Add Sema implementation of #pragma pack stack.
- Follows the MSVC (original) implementation, including support of
pack(show) (useful for testing).
- Implements support for named pack records which gcc seems to
ignore (or implements incorrectly).
- Not currently wired to anything, only functionality change is the
type checking of the pragma.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@57476 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 6ee4ae1..fee732f 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -25,6 +25,7 @@
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/HeaderSearch.h"
#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/StringExtras.h"
using namespace clang;
Sema::TypeTy *Sema::isTypeName(const IdentifierInfo &II, Scope *S) {
@@ -2559,3 +2560,97 @@
// FIXME: Add all the various semantics of linkage specifications
return LinkageSpecDecl::Create(Context, Loc, Language, dcl);
}
+
+void Sema::ActOnPragmaPack(PragmaPackKind Kind, IdentifierInfo *Name,
+ ExprTy *alignment, SourceLocation PragmaLoc,
+ SourceLocation LParenLoc, SourceLocation RParenLoc) {
+ Expr *Alignment = static_cast<Expr *>(alignment);
+
+ // If specified then alignment must be a "small" power of two.
+ unsigned AlignmentVal = 0;
+ if (Alignment) {
+ llvm::APSInt Val;
+ if (!Alignment->isIntegerConstantExpr(Val, Context) ||
+ !Val.isPowerOf2() ||
+ Val.getZExtValue() > 16) {
+ Diag(PragmaLoc, diag::warn_pragma_pack_invalid_alignment);
+ delete Alignment;
+ return; // Ignore
+ }
+
+ AlignmentVal = (unsigned) Val.getZExtValue();
+ }
+
+ switch (Kind) {
+ case Action::PPK_Default: // pack([n])
+ PackContext.setAlignment(AlignmentVal);
+ break;
+
+ case Action::PPK_Show: // pack(show)
+ // Show the current alignment, making sure to show the right value
+ // for the default.
+ AlignmentVal = PackContext.getAlignment();
+ // FIXME: This should come from the target.
+ if (AlignmentVal == 0)
+ AlignmentVal = 8;
+ Diag(PragmaLoc, diag::warn_pragma_pack_show, llvm::utostr(AlignmentVal));
+ break;
+
+ case Action::PPK_Push: // pack(push [, id] [, [n])
+ PackContext.push(Name);
+ // Set the new alignment if specified.
+ if (Alignment)
+ PackContext.setAlignment(AlignmentVal);
+ break;
+
+ case Action::PPK_Pop: // pack(pop [, id] [, n])
+ // MSDN, C/C++ Preprocessor Reference > Pragma Directives > pack:
+ // "#pragma pack(pop, identifier, n) is undefined"
+ if (Alignment && Name)
+ Diag(PragmaLoc, diag::warn_pragma_pack_pop_identifer_and_alignment);
+
+ // Do the pop.
+ if (!PackContext.pop(Name)) {
+ // If a name was specified then failure indicates the name
+ // wasn't found. Otherwise failure indicates the stack was
+ // empty.
+ Diag(PragmaLoc, diag::warn_pragma_pack_pop_failed,
+ Name ? "no record matching name" : "stack empty");
+
+ // FIXME: Warn about popping named records as MSVC does.
+ } else {
+ // Pop succeeded, set the new alignment if specified.
+ if (Alignment)
+ PackContext.setAlignment(AlignmentVal);
+ }
+ break;
+
+ default:
+ assert(0 && "Invalid #pragma pack kind.");
+ }
+}
+
+bool PragmaPackStack::pop(IdentifierInfo *Name) {
+ if (Stack.empty())
+ return false;
+
+ // If name is empty just pop top.
+ if (!Name) {
+ Alignment = Stack.back().first;
+ Stack.pop_back();
+ return true;
+ }
+
+ // Otherwise, find the named record.
+ for (unsigned i = Stack.size(); i != 0; ) {
+ --i;
+ if (strcmp(Stack[i].second.c_str(), Name->getName()) == 0) {
+ // Found it, pop up to and including this record.
+ Alignment = Stack[i].first;
+ Stack.erase(Stack.begin() + i, Stack.end());
+ return true;
+ }
+ }
+
+ return false;
+}