Add support for #pragma clang section
This patch provides a means to specify section-names for global variables,
functions and static variables, using #pragma directives.
This feature is only defined to work sensibly for ELF targets.
One can specify section names as:
#pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
One can "unspecify" a section name with empty string e.g.
#pragma clang section bss="" data="" text="" rodata=""
Reviewers: Roger Ferrer, Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D33413
llvm-svn: 304704
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 1d232c7..3ba4a3a 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -248,6 +248,25 @@
const GlobalObject *GO, SectionKind Kind, const TargetMachine &TM) const {
StringRef SectionName = GO->getSection();
+ // Check if '#pragma clang section' name is applicable.
+ // Note that pragma directive overrides -ffunction-section, -fdata-section
+ // and so section name is exactly as user specified and not uniqued.
+ const GlobalVariable *GV = dyn_cast<GlobalVariable>(GO);
+ if (GV && GV->hasImplicitSection()) {
+ auto Attrs = GV->getAttributes();
+ if (Attrs.hasAttribute("bss-section") && Kind.isBSS()) {
+ SectionName = Attrs.getAttribute("bss-section").getValueAsString();
+ } else if (Attrs.hasAttribute("rodata-section") && Kind.isReadOnly()) {
+ SectionName = Attrs.getAttribute("rodata-section").getValueAsString();
+ } else if (Attrs.hasAttribute("data-section") && Kind.isData()) {
+ SectionName = Attrs.getAttribute("data-section").getValueAsString();
+ }
+ }
+ const Function *F = dyn_cast<Function>(GO);
+ if (F && F->hasFnAttribute("implicit-section-name")) {
+ SectionName = F->getFnAttribute("implicit-section-name").getValueAsString();
+ }
+
// Infer section flags from the section name if we can.
Kind = getELFKindForNamedSection(SectionName, Kind);