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[llvm-dwp] Add a new flag --exec-dwo-path-remapping-file=<filename>. #157587

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[llvm-dwp] Add a new flag --exec-dwo-path-remapping-file=<filename>. #157587

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129 changes: 129 additions & 0 deletions llvm/test/tools/llvm-dwp/X86/dwos_list_from_exec_remap.test
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@@ -0,0 +1,129 @@
// Test remapping old DWO paths in the executables and libraries to new paths.

RUN: rm -rf %t
RUN: mkdir %t
RUN: cd %t

RUN: cp %p/../Inputs/dwos_list_from_exec/main main
RUN: cp %p/../Inputs/dwos_list_from_exec/libd.so libd.so

// Test remapping full DWO paths (<DW_AT_comp_dir>/<DW_AT_dwo_name>) to absolute paths
RUN: touch remapping_path_to_absolute.txt
RUN: echo "./a.dwo %p/../Inputs/dwos_list_from_exec/a.dwo" >> remapping_path_to_absolute.txt
RUN: echo "./b.dwo %p/../Inputs/dwos_list_from_exec/b.dwo" >> remapping_path_to_absolute.txt
RUN: echo "./d.dwo %p/../Inputs/dwos_list_from_exec/d.dwo" >> remapping_path_to_absolute.txt
RUN: llvm-dwp %p/../Inputs/dwos_list_from_exec/c.dwo %p/../Inputs/dwos_list_from_exec/e.dwo \
RUN: -e main -e libd.so --exec-dwo-path-remapping-file=remapping_path_to_absolute.txt -o - | llvm-dwarfdump -v - | FileCheck %s

// Test remapping full DWO paths (<DW_AT_comp_dir>/<DW_AT_dwo_name>) to relative paths
RUN: mkdir foo && cp %p/../Inputs/dwos_list_from_exec/a.dwo foo/a.dwo
RUN: mkdir bar && cp %p/../Inputs/dwos_list_from_exec/b.dwo bar/b.dwo
RUN: mkdir qux && cp %p/../Inputs/dwos_list_from_exec/d.dwo qux/d.dwo
RUN: touch remapping_path_to_relative.txt
RUN: echo "./a.dwo foo/a.dwo" >> remapping_path_to_relative.txt
RUN: echo "./b.dwo bar/b.dwo" >> remapping_path_to_relative.txt
RUN: echo "./d.dwo qux/d.dwo" >> remapping_path_to_relative.txt
RUN: llvm-dwp %p/../Inputs/dwos_list_from_exec/c.dwo %p/../Inputs/dwos_list_from_exec/e.dwo \
RUN: -e main -e libd.so --exec-dwo-path-remapping-file=remapping_path_to_relative.txt -o - | llvm-dwarfdump -v - | FileCheck %s

// Test remapping DWO name (<DW_AT_dwo_name>) to relative paths
RUN: touch remapping_name_to_relative.txt
RUN: echo "a.dwo foo/a.dwo" >> remapping_name_to_relative.txt
RUN: echo "b.dwo bar/b.dwo" >> remapping_name_to_relative.txt
RUN: echo "d.dwo qux/d.dwo" >> remapping_name_to_relative.txt
RUN: llvm-dwp %p/../Inputs/dwos_list_from_exec/c.dwo %p/../Inputs/dwos_list_from_exec/e.dwo \
RUN: -e main -e libd.so --exec-dwo-path-remapping-file=remapping_name_to_relative.txt -o - | llvm-dwarfdump -v - | FileCheck %s

// Test remapping with multiple files
RUN: touch remapping_main.txt
RUN: echo "./a.dwo %p/../Inputs/dwos_list_from_exec/a.dwo" >> remapping_main.txt
RUN: echo "./b.dwo %p/../Inputs/dwos_list_from_exec/b.dwo" >> remapping_main.txt
RUN: echo "./d.dwo %p/../Inputs/dwos_list_from_exec/d.dwo" > remapping_libd.txt
RUN: llvm-dwp %p/../Inputs/dwos_list_from_exec/c.dwo %p/../Inputs/dwos_list_from_exec/e.dwo \
RUN: -e main -e libd.so \
RUN: --exec-dwo-path-remapping-file=remapping_main.txt \
RUN: --exec-dwo-path-remapping-file=remapping_libd.txt \
RUN: -o - | llvm-dwarfdump -v - | FileCheck %s

Build commands for the test binaries:

clang++ -Xclang -fdebug-compilation-dir -Xclang "./" -g -O0 -gsplit-dwarf a.cpp b.cpp -o main
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Can you specify dwarf version explicitly, in case default changes in the future.
Kind of surprised it defaults to 4. I thought 5 was the default now.

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@mpark mpark Sep 10, 2025 •
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I'm basically willing to do whatever here, but I'm not sure just adding -gdwarf-5 here makes sense. This test is largely copied from the existing dwos_list_from_exec_simple.test, which has these binaries checked into the repo under Inputs/dwos_list_from_exec. The binaries were definitely built to DWARF-4 spec. I could specify -gdwarf-5 in both and update the checked in binaries or, alternatively I could specify -gdwarf-4 in these tests to pin the version. Do you have a preferred approach?

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Oh I missed this operates on binary level. I thought we converted all tests to be text version. Never mind.

clang++ -g -O0 -gsplit-dwarf -c c.cpp -o c.o
clang++ -Xclang -fdebug-compilation-dir -Xclang "./" -g -O0 -gsplit-dwarf -fPIC -shared d.cpp -o libd.so
clang++ -g -O0 -gsplit-dwarf -c e.cpp -o e.o

sources:
a.cpp:
void a() {}

b.cpp:
void b() {}
int main() {
return 0;
}

c.cpp:
void c() {}

d.cpp:
void d() {}

e.cpp:
void e() {}

CHECK-LABEL: .debug_abbrev.dwo contents:

CHECK-LABEL: Abbrev table for offset:
CHECK: DW_TAG_compile_unit
CHECK: DW_TAG_subprogram

CHECK-LABEL: Abbrev table for offset:
CHECK: DW_TAG_compile_unit
CHECK: DW_TAG_subprogram

CHECK-LABEL: Abbrev table for offset:
CHECK: DW_TAG_compile_unit
CHECK: DW_TAG_subprogram

CHECK-LABEL: Abbrev table for offset:
CHECK: DW_TAG_compile_unit
CHECK: DW_TAG_subprogram

CHECK-LABEL: Abbrev table for offset:
CHECK: DW_TAG_compile_unit
CHECK: DW_TAG_subprogram

CHECK: .debug_info.dwo contents:
CHECK: [[AOFF:0x[0-9a-f]*]]:

CHECK-LABEL: Compile Unit: length = {{.*}}, version = 0x0004
CHECK: DW_TAG_compile_unit
CHECK: DW_AT_name {{.*}} "c.cpp"
CHECK: DW_TAG_subprogram
CHECK: DW_AT_name {{.*}} "c"

CHECK-LABEL: Compile Unit: length = {{.*}}, version = 0x0004
CHECK: DW_TAG_compile_unit
CHECK: DW_AT_name {{.*}} "e.cpp"
CHECK: DW_TAG_subprogram
CHECK: DW_AT_name {{.*}} "e"

CHECK-LABEL: Compile Unit: length = {{.*}}, version = 0x0004
CHECK: DW_TAG_compile_unit
CHECK: DW_AT_name {{.*}} "a.cpp"
CHECK: DW_TAG_subprogram
CHECK: DW_AT_name {{.*}} "a"

CHECK-LABEL: Compile Unit: length = {{.*}}, version = 0x0004
CHECK: DW_TAG_compile_unit
CHECK: DW_AT_name {{.*}} "b.cpp"
CHECK: DW_TAG_subprogram
CHECK: DW_AT_name {{.*}} "b"
CHECK: DW_TAG_subprogram
CHECK: DW_AT_name {{.*}} "main"

CHECK-LABEL: Compile Unit: length = {{.*}}, version = 0x0004
CHECK: DW_TAG_compile_unit
CHECK: DW_AT_name {{.*}} "d.cpp"
CHECK: DW_TAG_subprogram
CHECK: DW_AT_name {{.*}} "d"
2 changes: 2 additions & 0 deletions llvm/tools/llvm-dwp/Opts.td
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Expand Up @@ -16,3 +16,5 @@ def continueOnCuIndexOverflow_EQ : Joined<["-", "--"], "continue-on-cu-index-ove
"\t\ttruncated but valid DWP file, discarding any DWO files that would not fit within \n"
"\t\tthe 32 bit/4GB limits of the format.">,
Values<"continue,soft-stop">;
def execDwoPathRemappingFile : Joined<["--"], "exec-dwo-path-remapping-file=">, MetaVarName<"<filename>">,
HelpText<"Use the old and new paths described in <filename> to map old dwo paths in executables/libraries to the new paths.">;
47 changes: 45 additions & 2 deletions llvm/tools/llvm-dwp/llvm-dwp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
// package files).
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringMap.h"
#include "llvm/DWP/DWP.h"
#include "llvm/DWP/DWPError.h"
#include "llvm/DWP/DWPStringPool.h"
Expand Down Expand Up @@ -75,7 +76,8 @@ static std::string OutputFilename;
static std::string ContinueOption;

static Expected<SmallVector<std::string, 16>>
getDWOFilenames(StringRef ExecFilename) {
getDWOFilenames(StringRef ExecFilename,
const StringMap<StringRef> &DWOPathMap) {
auto ErrOrObj = object::ObjectFile::createObjectFile(ExecFilename);
if (!ErrOrObj)
return ErrOrObj.takeError();
Expand All @@ -95,11 +97,17 @@ getDWOFilenames(StringRef ExecFilename) {
if (!DWOCompDir.empty()) {
SmallString<16> DWOPath(DWOName);
sys::fs::make_absolute(DWOCompDir, DWOPath);
if (auto I = DWOPathMap.find(DWOPath); I != DWOPathMap.end())
DWOPath = I->getValue();
if (auto I = DWOPathMap.find(DWOName); I != DWOPathMap.end())
DWOName = I->getValue();
if (!sys::fs::exists(DWOPath) && sys::fs::exists(DWOName))
DWOPaths.push_back(std::move(DWOName));
else
DWOPaths.emplace_back(DWOPath.data(), DWOPath.size());
} else {
if (auto I = DWOPathMap.find(DWOName); I != DWOPathMap.end())
DWOName = I->getValue();
DWOPaths.push_back(std::move(DWOName));
}
}
Expand All @@ -120,6 +128,33 @@ static Expected<Triple> readTargetTriple(StringRef FileName) {
return ErrOrObj->getBinary()->makeTriple();
}

static Error addPathsToRemapFromFile(StringMap<StringRef> &DWOPathMap,
BumpPtrAllocator &Alloc,
StringRef Filename) {
StringSaver Saver(Alloc);
SmallVector<StringRef, 16> Lines;
auto BufOrErr = MemoryBuffer::getFile(Filename);
if (!BufOrErr)
return createFileError(Filename, BufOrErr.getError());

BufOrErr.get()->getBuffer().split(Lines, '\n');
for (size_t LineNo = 0, NumLines = Lines.size(); LineNo < NumLines;
++LineNo) {
StringRef TrimmedLine = Lines[LineNo].split('#').first.trim();
if (TrimmedLine.empty())
continue;

std::pair<StringRef, StringRef> Pair = Saver.save(TrimmedLine).split(' ');
StringRef NewName = Pair.second.trim();
if (NewName.empty())
return createStringError(errc::invalid_argument,
"%s:%zu: missing new DWO path",
Filename.str().c_str(), LineNo + 1);
DWOPathMap.insert({Pair.first, NewName});
}
return Error::success();
}

int llvm_dwp_main(int argc, char **argv, const llvm::ToolContext &) {
DwpOptTable Tbl;
llvm::BumpPtrAllocator A;
Expand Down Expand Up @@ -173,8 +208,16 @@ int llvm_dwp_main(int argc, char **argv, const llvm::ToolContext &) {
llvm::InitializeAllTargets();
llvm::InitializeAllAsmPrinters();

llvm::StringMap<StringRef> DWOPathMap;
for (auto *Arg : Args.filtered(OPT_execDwoPathRemappingFile)) {
if (Error E = addPathsToRemapFromFile(DWOPathMap, A, Arg->getValue())) {
logAllUnhandledErrors(std::move(E), WithColor::error());
return 1;
}
}

for (const auto &ExecFilename : ExecFilenames) {
auto DWOs = getDWOFilenames(ExecFilename);
auto DWOs = getDWOFilenames(ExecFilename, DWOPathMap);
if (!DWOs) {
logAllUnhandledErrors(
handleErrors(DWOs.takeError(),
Expand Down