[llvm] 922f42d - [clang][AIX] Fix mcount name and call arguments

[Chris Bowler via llvm-commits]

Author: Michael Francis
Date: 2022-10-20T16:20:00-04:00
New Revision: 922f42d531b873db59fce81aefa4dcaae999d5ce

URL: https://github.com/llvm/llvm-project/commit/922f42d531b873db59fce81aefa4dcaae999d5ce
DIFF: https://github.com/llvm/llvm-project/commit/922f42d531b873db59fce81aefa4dcaae999d5ce.diff

LOG: [clang][AIX] Fix mcount name and call arguments

Currently, compiling a program with the `-pg` flag will result in an
undefined symbol error for `.mcount`. This revision fixes the call to
use `__mcount`, which requires a pointer argument to a pointer-sized
object (unique per inserted call) on AIX.

This is only a partial fix. This patch should fix the `-pg` flag's
behaviour on AIX to work with code you are compiling, but it will not
link against standard libraries with `mcount` instrumentation calls. The
next step is to add profiled libraries to the linker search paths in the
Clang driver for the AIX toolchain when linking with `-pg`.

Differential Review: https://reviews.llvm.org/D135384

Added: 
    clang/test/CodeGen/mcount-aix.c

Modified: 
    clang/lib/Basic/Targets/OSTargets.h
    llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Basic/Targets/OSTargets.h b/clang/lib/Basic/Targets/OSTargets.h
index 2d1a33ad9c0bc..88f7c4a3efc50 100644
--- a/clang/lib/Basic/Targets/OSTargets.h
+++ b/clang/lib/Basic/Targets/OSTargets.h
@@ -751,6 +751,7 @@ class AIXTargetInfo : public OSTargetInfo<Target> {
 public:
   AIXTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : OSTargetInfo<Target>(Triple, Opts) {
+    this->MCountName = "__mcount";
     this->TheCXXABI.set(TargetCXXABI::XL);
 
     if (this->PointerWidth == 64) {

diff  --git a/clang/test/CodeGen/mcount-aix.c b/clang/test/CodeGen/mcount-aix.c
new file mode 100644
index 0000000000000..6f5d9b3322e9b
--- /dev/null
+++ b/clang/test/CodeGen/mcount-aix.c
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -pg -triple powerpc-ibm-aix7.2.0.0 -S -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -pg -triple powerpc64-ibm-aix7.2.0.0 -S -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK64
+
+void foo() {
+}
+
+void bar() {
+    foo();
+}
+// CHECK: @[[GLOB0:[0-9]+]] = internal global i32 0
+// CHECK: @[[GLOB1:[0-9]+]] = internal global i32 0
+// CHECK64: @[[GLOB0:[0-9]+]] = internal global i64 0
+// CHECK64: @[[GLOB1:[0-9]+]] = internal global i64 0
+// CHECK-LABEL: @foo(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    call void @__mcount(ptr @[[GLOB0]])
+// CHECK64-LABEL: @foo(
+// CHECK64-NEXT:  entry:
+// CHECK64-NEXT:    call void @__mcount(ptr @[[GLOB0]])
+// CHECK-LABEL: @bar(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    call void @__mcount(ptr @[[GLOB1]])
+// CHECK64-LABEL: @bar(
+// CHECK64-NEXT:  entry:
+// CHECK64-NEXT:    call void @__mcount(ptr @[[GLOB1]])

diff  --git a/llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp b/llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp
index 60f910bceab89..53af1b1969c27 100644
--- a/llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp
+++ b/llvm/lib/Transforms/Utils/EntryExitInstrumenter.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
+#include "llvm/ADT/Triple.h"
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/Dominators.h"
@@ -34,9 +35,24 @@ static void insertCall(Function &CurFn, StringRef Func,
       Func == "__mcount" ||
       Func == "_mcount" ||
       Func == "__cyg_profile_func_enter_bare") {
-    FunctionCallee Fn = M.getOrInsertFunction(Func, Type::getVoidTy(C));
-    CallInst *Call = CallInst::Create(Fn, "", InsertionPt);
-    Call->setDebugLoc(DL);
+    Triple TargetTriple(M.getTargetTriple());
+    if (TargetTriple.isOSAIX() && Func == "__mcount") {
+      Type *SizeTy = M.getDataLayout().getIntPtrType(C);
+      Type *SizePtrTy = SizeTy->getPointerTo();
+      GlobalVariable *GV = new GlobalVariable(M, SizeTy, /*isConstant=*/false,
+                                              GlobalValue::InternalLinkage,
+                                              ConstantInt::get(SizeTy, 0));
+      CallInst *Call = CallInst::Create(
+          M.getOrInsertFunction(Func,
+                                FunctionType::get(Type::getVoidTy(C), {SizePtrTy},
+                                                  /*isVarArg=*/false)),
+          {GV}, "", InsertionPt);
+      Call->setDebugLoc(DL);
+    } else {
+      FunctionCallee Fn = M.getOrInsertFunction(Func, Type::getVoidTy(C));
+      CallInst *Call = CallInst::Create(Fn, "", InsertionPt);
+      Call->setDebugLoc(DL);
+    }
     return;
   }