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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
This commit is contained in:
Petr Pavlu 2018-07-11 20:17:54 +00:00
parent b90dd4b25b
commit a934f9da41
2 changed files with 76 additions and 4 deletions
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4
clang/lib/CodeGen/CodeGenModule.cpp
View File

@ -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());

76
clang/test/CodeGen/clang-sections-attribute.c Normal file
View File

@ -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