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-rw-r--r--llvm/include/llvm/IR/GlobalObject.h36
-rw-r--r--llvm/lib/IR/Globals.cpp26
-rw-r--r--llvm/lib/IR/LLVMContextImpl.h7
3 files changed, 59 insertions, 10 deletions
diff --git a/llvm/include/llvm/IR/GlobalObject.h b/llvm/include/llvm/IR/GlobalObject.h
index 11eb713a4e1..1057f564aab 100644
--- a/llvm/include/llvm/IR/GlobalObject.h
+++ b/llvm/include/llvm/IR/GlobalObject.h
@@ -37,11 +37,11 @@ protected:
setGlobalValueSubClassData(0);
}
- std::string Section; // Section to emit this into, empty means default
Comdat *ObjComdat;
enum {
LastAlignmentBit = 4,
HasMetadataHashEntryBit,
+ HasSectionHashEntryBit,
GlobalObjectBits,
};
@@ -66,8 +66,26 @@ public:
unsigned getGlobalObjectSubClassData() const;
void setGlobalObjectSubClassData(unsigned Val);
- bool hasSection() const { return !getSection().empty(); }
- StringRef getSection() const { return Section; }
+ /// Check if this global has a custom object file section.
+ ///
+ /// This is more efficient than calling getSection() and checking for an empty
+ /// string.
+ bool hasSection() const {
+ return getGlobalValueSubClassData() & (1 << HasSectionHashEntryBit);
+ }
+
+ /// Get the custom section of this global if it has one.
+ ///
+ /// If this global does not have a custom section, this will be empty and the
+ /// default object file section (.text, .data, etc) will be used.
+ StringRef getSection() const {
+ return hasSection() ? getSectionImpl() : StringRef();
+ }
+
+ /// Change the section for this global.
+ ///
+ /// Setting the section to the empty string tells LLVM to choose an
+ /// appropriate default object file section.
void setSection(StringRef S);
bool hasComdat() const { return getComdat() != nullptr; }
@@ -134,14 +152,20 @@ public:
void clearMetadata();
private:
+ void setGlobalObjectFlag(unsigned Bit, bool Val) {
+ unsigned Mask = 1 << Bit;
+ setGlobalValueSubClassData((~Mask & getGlobalValueSubClassData()) |
+ (Val ? Mask : 0u));
+ }
+
bool hasMetadataHashEntry() const {
return getGlobalValueSubClassData() & (1 << HasMetadataHashEntryBit);
}
void setHasMetadataHashEntry(bool HasEntry) {
- unsigned Mask = 1 << HasMetadataHashEntryBit;
- setGlobalValueSubClassData((~Mask & getGlobalValueSubClassData()) |
- (HasEntry ? Mask : 0u));
+ setGlobalObjectFlag(HasMetadataHashEntryBit, HasEntry);
}
+
+ StringRef getSectionImpl() const;
};
} // end namespace llvm
diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index 31f89514151..6f7356524d3 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -24,6 +24,7 @@
#include "llvm/IR/Operator.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
+#include "LLVMContextImpl.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
@@ -37,6 +38,10 @@ static_assert(sizeof(GlobalValue) ==
sizeof(Constant) + 2 * sizeof(void *) + 2 * sizeof(unsigned),
"unexpected GlobalValue size growth");
+// GlobalObject adds a comdat.
+static_assert(sizeof(GlobalObject) == sizeof(GlobalValue) + sizeof(void *),
+ "unexpected GlobalObject size growth");
+
bool GlobalValue::isMaterializable() const {
if (const Function *F = dyn_cast<Function>(this))
return F->isMaterializable();
@@ -160,11 +165,24 @@ Comdat *GlobalValue::getComdat() {
return cast<GlobalObject>(this)->getComdat();
}
-void GlobalObject::setSection(StringRef S) {
- Section = S;
+StringRef GlobalObject::getSectionImpl() const {
+ assert(hasSection());
+ return getContext().pImpl->GlobalObjectSections[this];
+}
- // The C api requires this to be null terminated.
- Section.c_str();
+void GlobalObject::setSection(StringRef S) {
+ // Do nothing if we're clearing the section and it is already empty.
+ if (!hasSection() && S.empty())
+ return;
+
+ // Get or create a stable section name string and put it in the table in the
+ // context.
+ S = getContext().pImpl->SectionStrings.insert(S).first->first();
+ getContext().pImpl->GlobalObjectSections[this] = S;
+
+ // Update the HasSectionHashEntryBit. Setting the section to the empty string
+ // means this global no longer has a section.
+ setGlobalObjectFlag(HasSectionHashEntryBit, !S.empty());
}
bool GlobalValue::isDeclaration() const {
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index e9e30ef0656..850c81cfabb 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -26,6 +26,7 @@
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSet.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DerivedTypes.h"
@@ -1194,6 +1195,12 @@ public:
/// Collection of per-GlobalObject metadata used in this context.
DenseMap<const GlobalObject *, MDGlobalAttachmentMap> GlobalObjectMetadata;
+ /// Collection of per-GlobalObject sections used in this context.
+ DenseMap<const GlobalObject *, StringRef> GlobalObjectSections;
+
+ /// Stable collection of section strings.
+ StringSet<> SectionStrings;
+
/// DiscriminatorTable - This table maps file:line locations to an
/// integer representing the next DWARF path discriminator to assign to
/// instructions in different blocks at the same location.
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