Fix setting of empty implicit-section-name attribute

Code in `CodeGenModule::SetFunctionAttributes()` could set an empty
attribute `implicit-section-name` on a function that is affected by
`#pragma clang text="section"`. This is incorrect because the attribute
should contain a valid section name. If the function additionally also
used `__attribute__((section("section")))` then this could result in
emitting the function in a section with an empty name.

The patch fixes the issue by removing the problematic code that sets
empty `implicit-section-name` from
`CodeGenModule::SetFunctionAttributes()` because it is sufficient to set
this attribute only from a similar code in `setNonAliasAttributes()`
when the function is emitted.

Differential Revision: https://reviews.llvm.org/D48916

llvm-svn: 336842

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 13afd4b..b412d30 100644 (file)
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1485,10 +1485,6 @@ void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
   setLinkageForGV(F, FD);
   setGVProperties(F, FD);
 
-  if (FD->getAttr<PragmaClangTextSectionAttr>()) {
-    F->addFnAttr("implicit-section-name");
-  }
-
   if (const SectionAttr *SA = FD->getAttr<SectionAttr>())
     F->setSection(SA->getName());
 

diff --git a/clang/test/CodeGen/clang-sections-attribute.c b/clang/test/CodeGen/clang-sections-attribute.c
new file mode 100644 (file)
index 0000000..7223d7d
--- /dev/null
+++ b/clang/test/CodeGen/clang-sections-attribute.c
@@ -0,0 +1,76 @@
+// RUN: %clang_cc1 -emit-llvm -triple arm-none-eabi -o - %s | FileCheck %s
+
+// Test interaction between __attribute__((section())) and '#pragma clang
+// section' directives. The attribute should always have higher priority than
+// the pragma.
+
+// Text tests.
+#pragma clang section text=".ext_fun_pragma"
+void ext_fun(void) __attribute__((section(".ext_fun_attr")));
+void ext_fun(void) {}
+#pragma clang section text=""
+
+void ext_fun2(void) __attribute__((section(".ext_fun2_attr")));
+#pragma clang section text=".ext_fun2_pragma"
+void ext_fun2(void) {}
+#pragma clang section text=""
+
+#pragma clang section text=".int_fun_pragma"
+static void int_fun(void) __attribute__((section(".int_fun_attr"), used));
+static void int_fun(void) {}
+#pragma clang section text=""
+
+static void int_fun2(void) __attribute__((section(".int_fun2_attr"), used));
+#pragma clang section text=".int_fun2_pragma"
+static void int_fun2(void) {}
+#pragma clang section text=""
+
+// Rodata tests.
+#pragma clang section rodata=".ext_const_pragma"
+__attribute__((section(".ext_const_attr")))
+const int ext_const = 1;
+#pragma clang section rodata=""
+
+#pragma clang section rodata=".int_const_pragma"
+__attribute__((section(".int_const_attr"), used))
+static const int int_const = 1;
+#pragma clang section rodata=""
+
+// Data tests.
+#pragma clang section data=".ext_var_pragma"
+__attribute__((section(".ext_var_attr")))
+int ext_var = 1;
+#pragma clang section data=""
+
+#pragma clang section data=".int_var_pragma"
+__attribute__((section(".int_var_attr"), used))
+static int int_var = 1;
+#pragma clang section data=""
+
+// Bss tests.
+#pragma clang section bss=".ext_zvar_pragma"
+__attribute__((section(".ext_zvar_attr")))
+int ext_zvar;
+#pragma clang section bss=""
+
+#pragma clang section bss=".int_zvar_pragma"
+__attribute__((section(".int_zvar_attr"), used))
+static int int_zvar;
+#pragma clang section bss=""
+
+// CHECK: @ext_const = constant i32 1, section ".ext_const_attr", align 4{{$}}
+// CHECK: @int_const = internal constant i32 1, section ".int_const_attr", align 4{{$}}
+// CHECK: @ext_var = global i32 1, section ".ext_var_attr", align 4{{$}}
+// CHECK: @int_var = internal global i32 1, section ".int_var_attr", align 4{{$}}
+// CHECK: @ext_zvar = global i32 0, section ".ext_zvar_attr", align 4{{$}}
+// CHECK: @int_zvar = internal global i32 0, section ".int_zvar_attr", align 4{{$}}
+// CHECK: define void @ext_fun() #0 section ".ext_fun_attr"
+// CHECK: define void @ext_fun2() #0 section ".ext_fun2_attr"
+// CHECK: define internal void @int_fun() #0 section ".int_fun_attr"
+// CHECK: define internal void @int_fun2() #0 section ".int_fun2_attr"
+//
+// Function attributes should not include implicit-section-name.
+// CHECK-NOT: attributes #0 = {{.*}}implicit-section-name
+//
+// No other attribute group should be present in the file.
+// CHECK-NOT: attributes #1