[lld] 3a108ab - [LLD][COFF] Skip computation of the undefined symbols references that are not shown
Sylvain Audi via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 20 10:46:43 PDT 2020
Author: Sylvain Audi
Date: 2020-07-20T13:45:16-04:00
New Revision: 3a108ab256dba7b5a7304f0e83818673d334405f
URL: https://github.com/llvm/llvm-project/commit/3a108ab256dba7b5a7304f0e83818673d334405f
DIFF: https://github.com/llvm/llvm-project/commit/3a108ab256dba7b5a7304f0e83818673d334405f.diff
LOG: [LLD][COFF] Skip computation of the undefined symbols references that are not shown
The "undefined symbol" error message from lld-link displays up to 3 references to that symbol, and the number of extra references not shown.
This patch removes the computation of the strings for those extra references.
It fixes a freeze of lld-link we accidentally encountered when activating asan on a large project, without linking with the asan library.
In that case, __asan_report_load8 was referenced more than 2 million times, causing the computation of that many display strings, of which only 3 were used.
Differential Revision: https://reviews.llvm.org/D83510
Added:
lld/test/COFF/Inputs/undefined-symbol-multi-lto.ll
Modified:
lld/COFF/SymbolTable.cpp
lld/test/COFF/undefined-symbol-multi.s
Removed:
################################################################################
diff --git a/lld/COFF/SymbolTable.cpp b/lld/COFF/SymbolTable.cpp
index d4d2a159a639..173e32f628ef 100644
--- a/lld/COFF/SymbolTable.cpp
+++ b/lld/COFF/SymbolTable.cpp
@@ -136,12 +136,16 @@ getFileLine(const SectionChunk *c, uint32_t addr) {
// of all references to that symbol from that file. If no debug information is
// available, returns just the name of the file, else one string per actual
// reference as described in the debug info.
-std::vector<std::string> getSymbolLocations(ObjFile *file, uint32_t symIndex) {
+// Returns up to maxStrings string descriptions, along with the total number of
+// locations found.
+static std::pair<std::vector<std::string>, size_t>
+getSymbolLocations(ObjFile *file, uint32_t symIndex, size_t maxStrings) {
struct Location {
Symbol *sym;
std::pair<StringRef, uint32_t> fileLine;
};
std::vector<Location> locations;
+ size_t numLocations = 0;
for (Chunk *c : file->getChunks()) {
auto *sc = dyn_cast<SectionChunk>(c);
@@ -150,6 +154,10 @@ std::vector<std::string> getSymbolLocations(ObjFile *file, uint32_t symIndex) {
for (const coff_relocation &r : sc->getRelocs()) {
if (r.SymbolTableIndex != symIndex)
continue;
+ numLocations++;
+ if (locations.size() >= maxStrings)
+ continue;
+
Optional<std::pair<StringRef, uint32_t>> fileLine =
getFileLine(sc, r.VirtualAddress);
Symbol *sym = getSymbol(sc, r.VirtualAddress);
@@ -160,8 +168,12 @@ std::vector<std::string> getSymbolLocations(ObjFile *file, uint32_t symIndex) {
}
}
- if (locations.empty())
- return std::vector<std::string>({"\n>>> referenced by " + toString(file)});
+ if (maxStrings == 0)
+ return std::make_pair(std::vector<std::string>(), numLocations);
+
+ if (numLocations == 0)
+ return std::make_pair(
+ std::vector<std::string>{"\n>>> referenced by " + toString(file)}, 1);
std::vector<std::string> symbolLocations(locations.size());
size_t i = 0;
@@ -175,17 +187,26 @@ std::vector<std::string> getSymbolLocations(ObjFile *file, uint32_t symIndex) {
if (loc.sym)
os << ":(" << toString(*loc.sym) << ')';
}
- return symbolLocations;
+ return std::make_pair(symbolLocations, numLocations);
+}
+
+std::vector<std::string> getSymbolLocations(ObjFile *file, uint32_t symIndex) {
+ return getSymbolLocations(file, symIndex, SIZE_MAX).first;
}
-std::vector<std::string> getSymbolLocations(InputFile *file,
- uint32_t symIndex) {
+static std::pair<std::vector<std::string>, size_t>
+getSymbolLocations(InputFile *file, uint32_t symIndex, size_t maxStrings) {
if (auto *o = dyn_cast<ObjFile>(file))
- return getSymbolLocations(o, symIndex);
- if (auto *b = dyn_cast<BitcodeFile>(file))
- return getSymbolLocations(b);
+ return getSymbolLocations(o, symIndex, maxStrings);
+ if (auto *b = dyn_cast<BitcodeFile>(file)) {
+ std::vector<std::string> symbolLocations = getSymbolLocations(b);
+ size_t numLocations = symbolLocations.size();
+ if (symbolLocations.size() > maxStrings)
+ symbolLocations.resize(maxStrings);
+ return std::make_pair(symbolLocations, numLocations);
+ }
llvm_unreachable("unsupported file type passed to getSymbolLocations");
- return {};
+ return std::make_pair(std::vector<std::string>(), (size_t)0);
}
// For an undefined symbol, stores all files referencing it and the index of
@@ -205,20 +226,21 @@ static void reportUndefinedSymbol(const UndefinedDiag &undefDiag) {
os << "undefined symbol: " << toString(*undefDiag.sym);
const size_t maxUndefReferences = 3;
- size_t i = 0, numRefs = 0;
+ size_t numDisplayedRefs = 0, numRefs = 0;
for (const UndefinedDiag::File &ref : undefDiag.files) {
- std::vector<std::string> symbolLocations =
- getSymbolLocations(ref.file, ref.symIndex);
- numRefs += symbolLocations.size();
+ std::vector<std::string> symbolLocations;
+ size_t totalLocations = 0;
+ std::tie(symbolLocations, totalLocations) = getSymbolLocations(
+ ref.file, ref.symIndex, maxUndefReferences - numDisplayedRefs);
+
+ numRefs += totalLocations;
+ numDisplayedRefs += symbolLocations.size();
for (const std::string &s : symbolLocations) {
- if (i >= maxUndefReferences)
- break;
os << s;
- i++;
}
}
- if (i < numRefs)
- os << "\n>>> referenced " << numRefs - i << " more times";
+ if (numDisplayedRefs < numRefs)
+ os << "\n>>> referenced " << numRefs - numDisplayedRefs << " more times";
errorOrWarn(os.str());
}
diff --git a/lld/test/COFF/Inputs/undefined-symbol-multi-lto.ll b/lld/test/COFF/Inputs/undefined-symbol-multi-lto.ll
new file mode 100644
index 000000000000..5f6730272e61
--- /dev/null
+++ b/lld/test/COFF/Inputs/undefined-symbol-multi-lto.ll
@@ -0,0 +1,23 @@
+target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-windows-msvc"
+
+define dso_local i32 @"?baz@@YAHXZ"() #0 {
+ %1 = call i32 @"?foo@@YAHXZ"()
+ %2 = call i32 @"?foo@@YAHXZ"()
+ %3 = call i32 @"?bar@@YAHXZ"()
+ %4 = call i32 @"?bar@@YAHXZ"()
+ ret i32 0
+}
+
+declare dso_local i32 @"?foo@@YAHXZ"() #1
+
+declare dso_local i32 @"?bar@@YAHXZ"() #1
+
+attributes #0 = { noinline optnone uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.module.flags = !{!0}
+!llvm.ident = !{!1}
+
+!0 = !{i32 1, !"wchar_size", i32 2}
+!1 = !{!"clang version 11.0.0 (https://github.com/llvm/llvm-project.git bed3e1a99b41f5a9525bc0edf12ecbcf63aab0cf)"}
diff --git a/lld/test/COFF/undefined-symbol-multi.s b/lld/test/COFF/undefined-symbol-multi.s
index 2d3d8285338c..086d12828b2d 100644
--- a/lld/test/COFF/undefined-symbol-multi.s
+++ b/lld/test/COFF/undefined-symbol-multi.s
@@ -16,17 +16,20 @@
# RUN: echo ' call "?foo@@YAHXZ"' >> %t.moreref.s
# RUN: echo ' call "?foo@@YAHXZ"' >> %t.moreref.s
# RUN: llvm-mc -triple=x86_64-windows-msvc -filetype=obj -o %t2.obj %t.moreref.s
-# RUN: not lld-link /out:/dev/null %t.obj %t2.obj 2>&1 | FileCheck %s
+# RUN: llvm-as %S/Inputs/undefined-symbol-multi-lto.ll -o %t3.obj
+# RUN: not lld-link /out:/dev/null %t.obj %t2.obj %t3.obj 2>&1 | FileCheck %s
# CHECK: error: undefined symbol: int __cdecl foo(void)
# CHECK-NEXT: >>> referenced by {{.*}}tmp.obj:(main)
# CHECK-NEXT: >>> referenced by {{.*}}tmp.obj:(main)
# CHECK-NEXT: >>> referenced by {{.*}}tmp2.obj:(bar)
-# CHECK-NEXT: >>> referenced 9 more times
+# CHECK-NEXT: >>> referenced 10 more times
# CHECK-EMPTY:
# CHECK-NEXT: error: undefined symbol: int __cdecl bar(void)
# CHECK-NEXT: >>> referenced by {{.*}}.obj:(main)
# CHECK-NEXT: >>> referenced by {{.*}}.obj:(f1)
+# CHECK-NEXT: >>> referenced by {{.*}}undefined-symbol-multi-lto.ll
+# CHECK-NEXT: >>> {{.*}}tmp3.obj
.section .text,"xr",one_only,main
.globl main
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