Instance, BinaryFileName,
LinkerFlags)) {
SeenLinkerLibraryFlags, LinkerFlags)) {
return 1;
}
}
Expand Down
8 changes: 7 additions & 1 deletion test/AutolinkExtract/import.swift
View file
Original file line number Diff line number Diff line change
@@ -1,10 +1,16 @@
// RUN: %empty-directory(%t)
// RUN: %target-swiftc_driver -emit-module -emit-module-path %t/empty.swiftmodule -module-name empty -module-link-name empty %S/empty.swift
// RUN: %target-swiftc_driver -c %s -I %t -o %t/import_experimental.o
// RUN: %target-swift-autolink-extract %t/import_experimental.o -o - | %FileCheck --check-prefix CHECK-%target-object-format %s
// RUN: %target-swiftc_driver -c %s -I %t -o %t/import_experimental_again.o
// RUN: %target-swift-autolink-extract %t/import_experimental.o %t/import_experimental_again.o -o - | %FileCheck --check-prefix CHECK-%target-object-format %s

// RUN: %target-swift-autolink-extract %t/import_experimental.o %t/import_experimental_again.o -o - | %FileCheck --check-prefix UNIQUE %s

// REQUIRES: autolink-extract

// UNIQUE-COUNT-1: -lempty
// UNIQUE-COUNT-1: -lswiftCore

// CHECK-elf-DAG: -lswiftCore
// CHECK-elf-DAG: -lempty

Expand Down

0 comments on commit 10a187d

Please sign in to comment.