[llvm] 153df13 - [SanitizerCoverage] Fix types of __stop* and __start* symbols

[Ilya Leoshkevich via llvm-commits]

Author: Ilya Leoshkevich
Date: 2020-08-04T21:53:27+02:00
New Revision: 153df1373e5d3e0f16464233a3c17feb8a9eb3e9

URL: https://github.com/llvm/llvm-project/commit/153df1373e5d3e0f16464233a3c17feb8a9eb3e9
DIFF: https://github.com/llvm/llvm-project/commit/153df1373e5d3e0f16464233a3c17feb8a9eb3e9.diff

LOG: [SanitizerCoverage] Fix types of __stop* and __start* symbols

If a section is supposed to hold elements of type T, then the
corresponding CreateSecStartEnd()'s Ty parameter represents T*.
Forwarding it to GlobalVariable constructor causes the resulting
GlobalVariable's type to be T*, and its SSA value type to be T**, which
is one indirection too many. This issue is mostly masked by pointer
casts, however, the global variable still gets an incorrect alignment,
which causes SystemZ to choose wrong instructions to access the
section.

Added: 
    

Modified: 
    llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
    llvm/test/Instrumentation/SanitizerCoverage/inline-8bit-counters.ll
    llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
    llvm/test/Instrumentation/SanitizerCoverage/tracing.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index b6a9df57e431..0b27982acc02 100644
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -338,25 +338,24 @@ PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M,
 std::pair<Value *, Value *>
 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section,
                                            Type *Ty) {
-  GlobalVariable *SecStart =
-      new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, nullptr,
-                         getSectionStart(Section));
+  GlobalVariable *SecStart = new GlobalVariable(
+      M, Ty->getPointerElementType(), false, GlobalVariable::ExternalLinkage,
+      nullptr, getSectionStart(Section));
   SecStart->setVisibility(GlobalValue::HiddenVisibility);
-  GlobalVariable *SecEnd =
-      new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage,
-                         nullptr, getSectionEnd(Section));
+  GlobalVariable *SecEnd = new GlobalVariable(
+      M, Ty->getPointerElementType(), false, GlobalVariable::ExternalLinkage,
+      nullptr, getSectionEnd(Section));
   SecEnd->setVisibility(GlobalValue::HiddenVisibility);
   IRBuilder<> IRB(M.getContext());
-  Value *SecEndPtr = IRB.CreatePointerCast(SecEnd, Ty);
   if (!TargetTriple.isOSBinFormatCOFF())
-    return std::make_pair(IRB.CreatePointerCast(SecStart, Ty), SecEndPtr);
+    return std::make_pair(SecStart, SecEnd);
 
   // Account for the fact that on windows-msvc __start_* symbols actually
   // point to a uint64_t before the start of the array.
   auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy);
   auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr,
                            ConstantInt::get(IntptrTy, sizeof(uint64_t)));
-  return std::make_pair(IRB.CreatePointerCast(GEP, Ty), SecEndPtr);
+  return std::make_pair(IRB.CreatePointerCast(GEP, Ty), SecEnd);
 }
 
 Function *ModuleSanitizerCoverage::CreateInitCallsForSections(

diff  --git a/llvm/test/Instrumentation/SanitizerCoverage/inline-8bit-counters.ll b/llvm/test/Instrumentation/SanitizerCoverage/inline-8bit-counters.ll
index 775ce4fd772d..4f905428769a 100644
--- a/llvm/test/Instrumentation/SanitizerCoverage/inline-8bit-counters.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/inline-8bit-counters.ll
@@ -12,4 +12,4 @@ entry:
 ; CHECK:  store i8 %1, i8* getelementptr inbounds ([1 x i8], [1 x i8]* @__sancov_gen_, i64 0, i64 0), align 1, !nosanitize
   ret void
 }
-; CHECK: call void @__sanitizer_cov_8bit_counters_init(i8* bitcast (i8** @__start___sancov_cntrs to i8*), i8* bitcast (i8** @__stop___sancov_cntrs to i8*))
+; CHECK: call void @__sanitizer_cov_8bit_counters_init(i8* @__start___sancov_cntrs, i8* @__stop___sancov_cntrs)

diff  --git a/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll b/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
index 8b05aac813c6..c6845363a406 100644
--- a/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
@@ -20,4 +20,4 @@ define void @foo() {
 entry:
   ret void
 }
-; CHECK: call void @__sanitizer_cov_bool_flag_init(i1* bitcast (i1** @__start___sancov_bools to i1*), i1* bitcast (i1** @__stop___sancov_bools to i1*))
+; CHECK: call void @__sanitizer_cov_bool_flag_init(i1* @__start___sancov_bools, i1* @__stop___sancov_bools)

diff  --git a/llvm/test/Instrumentation/SanitizerCoverage/tracing.ll b/llvm/test/Instrumentation/SanitizerCoverage/tracing.ll
index 75a30d6b2b2b..163271cdefa7 100644
--- a/llvm/test/Instrumentation/SanitizerCoverage/tracing.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/tracing.ll
@@ -74,7 +74,7 @@ lj:
 ; CHECK_PC_GUARD: call void @longjmp
 ; CHECK_PC_GUARD: unreachable
 
-; CHECK_PC_GUARD: call void @__sanitizer_cov_trace_pc_guard_init(i32* bitcast (i32** @__start___sancov_guards to i32*), i32* bitcast (i32** @__stop___sancov_guards to i32*))
+; CHECK_PC_GUARD: call void @__sanitizer_cov_trace_pc_guard_init(i32* @__start___sancov_guards, i32* @__stop___sancov_guards)
 
 ; CHECK_PC_GUARD_DARWIN-LABEL: define void @foo
 ; CHECK_PC_GUARD_DARWIN: call void @__sanitizer_cov_trace_pc_guard
@@ -82,4 +82,4 @@ lj:
 ; CHECK_PC_GUARD_DARWIN: call void @__sanitizer_cov_trace_pc_guard
 ; CHECK_PC_GUARD_DARWIN-NOT: call void @__sanitizer_cov_trace_pc
 ; CHECK_PC_GUARD_DARWIN: ret void
-; CHECK_PC_GUARD_DARWIN: call void @__sanitizer_cov_trace_pc_guard_init(i32* bitcast (i32** @"\01section$start$__DATA$__sancov_guards" to i32*), i32* bitcast (i32** @"\01section$end$__DATA$__sancov_guards" to i32*))
+; CHECK_PC_GUARD_DARWIN: call void @__sanitizer_cov_trace_pc_guard_init(i32* @"\01section$start$__DATA$__sancov_guards", i32* @"\01section$end$__DATA$__sancov_guards")