[lld] [lld-macho] Category Merger: add support for addrsig references (PR #90903)
via llvm-commits
llvm-commits at lists.llvm.org
Fri May 3 15:15:56 PDT 2024
https://github.com/alx32 updated https://github.com/llvm/llvm-project/pull/90903
>From 031c3ec947b711fa12dc5df7ee862d03f24c8405 Mon Sep 17 00:00:00 2001
From: Alex Borcan <alexborcan at fb.com>
Date: Thu, 2 May 2024 13:10:12 -0700
Subject: [PATCH 1/4] [lld-macho] Category Merger: add support for addrsig
references
---
lld/MachO/ObjC.cpp | 70 ++++++++++++++++---
...jc-category-merging-extern-class-minimal.s | 3 +
2 files changed, 63 insertions(+), 10 deletions(-)
diff --git a/lld/MachO/ObjC.cpp b/lld/MachO/ObjC.cpp
index 4760fffebe3b30..15bd87d8260f84 100644
--- a/lld/MachO/ObjC.cpp
+++ b/lld/MachO/ObjC.cpp
@@ -21,6 +21,8 @@
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/Support/TimeProfiler.h"
+#include <unordered_set>
+
using namespace llvm;
using namespace llvm::MachO;
using namespace lld;
@@ -420,6 +422,7 @@ class ObjcCategoryMerger {
mergeCategoriesIntoSingleCategory(std::vector<InfoInputCategory> &categories);
void eraseISec(ConcatInputSection *isec);
+ void removeRefsToErasedIsecs(std::unordered_set<InputSection *> erasedIsecs);
void eraseMergedCategories();
void generateCatListForNonErasedCategories(
@@ -460,7 +463,9 @@ class ObjcCategoryMerger {
Defined *tryGetDefinedAtIsecOffset(const ConcatInputSection *isec,
uint32_t offset);
void tryEraseDefinedAtIsecOffset(const ConcatInputSection *isec,
- uint32_t offset);
+ uint32_t offset,
+ std::unordered_set<InputSection *> &erased);
+ void eraseSymbolAtIsecOffset(ConcatInputSection *isec, uint32_t offset);
// Allocate a null-terminated StringRef backed by generatedSectionData
StringRef newStringData(const char *str);
@@ -518,6 +523,8 @@ void ObjcCategoryMerger::collectSectionWriteInfoFromIsec(
Symbol *
ObjcCategoryMerger::tryGetSymbolAtIsecOffset(const ConcatInputSection *isec,
uint32_t offset) {
+ if (!isec)
+ return nullptr;
const Reloc *reloc = isec->getRelocAt(offset);
if (!reloc)
@@ -536,7 +543,8 @@ ObjcCategoryMerger::tryGetDefinedAtIsecOffset(const ConcatInputSection *isec,
// Given an ConcatInputSection or CStringInputSection and an offset, if there is
// a symbol(Defined) at that offset, then erase the symbol (mark it not live)
void ObjcCategoryMerger::tryEraseDefinedAtIsecOffset(
- const ConcatInputSection *isec, uint32_t offset) {
+ const ConcatInputSection *isec, uint32_t offset,
+ std::unordered_set<InputSection *> &erased) {
const Reloc *reloc = isec->getRelocAt(offset);
if (!reloc)
@@ -546,9 +554,11 @@ void ObjcCategoryMerger::tryEraseDefinedAtIsecOffset(
if (!sym)
return;
- if (auto *cisec = dyn_cast_or_null<ConcatInputSection>(sym->isec()))
+ if (auto *cisec = dyn_cast_or_null<ConcatInputSection>(sym->isec())) {
eraseISec(cisec);
- else if (auto *csisec = dyn_cast_or_null<CStringInputSection>(sym->isec())) {
+ erased.insert(cisec);
+ } else if (auto *csisec =
+ dyn_cast_or_null<CStringInputSection>(sym->isec())) {
uint32_t totalOffset = sym->value + reloc->addend;
StringPiece &piece = csisec->getStringPiece(totalOffset);
piece.live = false;
@@ -1168,26 +1178,66 @@ void ObjcCategoryMerger::eraseMergedCategories() {
// the references to the ones we merged.
generateCatListForNonErasedCategories(catListToErasedOffsets);
+ // We use erasedIsecs below to track erased sections so we can later remove
+ // references to it.
+ std::unordered_set<InputSection *> erasedIsecs;
+ erasedIsecs.reserve(categoryMap.size());
+
// Erase the old method lists & names of the categories that were merged
for (auto &mapEntry : categoryMap) {
for (InfoInputCategory &catInfo : mapEntry.second) {
if (!catInfo.wasMerged)
continue;
+ erasedIsecs.insert(catInfo.catBodyIsec);
+ erasedIsecs.insert(catInfo.catListIsec);
+
eraseISec(catInfo.catBodyIsec);
- tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec, catLayout.nameOffset);
+ tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec, catLayout.nameOffset,
+ erasedIsecs);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.instanceMethodsOffset);
+ catLayout.instanceMethodsOffset, erasedIsecs);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.classMethodsOffset);
+ catLayout.classMethodsOffset, erasedIsecs);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.protocolsOffset);
+ catLayout.protocolsOffset, erasedIsecs);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.classPropsOffset);
+ catLayout.classPropsOffset, erasedIsecs);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.instancePropsOffset);
+ catLayout.instancePropsOffset, erasedIsecs);
}
}
+
+ removeRefsToErasedIsecs(erasedIsecs);
+}
+
+// The compiler may generate references to categories inside the addrsig
+// section. This function will erase these references.
+void ObjcCategoryMerger::removeRefsToErasedIsecs(
+ std::unordered_set<InputSection *> erasedIsecs) {
+ for (InputSection *isec : inputSections) {
+ if (isec->getName() != section_names::addrSig)
+ continue;
+
+ auto removeRelocs = [&erasedIsecs](Reloc &r) {
+ ConcatInputSection *isec = nullptr;
+ isec = dyn_cast_or_null<ConcatInputSection>(
+ r.referent.dyn_cast<InputSection *>());
+ if (!isec) {
+ Defined *sym =
+ dyn_cast_or_null<Defined>(r.referent.dyn_cast<Symbol *>());
+ if (sym)
+ isec = dyn_cast<ConcatInputSection>(sym->isec());
+ }
+ if (!isec)
+ return false;
+ return erasedIsecs.count(isec) > 0;
+ };
+
+ isec->relocs.erase(
+ std::remove_if(isec->relocs.begin(), isec->relocs.end(), removeRelocs),
+ isec->relocs.end());
+ }
}
void ObjcCategoryMerger::doMerge() {
diff --git a/lld/test/MachO/objc-category-merging-extern-class-minimal.s b/lld/test/MachO/objc-category-merging-extern-class-minimal.s
index ea79f29a421c5c..796993799f2db0 100644
--- a/lld/test/MachO/objc-category-merging-extern-class-minimal.s
+++ b/lld/test/MachO/objc-category-merging-extern-class-minimal.s
@@ -153,3 +153,6 @@ L_OBJC_IMAGE_INFO:
.long 0
.long 96
.subsections_via_symbols
+
+.addrsig
+.addrsig_sym __OBJC_$_CATEGORY_MyBaseClass_$_Category01
>From f46b5ae22561c25383f0b4036bb12fd12d0bb429 Mon Sep 17 00:00:00 2001
From: Alex Borcan <alexborcan at fb.com>
Date: Thu, 2 May 2024 17:41:07 -0700
Subject: [PATCH 2/4] Address feedback nr.1
---
lld/MachO/ObjC.cpp | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/lld/MachO/ObjC.cpp b/lld/MachO/ObjC.cpp
index 15bd87d8260f84..20abc730525f63 100644
--- a/lld/MachO/ObjC.cpp
+++ b/lld/MachO/ObjC.cpp
@@ -422,7 +422,7 @@ class ObjcCategoryMerger {
mergeCategoriesIntoSingleCategory(std::vector<InfoInputCategory> &categories);
void eraseISec(ConcatInputSection *isec);
- void removeRefsToErasedIsecs(std::unordered_set<InputSection *> erasedIsecs);
+ void removeRefsToErasedIsecs(std::unordered_set<InputSection *> &erasedIsecs);
void eraseMergedCategories();
void generateCatListForNonErasedCategories(
@@ -1189,10 +1189,13 @@ void ObjcCategoryMerger::eraseMergedCategories() {
if (!catInfo.wasMerged)
continue;
+ eraseISec(catInfo.catBodyIsec);
+ // Mark the category body as having been erased
erasedIsecs.insert(catInfo.catBodyIsec);
+
+ // Also mark the catListIsec as having been erased, it has already been erased above
erasedIsecs.insert(catInfo.catListIsec);
- eraseISec(catInfo.catBodyIsec);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec, catLayout.nameOffset,
erasedIsecs);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
@@ -1214,14 +1217,13 @@ void ObjcCategoryMerger::eraseMergedCategories() {
// The compiler may generate references to categories inside the addrsig
// section. This function will erase these references.
void ObjcCategoryMerger::removeRefsToErasedIsecs(
- std::unordered_set<InputSection *> erasedIsecs) {
+ std::unordered_set<InputSection *> &erasedIsecs) {
for (InputSection *isec : inputSections) {
if (isec->getName() != section_names::addrSig)
continue;
auto removeRelocs = [&erasedIsecs](Reloc &r) {
- ConcatInputSection *isec = nullptr;
- isec = dyn_cast_or_null<ConcatInputSection>(
+ auto *isec = dyn_cast_or_null<ConcatInputSection>(
r.referent.dyn_cast<InputSection *>());
if (!isec) {
Defined *sym =
>From 650113fdc315b2ce5164666de3eedb557c049918 Mon Sep 17 00:00:00 2001
From: Alex Borcan <alexborcan at fb.com>
Date: Fri, 3 May 2024 11:46:07 -0700
Subject: [PATCH 3/4] Address feedback nr.2
---
lld/MachO/ObjC.cpp | 46 ++++++++++++++++++----------------------------
1 file changed, 18 insertions(+), 28 deletions(-)
diff --git a/lld/MachO/ObjC.cpp b/lld/MachO/ObjC.cpp
index 20abc730525f63..7dc39dbf0a9ca4 100644
--- a/lld/MachO/ObjC.cpp
+++ b/lld/MachO/ObjC.cpp
@@ -422,7 +422,7 @@ class ObjcCategoryMerger {
mergeCategoriesIntoSingleCategory(std::vector<InfoInputCategory> &categories);
void eraseISec(ConcatInputSection *isec);
- void removeRefsToErasedIsecs(std::unordered_set<InputSection *> &erasedIsecs);
+ void removeRefsToErasedIsecs();
void eraseMergedCategories();
void generateCatListForNonErasedCategories(
@@ -463,8 +463,7 @@ class ObjcCategoryMerger {
Defined *tryGetDefinedAtIsecOffset(const ConcatInputSection *isec,
uint32_t offset);
void tryEraseDefinedAtIsecOffset(const ConcatInputSection *isec,
- uint32_t offset,
- std::unordered_set<InputSection *> &erased);
+ uint32_t offset);
void eraseSymbolAtIsecOffset(ConcatInputSection *isec, uint32_t offset);
// Allocate a null-terminated StringRef backed by generatedSectionData
@@ -483,6 +482,8 @@ class ObjcCategoryMerger {
std::vector<ConcatInputSection *> &allInputSections;
// Map of base class Symbol to list of InfoInputCategory's for it
DenseMap<const Symbol *, std::vector<InfoInputCategory>> categoryMap;
+ // Set for tracking InputSection erased via eraseISec
+ std::unordered_set<InputSection *> erasedIsecs;
// Normally, the binary data comes from the input files, but since we're
// generating binary data ourselves, we use the below array to store it in.
@@ -543,8 +544,7 @@ ObjcCategoryMerger::tryGetDefinedAtIsecOffset(const ConcatInputSection *isec,
// Given an ConcatInputSection or CStringInputSection and an offset, if there is
// a symbol(Defined) at that offset, then erase the symbol (mark it not live)
void ObjcCategoryMerger::tryEraseDefinedAtIsecOffset(
- const ConcatInputSection *isec, uint32_t offset,
- std::unordered_set<InputSection *> &erased) {
+ const ConcatInputSection *isec, uint32_t offset) {
const Reloc *reloc = isec->getRelocAt(offset);
if (!reloc)
@@ -556,7 +556,6 @@ void ObjcCategoryMerger::tryEraseDefinedAtIsecOffset(
if (auto *cisec = dyn_cast_or_null<ConcatInputSection>(sym->isec())) {
eraseISec(cisec);
- erased.insert(cisec);
} else if (auto *csisec =
dyn_cast_or_null<CStringInputSection>(sym->isec())) {
uint32_t totalOffset = sym->value + reloc->addend;
@@ -1151,6 +1150,8 @@ void ObjcCategoryMerger::generateCatListForNonErasedCategories(
}
void ObjcCategoryMerger::eraseISec(ConcatInputSection *isec) {
+ erasedIsecs.insert(isec);
+
isec->live = false;
for (auto &sym : isec->symbols)
sym->used = false;
@@ -1178,11 +1179,6 @@ void ObjcCategoryMerger::eraseMergedCategories() {
// the references to the ones we merged.
generateCatListForNonErasedCategories(catListToErasedOffsets);
- // We use erasedIsecs below to track erased sections so we can later remove
- // references to it.
- std::unordered_set<InputSection *> erasedIsecs;
- erasedIsecs.reserve(categoryMap.size());
-
// Erase the old method lists & names of the categories that were merged
for (auto &mapEntry : categoryMap) {
for (InfoInputCategory &catInfo : mapEntry.second) {
@@ -1190,39 +1186,33 @@ void ObjcCategoryMerger::eraseMergedCategories() {
continue;
eraseISec(catInfo.catBodyIsec);
- // Mark the category body as having been erased
- erasedIsecs.insert(catInfo.catBodyIsec);
-
- // Also mark the catListIsec as having been erased, it has already been erased above
- erasedIsecs.insert(catInfo.catListIsec);
- tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec, catLayout.nameOffset,
- erasedIsecs);
+ tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec, catLayout.nameOffset);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.instanceMethodsOffset, erasedIsecs);
+ catLayout.instanceMethodsOffset);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.classMethodsOffset, erasedIsecs);
+ catLayout.classMethodsOffset);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.protocolsOffset, erasedIsecs);
+ catLayout.protocolsOffset);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.classPropsOffset, erasedIsecs);
+ catLayout.classPropsOffset);
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
- catLayout.instancePropsOffset, erasedIsecs);
+ catLayout.instancePropsOffset);
}
}
- removeRefsToErasedIsecs(erasedIsecs);
+ removeRefsToErasedIsecs();
}
// The compiler may generate references to categories inside the addrsig
// section. This function will erase these references.
-void ObjcCategoryMerger::removeRefsToErasedIsecs(
- std::unordered_set<InputSection *> &erasedIsecs) {
+void ObjcCategoryMerger::removeRefsToErasedIsecs() {
for (InputSection *isec : inputSections) {
if (isec->getName() != section_names::addrSig)
continue;
- auto removeRelocs = [&erasedIsecs](Reloc &r) {
+ auto &_erasedIsecs = erasedIsecs;
+ auto removeRelocs = [&_erasedIsecs](Reloc &r) {
auto *isec = dyn_cast_or_null<ConcatInputSection>(
r.referent.dyn_cast<InputSection *>());
if (!isec) {
@@ -1233,7 +1223,7 @@ void ObjcCategoryMerger::removeRefsToErasedIsecs(
}
if (!isec)
return false;
- return erasedIsecs.count(isec) > 0;
+ return _erasedIsecs.count(isec) > 0;
};
isec->relocs.erase(
>From cee422b1db4a569ac3e89bf203d6088e42d9b7ac Mon Sep 17 00:00:00 2001
From: Alex Borcan <alexborcan at fb.com>
Date: Fri, 3 May 2024 15:15:32 -0700
Subject: [PATCH 4/4] Address feedback nr.3
---
lld/MachO/ObjC.cpp | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/lld/MachO/ObjC.cpp b/lld/MachO/ObjC.cpp
index 7dc39dbf0a9ca4..18d5344436b0d7 100644
--- a/lld/MachO/ObjC.cpp
+++ b/lld/MachO/ObjC.cpp
@@ -1211,8 +1211,7 @@ void ObjcCategoryMerger::removeRefsToErasedIsecs() {
if (isec->getName() != section_names::addrSig)
continue;
- auto &_erasedIsecs = erasedIsecs;
- auto removeRelocs = [&_erasedIsecs](Reloc &r) {
+ auto removeRelocs = [this](Reloc &r) {
auto *isec = dyn_cast_or_null<ConcatInputSection>(
r.referent.dyn_cast<InputSection *>());
if (!isec) {
@@ -1223,7 +1222,7 @@ void ObjcCategoryMerger::removeRefsToErasedIsecs() {
}
if (!isec)
return false;
- return _erasedIsecs.count(isec) > 0;
+ return erasedIsecs.count(isec) > 0;
};
isec->relocs.erase(
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