[PATCH] D85527: [AIX] Generate unique module id based on PID and timestamp
Xiangling Liao via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 7 08:03:45 PDT 2020
Xiangling_L created this revision.
Xiangling_L added reviewers: jasonliu, hubert.reinterpretcast, daltenty, yusra.syeda.
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A unique module id, which is a part of sinit and sterm function names, is necessary to be unique. However, `getUniqueModuleId` will fail if there is no strong external symbol within a module.
We will turn to use PID and timestamp when this happens.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D85527
Files:
llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
llvm/test/CodeGen/PowerPC/aix-static-init-no-unique-module-id.ll
Index: llvm/test/CodeGen/PowerPC/aix-static-init-no-unique-module-id.ll
===================================================================
--- llvm/test/CodeGen/PowerPC/aix-static-init-no-unique-module-id.ll
+++ llvm/test/CodeGen/PowerPC/aix-static-init-no-unique-module-id.ll
@@ -1,7 +1,22 @@
-; RUN: not llc -mtriple powerpc-ibm-aix-xcoff < %s 2>&1 | FileCheck %s
-; RUN: not llc -mtriple powerpc64-ibm-aix-xcoff < %s 2>&1 | FileCheck %s
+; RUN: llc -mtriple powerpc-ibm-aix-xcoff < %s 2>&1 | FileCheck %s
+; RUN: llc -mtriple powerpc64-ibm-aix-xcoff < %s 2>&1 | FileCheck %s
@llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @foo, i8* null }]
- at llvm.global_dtors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 65535, void ()* @bar, i8* null }]
-; CHECK: LLVM ERROR: cannot produce a unique identifier for this module based on strong external symbols
+define internal void @foo() {
+ ret void
+}
+
+; Use PID and timestamp to generate a unique module id when strong external
+; symbols are not available in current module. The module id generated in this
+; way is not reproducible. A function name sample would be:
+; __sinit80000000_clang_1006931596810495_0.
+
+; CHECK: .lglobl foo[DS]
+; CHECK: .lglobl .foo
+; CHECK: .csect foo[DS]
+; CHECK: __sinit80000000_clang_[[MODULEID:[0-9]+]]_0:
+; CHECK: .foo:
+; CHECK: .__sinit80000000_clang_[[MODULEID]]_0:
+; CHECK: .globl __sinit80000000_clang_[[MODULEID]]_0
+; CHECK: .globl .__sinit80000000_clang_[[MODULEID]]_0
Index: llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -64,6 +64,7 @@
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Process.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
@@ -1835,6 +1836,13 @@
}
}
+static std::time_t getTime() {
+ std::time_t Now = time(nullptr);
+ if (Now < 0 || !isUInt<64>(Now))
+ return UINT64_MAX;
+ return Now;
+}
+
bool PPCAIXAsmPrinter::doInitialization(Module &M) {
const bool Result = PPCAsmPrinter::doInitialization(M);
@@ -1864,13 +1872,13 @@
// names.
if (GlobalUniqueModuleId.empty()) {
GlobalUniqueModuleId = getUniqueModuleId(&M);
- // FIXME: We need to figure out what to hash on or encode into the
- // unique ID we need.
- if (GlobalUniqueModuleId.compare("") == 0)
- llvm::report_fatal_error(
- "cannot produce a unique identifier for this module based on"
- " strong external symbols");
- GlobalUniqueModuleId = GlobalUniqueModuleId.substr(1);
+ if (GlobalUniqueModuleId.compare("") != 0)
+ GlobalUniqueModuleId = GlobalUniqueModuleId.substr(1);
+ else
+ // Use PID and current time as unique module id when we cannot
+ // generate one based on a module's strong external symbols.
+ GlobalUniqueModuleId = llvm::utostr(sys::Process::getProcessId()) +
+ llvm::utostr(getTime());
}
emitSpecialLLVMGlobal(&G);
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