Introduce model of global initializers in Subzero.
Modifies both LLVM to ICE converter, and Subzero's bitcode reader,
to build Subzero's global initializers. Modifies target lowering
routines for global initializers to use this new model.
Also modifies both to now handle relocations in global variable
initializers.
BUG=None
R=jvoung@chromium.org, stichnot@chromium.org
Review URL: https://codereview.chromium.org/624663002
diff --git a/src/IceTargetLoweringX8632.cpp b/src/IceTargetLoweringX8632.cpp
index 9cac11d..e837710 100644
--- a/src/IceTargetLoweringX8632.cpp
+++ b/src/IceTargetLoweringX8632.cpp
@@ -23,6 +23,7 @@
#include "IceCfgNode.h"
#include "IceClFlags.h"
#include "IceDefs.h"
+#include "IceGlobalInits.h"
#include "IceInstX8632.h"
#include "IceOperand.h"
#include "IceRegistersX8632.h"
@@ -4428,38 +4429,10 @@
TargetGlobalInitX8632::TargetGlobalInitX8632(GlobalContext *Ctx)
: TargetGlobalInitLowering(Ctx) {}
-namespace {
-char hexdigit(unsigned X) { return X < 10 ? '0' + X : 'A' + X - 10; }
-}
-
-void TargetGlobalInitX8632::lower(const IceString &Name, SizeT Align,
- bool IsInternal, bool IsConst,
- bool IsZeroInitializer, SizeT Size,
- const char *Data, bool DisableTranslation) {
+void TargetGlobalInitX8632::lower(const GlobalAddress &Global,
+ bool DisableTranslation) {
if (Ctx->isVerbose()) {
- // TODO: Consider moving the dump output into the driver to be
- // reused for all targets.
- Ostream &Str = Ctx->getStrDump();
- Str << "@" << Name << " = " << (IsInternal ? "internal" : "external");
- Str << (IsConst ? " constant" : " global");
- Str << " [" << Size << " x i8] ";
- if (IsZeroInitializer) {
- Str << "zeroinitializer";
- } else {
- Str << "c\"";
- // Code taken from PrintEscapedString() in AsmWriter.cpp. Keep
- // the strings in the same format as the .ll file for practical
- // diffing.
- for (uint64_t i = 0; i < Size; ++i) {
- unsigned char C = Data[i];
- if (isprint(C) && C != '\\' && C != '"')
- Str << C;
- else
- Str << '\\' << hexdigit(C >> 4) << hexdigit(C & 0x0F);
- }
- Str << "\"";
- }
- Str << ", align " << Align << "\n";
+ Global.dump(Ctx->getStrDump());
}
if (DisableTranslation)
@@ -4489,35 +4462,86 @@
// .local NAME
// .comm NAME, SIZE, ALIGN
- IceString MangledName = Ctx->mangleName(Name);
+ // TODO(kschimpf): Don't mangle name if external and uninitialized. This
+ // will allow us to cross test relocations for references to external
+ // global variables.
+
+ IceString MangledName = Ctx->mangleName(Global.getName());
// Start a new section.
- if (IsConst) {
+ if (Ctx->getFlags().DataSections) {
+ Str << "\t.section\t.rodata." << MangledName << ",\"a\",@progbits\n";
+ } else if (Global.getIsConstant()) {
Str << "\t.section\t.rodata,\"a\",@progbits\n";
} else {
Str << "\t.type\t" << MangledName << ",@object\n";
Str << "\t.data\n";
}
- Str << "\t" << (IsInternal ? ".local" : ".global") << "\t" << MangledName
- << "\n";
- if (IsZeroInitializer) {
- if (IsConst) {
- Str << "\t.align\t" << Align << "\n";
- Str << MangledName << ":\n";
- Str << "\t.zero\t" << Size << "\n";
- Str << "\t.size\t" << MangledName << ", " << Size << "\n";
- } else {
- // TODO(stichnot): Put the appropriate non-constant
- // zeroinitializers in a .bss section to reduce object size.
- Str << "\t.comm\t" << MangledName << ", " << Size << ", " << Align
- << "\n";
+
+ Str << "\t" << (Global.getIsInternal() ? ".local" : ".global") << "\t"
+ << MangledName << "\n";
+
+ const GlobalAddress::InitializerListType &Initializers =
+ Global.getInitializers();
+
+ // Note: Handle zero initializations specially when lowering, since
+ // we may be able to reduce object size.
+ GlobalAddress::ZeroInitializer *SimpleZeroInit = nullptr;
+ if (Initializers.size() == 1) {
+ GlobalAddress::Initializer *Init = Initializers[0];
+ if (const auto ZeroInit =
+ llvm::dyn_cast<GlobalAddress::ZeroInitializer>(Init)) {
+ SimpleZeroInit = ZeroInit;
}
+ }
+
+ if (SimpleZeroInit && !Global.getIsConstant()) {
+ // TODO(stichnot): Put the appropriate non-constant
+ // zeroinitializers in a .bss section to reduce object size.
+ Str << "\t.comm\t" << MangledName << ", " << Global.getNumBytes() << ", "
+ << Global.getAlignment() << "\n";
+ // }
} else {
- Str << "\t.align\t" << Align << "\n";
+ Str << "\t.align\t" << Global.getAlignment() << "\n";
Str << MangledName << ":\n";
- for (SizeT i = 0; i < Size; ++i) {
- Str << "\t.byte\t" << (((unsigned)Data[i]) & 0xff) << "\n";
+ for (GlobalAddress::Initializer *Init : Initializers) {
+ switch (Init->getKind()) {
+ case GlobalAddress::Initializer::DataInitializerKind: {
+ const auto Data =
+ llvm::cast<GlobalAddress::DataInitializer>(Init)->getContents();
+ for (SizeT i = 0; i < Init->getNumBytes(); ++i) {
+ Str << "\t.byte\t" << (((unsigned)Data[i]) & 0xff) << "\n";
+ }
+ break;
+ }
+ case GlobalAddress::Initializer::ZeroInitializerKind:
+ Str << "\t.zero\t" << Init->getNumBytes() << "\n";
+ break;
+ case GlobalAddress::Initializer::RelocInitializerKind: {
+ const auto Reloc = llvm::cast<GlobalAddress::RelocInitializer>(Init);
+ Str << "\t.long\t";
+ // TODO(kschimpf): Once the representation of a relocation has
+ // been modified to reference the corresponding global
+ // address, modify to not mangle the name if the global is
+ // external and uninitialized. This will allow us to better
+ // test cross test relocations.
+ Str << Ctx->mangleName(Reloc->getName());
+ if (GlobalAddress::RelocOffsetType Offset = Reloc->getOffset()) {
+ Str << " + " << Offset;
+ }
+ Str << "\n";
+ break;
+ }
+ default: {
+ std::string Buffer;
+ llvm::raw_string_ostream StrBuf(Buffer);
+ StrBuf << "Unable to lower initializer: ";
+ Init->dump(StrBuf);
+ llvm::report_fatal_error(StrBuf.str());
+ break;
+ }
+ }
}
- Str << "\t.size\t" << MangledName << ", " << Size << "\n";
+ Str << "\t.size\t" << MangledName << ", " << Global.getNumBytes() << "\n";
}
}
